Physiological Function of Dietary Antioxidants, Mechanism of Lipid Peroxidation (antioxidant, lipid peroxidation, oxidative stress, flavonoids, carotenoids)
Book / Paper
Book:
1.
Y Bandaruk, Rie Mukai and Junji Terao : Role of flavonoids as possible monoamine oxidase-A regulators in the model of serotoninergic neuroblastoma SH-SY5Y cell., Ed by K. Yoshida, Yujinsha,
Baetta G., Consentino M.T., Sakurada S., M Piskula and Junji Terao : Herbal Medicines for Human Health, --- Bioavailability issues of non-nutrient plant and fruit constituents. ---, CRC press, Sep. 2012.
12.
Junji Terao, .E. Jeremy P Spencer and Alan Crozier : Flavonoids nad Related compounds-Bioavilability and function-., --- Bioavailability of Flavonols and flavones. ---, CRC press, Apr. 2012.
13.
Rie Mukai and Junji Terao : 「イソフラボンと抗酸化活性評価」, フジメディカル出版, Oct. 2011.
14.
Rintaro Yamanishi, Junji Terao and Hitoshi Takamura : Functional Food Science, 光生館, Tokyo, Oct. 2011.
Junji Terao : ビタミン総合事典 /日本ビタミン学会編集, 朝倉書店, Tokyo, Nov. 2010.
18.
新井 博文 and Junji Terao : 食品機能素材IV, CMC Publishing Co.,Ltd., Tokyo, Nov. 2010.
19.
Junji Terao : からだと光の事典/太陽紫外線防御研究委員会, 朝倉書店, Tokyo, Nov. 2010.
20.
Junji Terao, Kaeko Murota and Yoshichika Kawai : Recent Advances in Polyphenol Research, Volume2, --- Chapter8 Antiatheroscletic Effects of Dietary Flavonoids:Insight into their Molecular Action Mechanism at the Target Site ---, Wiley-Blackwell, Jul. 2010.
21.
Junji Terao : PLANE PHENOLICS AND HUMAN HEALTH, --- 8. Flavonols:Metabolism,Bioavailability,and Health Impact ---, John Wiley & Sons, Inc., Nov. 2009.
22.
Junji Terao : Dietary Flavonoids as Antioxodants, Karger, 2009.
23.
Junji Terao : 栄養学研究の最前線 (小川正，河田照雄・寺尾純二編集), KENPAKUSHA, Tokyo, Apr. 2008.
24.
Junji Terao : 機能性食品の科学「ユビキノン」, 朝倉書店, Tokyo, Aug. 2007.
25.
Junji Terao, Akihiko Nagao and Noriko Bando : 機能性食品の事典, 朝倉書店, Tokyo, Aug. 2007.
26.
Junji Terao and 榊原 啓之 : 抗ストレス食品の開発と展望, CMC Publishing Co.,Ltd., Tokyo, Oct. 2006.
27.
Junji Terao : 人参サポニン・羅府痲エキス, CMC Publishing Co.,Ltd., Tokyo, Oct. 2006.
Sayuri Miyamoto, Kaeko Murota and Junji Terao : High Oxidizability of Large Intestinal Mucosa in Iron Ion-Induced Lipid Peroxidation, Karger, 2001.
Academic Paper (Judged Full Paper):
1.
Yoshiaki Tanaka, Hitomi Okuyama, Miyu Nishikawa, Shin-ichi Ikushiro, Mayumi Ikeda, Yu Ishima, Yuichi Ukawa, Kenichi Oe, Junji Terao and Rie Mukai : 8-Prenylnaringenin tissue distribution and pharmacokinetics in mice and its binding to human serum albumin and cellular uptake in human embryonic kidney cells., Food Science & Nutrition, Vol.10, No.4, 1070-1080, 2022.
(Summary)
8-Prenylnaringenin (8-PN), a hop flavonoid, is a promising food substance with health benefits. Compared with nonprenylated naringenin, 8-PN exhibits stronger estrogenic activity and prevents muscle atrophy. Moreover, 8-PN prevents hot flushes and bone loss. Considering that prenylation reportedly improves the bioavailability of flavonoids, we compared the parameters related to the bioavailability [pharmacokinetics and tissue distribution in C57/BL6 mice, binding affinity to human serum albumin (HSA), and cellular uptake in HEK293 cells] of 8-PN and its mother (non-prenylated) compound naringenin. C57/BL6 mice were fed an 8-PN or naringenin mixed diet for 22 days. The amount of 8-PN (nmol/g tissue) in the kidneys (16.8 ± 9.20), liver (14.8 ± 2.58), muscles (3.33 ± 0.60), lungs (2.07 ± 0.68), pancreas (1.80 ± 0.38), heart (1.71 ± 0.27), spleen (1.36 ± 0.29), and brain (0.31 ± 0.09) was higher than that of naringenin. A pharmacokinetic study in mice demonstrated that the of 8-PN (50 mg/kg body weight) was lower than that of naringenin; however, the plasma concentration of 8-PN 8 h after ingestion was higher than that of naringenin. The binding affinity of 8-PN to HSA and cellular uptake in HEK293 cells were higher than those of naringenin. 8-PN bioavailability features assessed in mouse or human model experiments were obviously different from those of naringenin.
Akari Kondo-Kawai, Tohru Sakai, Junji Terao and Rie Mukai : Suppressive effects of quercetin on hydrogen peroxide-induced caveolin-1 phosphorylation in endothelial cells, Journal of Clinical Biochemistry and Nutrition, Vol.69, No.1, 1-9, 2021.
(Summary)
Caveolin-1 is a major protein of the caveolae structure in vascular endothelial cell membrane. Phosphorylation of caveolin-1 is one of the initial events leading to exacerbation of vascular permeability caused by oxidative stress. Although quercetin is known to be an anti-atherosclerosis factor that acts as a dietary antioxidant, little is known about its role in the regulation of caveolin-1 phosphorylation. In this study, we investigated the inhibitory effect of quercetin on hydrogen peroxide-induced caveolin-1 phosphorylation in human umbilical vein endothelial cells. Quercetin inhibited caveolin-1 phosphorylation in cells pretreated with quercetin for 24 h and then exposed to hydrogen peroxide. However, quercetin 3--β-glucuronide, a conjugated metabolite of quercetin, did not exert this inhibitory effect. Exposure to hydrogen peroxide increased vascular permeability and reduced mRNA expression of the intercellular adhesion protein, vascular endothelial cadherin (VE-cadherin). By contrast, pretreatment with quercetin suppressed the increase in vascular permeability and decreased VE-cadherin expression. These results indicate that deconjugated quercetin can play a role in the prevention of altered vascular permeability under oxidative stress by suppressing caveolin-1 phosphorylation. Thus, dietary quercetin may be beneficial for the maintenance of endothelial cell function.
Rie Mukai, Takashi Fukuda, Asami Ohnishi, Takeshi Nikawa, Mutsuki Furusawa and Junji Terao : Chocolate as a food matrix reduces the bioavailability of galloylated catechins from green tea in healthy women., Food & Function, Vol.12, No.1, 408-416, 2021.
(Summary)
In this study, we evaluated the food matrix effects of chocolate on the absorption of green tea catechins (GTCs), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg), and (-)-epigallocatechin gallate (EGCg), in five healthy 22-year-old women. In the single-intake experiment, the plasma concentrations of ECg (P < 0.05, at 1.5 h) and EGCg (P < 0.05, at 6 h) but not those of EC and EGC were reduced by the chocolate matrix. Regardless of the chocolate matrix, ECg and EGCg were mainly present as their aglycones in the plasma, whereas EGC and EC were found mostly as conjugated metabolites. After daily intake of GTCs mixed with chocolate for 14 days followed by overnight fasting, ECg but not EGCg was detected in the plasma. To compare the plasma profiles of ECg and EGCg, a mixture containing approximately equal amounts of ECg and EGCg was administered to nine rats for 14 days. Following treatment and overnight food deprivation, the plasma content of ECg was higher than that of EGCg. After a single injection of the same mixture in seven rats, ECg levels were higher than those of EGCg, and a greater amount of conjugated metabolites of ECg than those of EGCg was detected in the plasma 10 h after administration. In conclusion, the chocolate matrix affects the plasma profiles of GTCs, particularly ECg. ECg appears to persist in the plasma for a longer period, regardless of the chocolate matrix.
Erika Nuka, Kohta Ohnishi, Junji Terao and Yoshichika Kawai : ATP/P2X7 receptor signaling as a potential anti-inflammatory target of natural polyphenols., PLoS ONE, Vol.13, No.9, e0204229, 2018.
(Summary)
Innate immune cells, such as macrophages, respond to pathogen-associated molecular patterns, such as a lipopolysaccharide (LPS), to secrete various inflammatory mediators. Recent studies have suggested that damage-associated molecular patterns (DAMPs), released extracellularly from damaged or immune cells, also play a role in the activation of inflammatory responses. In this study, to prevent excess inflammation, we focused on DAMPs-mediated signaling that promotes LPS-stimulated inflammatory responses, especially adenosine 5'-triphosphate (ATP)-triggered signaling through the ionotropic purinergic receptor 7 (P2X7R), as a potential new anti-inflammatory target of natural polyphenols. We focused on the phenomenon that ATP accelerates the production of inflammatory mediators, such as nitric oxide, in LPS-stimulated J774.1 mouse macrophages. Using an siRNA-mediated knockdown and specific antagonist, it was found that the ATP-induced enhanced inflammatory responses were mediated through P2X7R. We then screened 42 polyphenols for inhibiting the ATP/P2X7R-induced calcium influx, and found that several polyphenols exhibited significant inhibitory effects. Especially, a flavonoid baicalein significantly inhibited ATP-induced inflammation, including interleukin-1β secretion, through inhibition of the ATP/P2X7R signaling. These findings suggest that ATP/P2X7R signaling plays an important role in excess inflammatory responses and could be a potential anti-inflammatory target of natural polyphenolic compounds.
Agustin Martin Morales, Rie Mukai, Kaeko Murota and Junji Terao : Inhibitory effect of catecholic colonic metabolites of rutin on fatty acid hydroperoxide and hemoglobin dependent lipid peroxidation in Caco-2 cells., Journal of Clinical Biochemistry and Nutrition, Vol.63, No.3, 175-180, 2018.
(Summary)
To determine the preventive effect of dietary rutin on oxidative damages occurring in the digestive tract, 13-hydroperoxyoctadecadienoic acid and hemoglobin were exposed to Caco-2 intestinal cells after the pretreatment with colonic rutin metabolites. Among four catechol-type metabolites, quercetin and 3,4-dihydroxytoluene exerted significant protection on 13-hydroperoxyoctadecadienoic and hemoglobin-dependent lipid peroxidation of this epithelial cell. Compared with quercetin, a much lower concentration allowed 3,4-dihydroxytoluene to maximize the protective effect, though it needed a longer pre-incubation period. Neither quercetin nor 3,4-dihydroxytoluene affected the expression of peroxiredoxin-6 protein, which comprises the cellular antioxidant defense system. It is concluded that 3,4-dihydroxytoluene is a plausible rutin colonic metabolite that can suppress oxidative damages of intestinal epithelial cells by directly inhibiting lipid peroxidation. This result may illuminate the preventive role of dietary rutin against colorectal cancer incidence in relation to the consumption of red and processed meat.
Rie Mukai, Hitomi Horikawa, Pei-Yi Lin, Nao Tsukumo, Takeshi Nikawa, Tomoyuki Kawamura, Hisao Nemoto and Junji Terao : 8-Prenylnaringenin promotes recovery from immobilization-induced disuse muscle atrophy through activation of the Akt phosphorylation pathway in mice., American Journal of Physiology. Regulatory, Integrative and Comparative Physiology, Vol.311, No.6, R1022-R1031, 2016.
(Summary)
8-Prenylnaringenin (8-PN) is a prenylflavonoid that originates from hop extracts and is thought to help prevent disuse muscle atrophy. We hypothesized that 8-PN affects muscle plasticity by promoting muscle recovery under disuse muscle atrophy. To test the promoting effect of 8-PN on muscle recovery, we administered an 8-PN mixed diet to mice that had been immobilized with a cast to one leg for 14 days. Intake of the 8-PN mixed diet accelerated recovery from muscle atrophy, and prevented reductions in Akt phosphorylation. Studies on cell cultures of mouse myotubes in vitro demonstrated that 8-PN activated the PI3K/Akt/P70S6K1 pathway at physiological concentrations. A cell-culture study using an inhibitor of estrogen receptors and an in vivo experiment with ovariectomized mice suggested that the estrogenic activity of 8-PN contributed to recovery from disuse muscle atrophy through activation of an Akt phosphorylation pathway. These data strongly suggest that 8-PN is a naturally occurring compound that could be used as a nutritional supplement to aid recovery from disuse muscle atrophy.
(Keyword)
Animals / Cell Line / Enzyme Activation / Flavanones / Hindlimb Suspension / Male / Mice / Mice, Inbred C57BL / Muscle Proteins / Muscle, Skeletal / Muscular Atrophy / Oncogene Protein v-akt / phosphorylation / Phytoestrogens / Protein Biosynthesis / Recovery of Function / signal transduction / Treatment Outcome
Chiemi Kamada, Rie Mukai, Akari Kondo, Shinya Sato and Junji Terao : Effect of quercetin and its metabolite on caveolin-1 expression induced by oxidized LDL and lysophosphatidylcholine in endothelial cells., Journal of Clinical Biochemistry and Nutrition, Vol.58, No.3, 193-201, 2016.
(Summary)
Oxidized low-density lipoprotein contributes to atherosclerotic plaque formation, and quercetin is expected to exert anti-atherosclerotic effects. We previously reported accumulation of conjugated quercetin metabolites in the aorta of rabbits fed high-cholesterol diets with quercetin glucosides, resulting in attenuation of lipid peroxidation and inhibition of lipid accumulation. Caveolin-1, a major structural protein of caveolae in vascular endothelial cells, plays a role in atherosclerosis development. Here we investigated effects of oxidized low-density lipoprotein, quercetin and its metabolite, quercetin 3-O--glucuronide, on caveolin-1 expression. Oxidized low-density lipoprotein significantly upregulated caveolin-1 mRNA expression. An oxidized low-density lipoprotein component, lysophosphatidylcholine, also induced expression of both caveolin-1 mRNA and protein. However, lysophosphatidylcholine did not affect the location of caveolin-1 proteins within caveolae structures. Co-treatment with quercetin or quercetin 3-O--glucuronide inhibited lysophosphatidylcholine-induced caveolin-1 expression. Quercetin and quercetin 3-O--glucuronide also suppressed expression of adhesion molecules induced by oxidized low-density lipoprotein and lysophosphatidylcholine. These results strongly suggest lysophosphatidylcholine derived from oxidized low-density lipoprotein contributes to atherosclerotic events by upregulating caveolin-1 expression, resulting in induction of adhesion molecules. Quercetin metabolites are likely to exert an anti-atherosclerotic effect by attenuating caveolin-1 expression in endothelial cells.
Rie Mukai, Naoko Matsui, Yutaka Fujikura, Norifumi Matsumoto, De-Xing Hou, Noriyuki Kanzaki, Hiroshi Shibata, Manabu Horikawa, Keiko Iwasa, Katsuya Hirasaka, Takeshi Nikawa and Junji Terao : Preventive effect of dietary quercetin on disuse muscle atrophy by targeting mitochondria in denervated mice., The Journal of Nutritional Biochemistry, Vol.31, 67-76, 2016.
(Summary)
Quercetin is a major dietary flavonoid in fruits and vegetables. We aimed to clarify the preventive effect of dietary quercetin on disuse muscle atrophy and the underlying mechanisms. We established a mouse denervation model by cutting the sciatic nerve in the right leg (SNX surgery) to lack of mobilization in hind-limb. Preintake of a quercetin-mixed diet for 14days before SNX surgery prevented loss of muscle mass and atrophy of muscle fibers in the gastrocnemius muscle (GM). Phosphorylation of Akt, a key phosphorylation pathway of suppression of protein degradation, was activated in the quercetin-mixed diet group with and without SNX surgery. Intake of a quercetin-mixed diet suppressed the generation of hydrogen peroxide originating from mitochondria and elevated mitochondrial peroxisome proliferator-activated receptor- coactivator 1 mRNA expression as well as NADH dehydrogenase 4 expression in the GM with SNX surgery. Quercetin and its conjugated metabolites reduced hydrogen peroxide production in the mitochondrial fraction obtained from atrophied muscle. In C2C12 myotubes, quercetin reached the mitochondrial fraction. These findings suggest that dietary quercetin can prevent disuse muscle atrophy by targeting mitochondria in skeletal muscle tissue through protecting mitochondria from decreased biogenesis and reducing mitochondrial hydrogen peroxide release, which can be related to decreased hydrogen peroxide production and/or improvements on antioxidant capacity of mitochondria.
Katsuya Hirasaka, Shinobu Saito, Saki Yamaguchi, Riho Miyazaki, Yao Wang, Marie Haruna, Shigeto Taniyama, Atsushi Higashitani, Junji Terao, Takeshi Nikawa and Katsuyasu Tachibana : Dietary Supplementation with Isoflavones Prevents Muscle Wasting in Tumor-Bearing Mice., Journal of Nutritional Science and Vitaminology, Vol.62, No.3, 178-184, 2016.
(Summary)
Proinflammatory cytokines contribute to the progression of muscle wasting caused by ubiquitin-proteasome-dependent proteolysis. We have previously demonstrated that isoflavones, such as genistein and daidzein, prevent TNF--induced muscle atrophy in C2C12 myotubes. In this study, we examined the effect of dietary flavonoids on the wasting of muscle. Mice were divided into the following four groups: vehicle-injected (control) mice fed the normal diet (CN); tumor-bearing mice fed the normal diet (TN); control mice fed the isoflavone diet (CI); and tumor-bearing mice fed the isoflavone diet (TI). There were no significant differences in the intake of food or body weight gain among these four groups. The wet weight and myofiber size of gastrocnemius muscle in TN significantly decreased, compared with those in CN. Interestingly, the wet weight and myofiber size of gastrocnemius muscle in TI were nearly the same as those in CN and CI, although isoflavone supplementation did not affect the increased tumor mass or concentrations of proinflammatory cytokines, such as TNF- and IL-6, in the blood. Moreover, increased expression of muscle-specific ubiquitin ligase genes encoding MAFbx/Atrogin-1 and MuRF1 in the skeletal muscle of TN was significantly inhibited by the supplementation of isoflavones. In parallel with the expression of muscle-specific ubiquitin ligases, dietary isoflavones significantly suppressed phosphorylation of ERK in tumor-bearing mice. These results suggest that dietary isoflavones improve muscle wasting in tumor-bearing mice via the ERK signaling pathway mediated-suppression of ubiquitin ligases in muscle cells.
Uncoupling protein 3 (UCP3) and pyruvate dehydrogenase kinase 4 (PDK4) in skeletal muscle are key regulators of the glucose and lipid metabolic processes that are involved in insulin resistance. Medium-chain fatty acids (MCFAs) have anti-obesogenic effects in rodents and humans, while long-chain fatty acids (LCFAs) cause increases in body weight and insulin resistance. To clarify the beneficial effects of MCFAs, we examined UCP3 and PDK4 expression in skeletal muscles of mice fed a MCFA- or LCFA-enriched high-fat diet (HFD). Five-week feeding of the LCFA-enriched HFD caused high body weight gain and induced glucose intolerance in mice, compared with those in mice fed the MCFA-enriched HFD. However, the amounts of UCP3 and PDK4 transcripts in the skeletal muscle of mice fed the MCFA- or LCFA-enriched HFD were similar. To further elucidate the specific effects of MCFAs, such as capric acid (C10:0), on lipid metabolism in skeletal muscles, we examined the effects of various FAs on expression of UCP3 and PDK4, in mouse C2C12 myocytes. Although palmitic acid (C16:0) and lauric acid (C12:0) significantly induced expression of both UCP3 and PDK4, capric acid (C10:0) upregulated only UCP3 expression via activation of peroxisome proliferator-activated receptor-δ. Furthermore, palmitic acid (C16:0) disturbed the insulin-induced phosphorylation of Akt, while MCFAs, including lauric (C12:0), capric (C10:0), and caprylic acid (C12:0), did not. These results suggest that capric acid (C10:0) increases the capacity for fatty acid oxidation without inhibiting glycolysis in skeletal muscle.
Yasuaki Kashino, Kaeko Murota, Namiko Matsuda, Muneaki Tomotake, Takuya Hamano, Rie Mukai and Junji Terao : Effect of Processed Onions on the Plasma Concentration of Quercetin in Rats and Humans., Journal of Food Science, Vol.80, No.11, H2597-H2602, 2015.
(Summary)
Onion is a popular source of antioxidative flavonoid quercetin and its vascular function attracts considerable attention in relation to anti-atherosclerotic effect. The present study estimated the effect of food processing on the bioavailability of onion quercetin aglycone and its glucosides provided through the consumption of onion products. The intake of a peel powder-containing meal showed a significantly higher bioavailability than the peel extract, bulb powder, bulb extract, and bulb sauté containing meals. Hence, food processing of onion peel may enhance the health impact of onion quercetin by elevating its bioavailability.
Chieko Shiota, Tomoki Abe, Nobuhiko Kawai, Ayako Ohno, Shigetada Teshima-Kondo, Hiroyo Mori, Junji Terao, Eiji Tanaka and Takeshi Nikawa : Flavones Inhibit LPS-Induced Atrogin-1/MAFbx Expression in Mouse C2C12 Skeletal Myotubes., Journal of Nutritional Science and Vitaminology, Vol.61, No.2, 188-194, 2015.
(Summary)
Muscle atrophy is a complex process that occurs as a consequence of various stress events. Muscle atrophy-associated genes (atrogenes) such as atrogin-1/MAFbx and MuRF-1 are induced early in the atrophy process, and the increase in their expression precedes the loss of muscle weight. Although antioxidative nutrients suppress atrogene expression in skeletal muscle cells, the inhibitory effects of flavonoids on inflammation-induced atrogin-1/MAFbx expression have not been clarified. Here, we investigated the inhibitory effects of flavonoids on lipopolysaccharide (LPS)-induced atrogin-1/MAFbx expression. We examined whether nine flavonoids belonging to six flavonoid categories inhibited atrogin-1/MAFbx expression in mouse C2C12 myotubes. Two major flavones, apigenin and luteolin, displayed potent inhibitory effects on atrogin-1/MAFbx expression. The pretreatment with apigenin and luteolin significantly prevented the decrease in C2C12 myotube diameter caused by LPS stimulation. Importantly, the pretreatment of LPS-stimulated myoblasts with these flavones significantly inhibited LPS-induced JNK phosphorylation in C2C12 myotubes, resulting in the significant suppression of atrogin-1/MAFbx promoter activity. These results suggest that apigenin and luteolin, prevent LPS-mediated atrogin-1/MAFbx expression through the inhibition of the JNK signaling pathway in C2C12 myotubes. Thus, these flavones, apigenin and luteolin, may be promising agents to prevent LPS-induced muscle atrophy.
Rita Cristina Orihuela Campos, Naofumi Tamaki, Rie Mukai, Makoto Fukui, Kaname Miki, Junji Terao and Hiro-O Ito : Biological impacts of resveratrol, quercetin, and N-acetylcysteine on oxidative stress in human gingival fibroblasts., Journal of Clinical Biochemistry and Nutrition, Vol.56, No.3, 220-227, 2015.
(Summary)
In periodontitis, production of reactive oxygen species (ROS) by neutrophils induces oxidative stress and deteriorates surrounding tissues. Antioxidants reduce damage caused by ROS and are used to treat diseases involving oxidative stress. This study summarizes the different effects of resveratrol, quercetin, and N-acetylcysteine (NAC) on human gingival fibroblasts (HGFs) under oxidative stress induced by hydrogen peroxide. Real-time cytotoxicity analyses reveals that resveratrol and quercetin enhanced cell proliferation even under oxidative stress. Of the antioxidants tested, resveratrol is the most effective at inhibiting ROS production. HGFs incubated with resveratrol and quercetin up-regulate the transcription of type I collagen gene after 3 h, but only resveratrol sustained this up-regulation for 24 h. A measurement of the oxygen consumption rate (OCR, mitochondrial respiration) shows that resveratrol generates the highest maximal respiratory capacity, followed by quercetin and NAC. Simultaneous measurement of OCR and the extracellular acidification rate (non-mitochondrial respiration) reveals that resveratrol and quercetin induce an increase in mitochondrial respiration when compared with untreated cells. NAC treatment consumes less oxygen and enhances more non-mitochondrial respiration. In conclusion, resveratrol is the most effective antioxidant in terms of real-time cytotoxicity analysis, reduction of ROS production, and enhancement of type I collagen synthesis and mitochondrial respiration in HGFs.
A DGpYMP peptide mimetic of tyrosine(608)-phosphorylated insulin receptor substrate-1 (IRS-1), named Cblin, was previously shown to significantly inhibit Cbl-b-mediated IRS-1 ubiquitination. In the present study, we developed N-myristoylated Cblin and investigated whether it was effective in preventing glucocorticoid-induced muscle atrophy. Using HEK293 cells overexpressing Cbl-b, IRS-1 and ubiquitin, we showed that the 50% inhibitory concentrations of Cbl-b-mediated IRS-1 ubiquitination by N-myristoylated Cblin and Cblin were 30 and 120M, respectively. Regarding the DEX-induced atrophy of C2C12 myotubes, N-myristoylated Cblin was more effective than Cblin for inhibiting the DEX-induced decreases in C2C12 myotube diameter and IRS-1 degradation. The inhibitory efficacy of N-myristoylated Cblin on IRS-1 ubiquitination in C2C12 myotubes was approximately fourfold larger than that of Cblin. Furthermore, N-myristoylation increased the incorporation of Cblin into HEK293 cells approximately 10-folds. Finally, we demonstrated that N-myristoylated Cblin prevented the wet weight loss, IRS-1 degradation, and MAFbx/atrogin-1 and MuRF-1 expression in gastrocnemius muscle of DEX-treated mice approximately fourfold more effectively than Cblin. Taken together, these results suggest that N-myristoylated Cblin prevents DEX-induced skeletal muscle atrophy in vitro and in vivo, and that N-myristoylated Cblin more effectively prevents muscle atrophy than unmodified Cblin.
Rie Hashimoto, Atsuko Sakai, Masumi Murayama, Arisa Ochi, Tomoki Abe, Katsuya Hirasaka, Ayako Ohno, Shigetada Teshima-Kondo, Hiroaki Yanagawa, Natsuo Yasui, Mikiko Inatsugi, Daisuke Doi, Masanori Takeda, Rie Mukai, Junji Terao and Takeshi Nikawa : Effects of dietary soy protein on skeletal muscle volume and strength in humans with various physical activities, The Journal of Medical Investigation : JMI, Vol.62, No.3, 177-183, 2015.
(Summary)
Background: In recent years, the number of bedridden people is rapidly increasing due to aging or lack of exercise in Japan. This problem is becoming more serious, since there is no countermeasure against it. In the present study, we designed to investigate whether dietary proteins, especially soy, had beneficial effects on skeletal muscle in 59 volunteers with various physical activities. Methods: We subjected 59 volunteers with various physical activities to meal intervention examination. Persons with low and high physical activities were divided into two dietary groups, the casein diet group and the soy diet group. They ate daily meals supplemented with 7.8 g of powdered casein or soy protein isolate every day for 30 days. Bedridden patients in hospitals were further divided into three dietary groups: the no supplementation diet group, the casein diet group and the soy diet group. They were also subjected to a blood test, a urinalysis, magnetic resonance imaging analysis and muscle strength test of the knee before and after the meal intervention study. Results: Thirty-day soy protein supplementation significantly increased skeletal muscle volume in participants with low physical activity, compared with 30-day casein protein supplementation. Both casein and soy protein supplementation increased the volume of quadriceps femoris muscle in bedridden patients. Consistently, soy protein significantly increased their extension power of the knee, compared with casein protein. Although casein protein increased skeletal muscle volume more than soy protein in bedridden patients, their muscle strength changes by soy protein supplementation were bigger than those by casein protein supplementation. Conclusions: The supplementation of soy protein would be one of the effective foods which prevent the skeletal muscle atrophy caused by immobilization or unloading. J. Med. Invest. 62: 177-183, August, 2015
Noriko Bando, 片岡 美樹, Toshiyuki Nakamura, Rie Mukai, 山岸 喬 and Junji Terao : Comparison of Isoflavone Absorption by Soybean Products in Humans, Journal of Japanese Society of Nutrition and Food Science, Vol.68, No.1, 25-29, 2015.
(Summary)
We investigated the bioavailability of soy isoflavones from processed soybean products. Five healthy male volunteers ingested soy milk, soy curd (tofu) , boiled soybeans (nimame) , or fermented soybeans (natto) in a single dose, and blood was collected 90 min later for measurement of the plasma isoflavone concentration. Each subject ingested test meals containing an isoflavone equivalent of 50 mg aglycone. The total amount of each isoflavone was determined by HPLC analysis after deconjugation of conjugated metabolites using sulfatase H-1. The concentration of glycitein was below the detection limit before and after intake of the soybean products. The concentrations of daidzein and genistein were elevated in all subjects after ingestion of all the test meals, and the concentration of genistein was higher than that of daidzein except after ingestion of fermented soybeans. Ingestion of boiled soybeans appeared to result in a higher concentration of total isoflavones (daizein and genistein) than ingestion of soy curd. These results suggest that the bioavailability of isoflavones from soybeans varies according to the type of processing.
(Keyword)
isoflavone / soybean products / bioavailability / human
Toshiyuki Nakamura, Ayako Noma and Junji Terao : Location of a-tocopherol and a-tocotrienol to heterogeneous cell membranes and inhibition of production of peroxidizied cholesterol in mouse fibroblasts., SpringerPlus, Vol.3, No.1, e550, 2014.
(Summary)
α-Tocopherol (α-T) and α-tocotrienol (α-T3) are well recognized as lipophilic antioxidants. Nevertheless, there is limited knowledge on their location in heterogeneous cell membranes. We first investigated the distribution of α-T and α-T3 to the cholesterol-rich microdomains (lipid rafts and caveolae) of heterogeneous cell membranes by incubating these antioxidants with cultured mouse fibroblasts. Levels of cellular uptake for α-T and α-T3 were adjusted to the same order, as that of the latter was much more efficient than that of the former in the cultured cells. After ultracentrifugation, α-T and α-T3 were partitioned to the microdomain fractions. When the distribution of α-T and α-T3 was further confirmed by using methyl-β-cyclodextrin (which removes cholesterol from membranes), α-T was suggested to be distributed to the microdomains (approx. 9% of the total uptake). The same treatment did not affect α-T3 content in the microdomain fractions, indicating that α-T3 is not located in these cholesterol-rich domains. However, α-T and α-T3 significantly inhibited the production of peroxidized cholesterol when cells were exposed to ultraviolet-A light. These results suggest that α-T and α-T3 can act as membranous antioxidants against photo-irradiated cholesterol peroxidation irrespective of their distribution to cholesterol-rich microdomains.
Bandaruk Yauhen, Rie Mukai and Junji Terao : Cellular uptake of quercetin and luteolin and their effects on monoamine oxidase-A in human neuroblastoma SH-SY5Y cells, Toxicology Reports, Vol.1, No.1, 639-649, 2014.
Akari Ishisaka, Rie Mukai, Junji Terao, Noriyuki Shibata and Yoshichika Kawai : Specific localization of quercetin-3-O-glucuronide in human brain., Archives of Biochemistry and Biophysics, Vol.557, 11-17, 2014.
(Summary)
In recent years, many papers have suggested that dietary flavonoids may exert beneficial effects in the brain tissue for the protection of neurons against oxidative stress and inflammation. However, the bioavailability of flavonoids across the blood-brain barrier and the localization in the brain remain controversial. Thus, we examined the localization of quercetin-3-O-glucuronide (Q3GA), a major phase-II metabolite of quercetin, in the human brain tissues with or without cerebral infarction by immunohistochemical staining using anti-Q3GA antibody. A significant immunoreactivity was observed in the epithelial cells of the choroid plexus, which constitute the structural basis of the blood-cerebrospinal fluid (CSF) barrier, and in the foamy macrophages of recent infarcts. The cellular accumulation of Q3GA was also reproduced in vitro in macrophage-like RAW264, microglial MG6, and brain capillary endothelial RBEC1. It is of interest that a common feature of these cell lines is the deconjugation of Q3GA, resulting in the cellular accumulation of non-conjugated quercetin and the methylated forms. We then examined the anti-inflammatory activity of Q3GA and the deconjugated forms in the lipopolysaccharide-stimulated macrophage cells and revealed that the deconjugated forms (quercetin and a methylated form isorhamnetin), but not Q3GA itself, exhibited inhibitory effects on the inflammatory responses through attenuation of the c-Jun N-terminal kinase pathway. These results suggested that a quercetin glucuronide can pass through the blood-brain barrier, perhaps the CSF barrier, accumulate in specific types of cells, such as macrophages, and act as anti-inflammatory agents in the brain through deconjugation into the bioactive non-conjugated forms.
Junji Terao : Cholesterol hydroperoxides and their degradation mechanism., Sub-cellular Biochemistry, Vol.77, No.1, 83-91, 2014.
(Summary)
Cholesterol is one of the oxidizable lipids constituting biomembranes and plasma lipoproteins. Cholesterol hydroperoxides (Chol-OOH) are the primary products if cholesterol is subjected to attack by reactive oxygen species. In particular, singlet molecular oxygen reacts with cholesterol to yield cholesterol 5α-hydroperoxide as the major hydroperoxide species. Chol-OOH may accumulate in biological systems because of its resistance to glutathione-dependent enzymatic detoxification reactions. Their degradation products (including hydroxycholesterol and 7-ketocholesterol) participate in the pathophysiological functions of oxysterols. Highly reactive cholesterol 5,6-secosterol present in atherosclerotic lesions can be derived from the degradation of cholesterol 5α-hydroperoxide. Chol-OOH themselves may affect the lipid rafts of biomembranes, thereby leading to the modification of signal transduction pathways.
(Keyword)
cholesterol / Free Radicals / hydrogen peroxide / Ketocholesterols / liposomes / reactive oxygen species / signal transduction / Singlet Oxygen
Akari Ishisaka, Kyuichi Kawabata, Satomi Miki, Yuko Shiba, Shoko Minekawa, Tomomi Nishikawa, Rie Mukai, Junji Terao and Yoshichika Kawai : Mitochondrial dysfunction leads to deconjugation of quercetin glucuronides in inflammatory macrophages., PLoS ONE, Vol.8, No.11, e80843, 2013.
(Summary)
Dietary flavonoids, such as quercetin, have long been recognized to protect blood vessels from atherogenic inflammation by yet unknown mechanisms. We have previously discovered the specific localization of quercetin-3-O-glucuronide (Q3GA), a phase II metabolite of quercetin, in macrophage cells in the human atherosclerotic lesions, but the biological significance is poorly understood. We have now demonstrated the molecular basis of the interaction between quercetin glucuronides and macrophages, leading to deconjugation of the glucuronides into the active aglycone. In vitro experiments showed that Q3GA was bound to the cell surface proteins of macrophages through anion binding and was readily deconjugated into the aglycone. It is of interest that the macrophage-mediated deconjugation of Q3GA was significantly enhanced upon inflammatory activation by lipopolysaccharide (LPS). Zymography and immunoblotting analysis revealed that -glucuronidase is the major enzyme responsible for the deglucuronidation, whereas the secretion rate was not affected after LPS treatment. We found that extracellular acidification, which is required for the activity of -glucuronidase, was significantly induced upon LPS treatment and was due to the increased lactate secretion associated with mitochondrial dysfunction. In addition, the -glucuronidase secretion, which is triggered by intracellular calcium ions, was also induced by mitochondria dysfunction characterized using antimycin-A (a mitochondrial inhibitor) and siRNA-knockdown of Atg7 (an essential gene for autophagy). The deconjugated aglycone, quercetin, acts as an anti-inflammatory agent in the stimulated macrophages by inhibiting the c-Jun N-terminal kinase activation, whereas Q3GA acts only in the presence of extracellular -glucuronidase activity. Finally, we demonstrated the deconjugation of quercetin glucuronides including the sulfoglucuronides in vivo in the spleen of mice challenged with LPS. These results showed that mitochondrial dysfunction plays a crucial role in the deconjugation of quercetin glucuronides in macrophages. Collectively, this study contributes to clarifying the mechanism responsible for the anti-inflammatory activity of dietary flavonoids within the inflammation sites.
Rie Mukai, Yutaka Fujikura, Kaeko Murota, Shoko Minekawa, Naoko Matsui, Hisao Nemoto and Junji Terao : Prenylation enhances quercetin uptake and reduces efflux in Caco-2 cells and enhances tissue accumulation in mice fed long-term., The Journal of Nutrition, Vol.143, No.10, 1558-1564, 2013.
(Summary)
Prenyl flavonoids are widely distributed in plant foods and have attracted appreciable attention in relation to their potential benefits for human health. Prenylation may enhance the biological functions of flavonoids by introducing hydrophobic properties in their basic structures. Previously, we found that 8-prenyl naringenin exerted a greater preventive effect on muscle atrophy than nonprenylated naringenin in a mouse model. Here, we aimed to estimate the effect of prenylation on the bioavailability of dietary quercetin (Q). The cellular uptake of 8-prenyl quercetin (PQ) and Q in Caco-2 cells and C2C12 myotube cells was examined. Prenylation significantly enhanced the cellular uptake by increasing the lipophilicity in both cell types. In Caco-2 cells, efflux of PQ to the basolateral side was <15% of that of Q, suggesting that prenylation attenuates transport from the intestine to the circulation. After intragastric administration of PQ or Q to mice or rats, the area under the concentration-time curve for PQ in plasma and lymph was 52.5% and 37.5% lower than that of Q, respectively. PQ and its O-methylated form (MePQ) accumulated at much higher amounts than Q and O-methylated Q in the liver (Q: 3400%; MePQ: 7570%) and kidney (Q: 385%; MePQ: 736%) of mice after 18 d of feeding. These data suggest that prenylation enhances the accumulation of Q in tissues during long-term feeding, even though prenylation per se lowers its intestinal absorption from the diet.
Kaeko Murota, Rainer Cermak, Junji Terao and Siegfried Wolffram : Influence of fatty acid patterns on the intestinal absorption pathway of quercetin in thoracic lymph duct-cannulated rats., British Journal of Nutrition, Vol.109, No.12, 2147-2153, 2013.
(Summary)
Since it is known that dietary fats improve the bioavailability of the flavonol quercetin, we purposed to investigate whether this effect is due to increased lymphatic transport of quercetin. In rats with implanted catheters in the thoracic lymph duct, we administered quercetin into the duodenum with TAG emulsions containing either long-chain fatty acids (LCT) or medium-chain fatty acids (MCT). Controls received quercetin together with a glucose solution. LCT administration increased the lymphatic output of quercetin (19.1 (SEM 1.2) nmol/8 h) as well as the lymph-independent bioavailability of the flavonol, determined as area under the plasma concentration curve (1091 (SEM 142) microM x min). Compared with glucose administration, MCT neither increased the lymphatic output (12.3 (SEM 1.5) nmol/8 h) nor the bioavailability of quercetin (772 (SEM 99) microM x min) significantly (glucose group: 9.8 (SEM 1.5) nmol/8 h and 513 (SEM 55) microM x min, respectively). Because LCT are released within chylomicrons into the intestinal lymph while MCT are mainly released into the portal blood, we conclude from the present results that dietary fats that are mainly composed of LCT improve quercetin bioavailability by increasing its transport via the lymph, thereby circumventing hepatic first-pass metabolism of the flavonol. In addition, LCT could enhance quercetin absorption by improving its solubility in the intestinal tract.
(Keyword)
analysis of variance / Animals / Area Under Curve / Biological Availability / Biological Transport / Catheterization / Chylomicrons / Fatty Acids / Intestinal Absorption / Lymph / Male / Quercetin / Rats / Rats, Wistar / Triglycerides
Toshiyuki Nakamura, Ayako Noma, Sachiko Shimada, Nanase Ishii, Noriko Bando, Yoshichika Kawai and Junji Terao : Non-selective distribution of isomeric cholesterol hydroperoxides to microdomains in cell membranes and activation of matrix metalloproteinase activity in a model of dermal cells., Chemistry and Physics of Lipids, Vol.174, 17-23, 2013.
(Summary)
Cholesterol hydroperoxides (ChOOHs) are included as lipid peroxidation products in the skin exposed to ultraviolet (UV) light irradiation. They may exert physicochemical actions affecting biomembrane rigidity because cholesterol is one of the major components of cell membranes. We investigated the distribution of isomeric ChOOHs in heterogeneous cell membranes with different lipid profiles using mouse fibroblast NIH-3T3 cells as a model of the dermis. Before and after UVA irradiation in the presence of hematoporphyrin, cell membranes were partitioned to microdomains (lipid rafts and caveolae) containing a higher amount of cholesterol and non-microdomains (containing a lower amount of cholesterol) by ultracentrifugation. By a combination of diphenylpyrenylphosphine-thin-layer chromatography blotting analyses and gas chromatography-electron ionization-mass spectrometry/selected ion monitoring analyses, ChOOH isomers were determined as their trimethylsilyloxyl derivatives. Cholesterol 5α-, 7α- and 7β-hydroperoxide were found as isomeric ChOOHs before irradiation. The amounts of the three ChOOH isomers increased significantly after photoirradiation for 2h. No difference was observed between microdomains and non-microdomains with regard to the ratio of the amounts of isomeric ChOOHs to that of cholesterol, suggesting that these ChOOH isomers were distributed equally in both parts depending on cholesterol content. When cells were treated with a purified mixture of ChOOH isomers, cell membranes incorporated ChOOHs into microdomains as well as non-microdomains evenly. Cellular matrix metalloproteinase-9 (MMP-9) activity was elevated by treatment with the purified mixture of ChOOH isomers. These results strongly suggest that ChOOHs accumulate in cell membranes irrespective of the heterogeneous microstructure and promote MMP activity if dermal cells are exposed to photodynamic actions.
Tomoki Abe, Shohei Kohno, Tomonari Yama, Arisa Ochi, Takuro Suto, Katsuya Hirasaka, Ayako Ohno, Shigetada Teshima-Kondo, Yuushi Okumura, Motoko Oarada, Inho Choi, Rie Mukai, Junji Terao and Takeshi Nikawa : Soy Glycinin Contains a Functional Inhibitory Sequence against Muscle-Atrophy-Associated Ubiquitin Ligase Cbl-b., International Journal of Endocrinology, Vol.2013, 907565, 2013.
(Summary)
Background. Unloading stress induces skeletal muscle atrophy. We have reported that Cbl-b ubiquitin ligase is a master regulator of unloading-associated muscle atrophy. The present study was designed to elucidate whether dietary soy glycinin protein prevents denervation-mediated muscle atrophy, based on the presence of inhibitory peptides against Cbl-b ubiquitin ligase in soy glycinin protein. Methods. Mice were fed either 20% casein diet, 20% soy protein isolate diet, 10% glycinin diet containing 10% casein, or 20% glycinin diet. One week later, the right sciatic nerve was cut. The wet weight, cross sectional area (CSA), IGF-1 signaling, and atrogene expression in hindlimb muscles were examined at 1, 3, 3.5, or 4 days after denervation. Results. 20% soy glycinin diet significantly prevented denervation-induced decreases in muscle wet weight and myofiber CSA. Furthermore, dietary soy protein inhibited denervation-induced ubiquitination and degradation of IRS-1 in tibialis anterior muscle. Dietary soy glycinin partially suppressed the denervation-mediated expression of atrogenes, such as MAFbx/atrogin-1 and MuRF-1, through the protection of IGF-1 signaling estimated by phosphorylation of Akt-1. Conclusions. Soy glycinin contains a functional inhibitory sequence against muscle-atrophy-associated ubiquitin ligase Cbl-b. Dietary soy glycinin protein significantly prevented muscle atrophy after denervation in mice.
Mari Kotosai, Sachiko Shimada, Mai Kanda, Namiko Matsuda, Keiko Sekido, Yoshibumi Shimizu, Akira Tokumura, Toshiyuki Nakamura, Kaeko Murota, Yoshichika Kawai and Junji Terao : Plasma HDL reduces nonesterified fatty acid hydroperoxides originating from oxidized LDL., Lipids, Vol.48, No.6, 569-578, 2013.
(Summary)
The antioxidant property of plasma high-density lipoprotein (HDL) is thought to be involved in potential anti-atherogenic effects but the exact mechanism is not known. We aimed to reveal the contribution of HDL on the elimination of lipid hydroperoxides (LOOH) derived from oxidized low-density lipoprotein (LDL). Oxidized LDL prepared by copper ion-induced oxidation contained nonesterified fatty acid hydroperoxides (FFA-OOH) and lysophosphatidylcholine (lysoPtdCho), in addition to cholesteryl ester hydroperoxides (CE-OOH) and phosphatidylcholine hydroperoxides (PtdCho-OOH). A platelet-activating factor-acetylhydrolase (PAF-AH) inhibitor suppressed formation of FFA-OOH and lysoPtdCho in oxidized LDL. Among LOOH species, FFA-OOH was preferentially reduced by incubating oxidized LDL with HDL. HDL exhibited selective FFA-OOH reducing ability if it was mixed with a liposomal solution containing FFA-OOH, CE-OOH and PtdCho-OOH. Two-electron reduction of the hydroperoxy group to the hydroxy group was confirmed by the formation of 13-hydroxyoctadecadienoic acid from 13-hydroperoxyoctadecadienoic acid in HPLC analyses. This reducing effect was also found in apolipoprotein A-1 (apoA-1). FFA-OOH released from PtdCho-OOH due to PAF-AH activity in oxidized LDL undergo two-electron reduction by the reducing ability of apoA1 in HDL. This preferential reduction of FFA-OOH may participate in the mechanism of the antioxidant property of HDL.
Kohta Ohnishi, Shinya Ohkura, Erina Nakahata, Akari Ishisaka, Yoshichika Kawai, Junji Terao, Taiki Mori, Takeshi Ishii, Tsutomu Nakayama, Noriyuki Kioka, Yasutaka Ikeda, Minoru Akiyama, Kazuhiro Irie, Akira Murakami and Shinya Matsumoto : Non-specific protein modification by a phytochemical induce heat shock response for self-defense., PLoS ONE, Vol.8, No.3, e58641, 2013.
(Summary)
Accumulated evidence shows that some phytochemicals provide beneficial effects for human health. Recently, a number of mechanistic studies have revealed that direct interactions between phytochemicals and functional proteins play significant roles in exhibiting their bioactivities. However, their binding selectivities to biological molecules are considered to be lower due to their small and simple structures. In this study, we found that zerumbone, a bioactive sesquiterpene, binds to numerous proteins with little selectivity. Similar to heat-denatured proteins, zerumbone-modified proteins were recognized by heat shock protein 90, a constitutive molecular chaperone, leading to heat shock factor 1-dependent heat shock protein induction in hepa1c1c7 mouse hepatoma cells. Furthermore, oral administration of this phytochemical up-regulated heat shock protein expressions in the livers of Sprague-Dawley rats. Interestingly, pretreatment with zerumbone conferred a thermoresistant phenotype to hepa1c1c7 cells as well as to the nematode Caenorhabditis elegans. It is also important to note that several phytochemicals with higher hydrophobicity or electrophilicity, including phenethyl isothiocyanate and curcumin, markedly induced heat shock proteins, whereas most of the tested nutrients did not. These results suggest that non-specific protein modifications by xenobiotic phytochemicals cause mild proteostress, thereby inducing heat shock response and leading to potentiation of protein quality control systems. We considered these bioactivities to be xenohormesis, an adaptation mechanism against xenobiotic chemical stresses. Heat shock response by phytochemicals may be a fundamental mechanism underlying their various bioactivities.
Tomoki Abe, Katsuya Hirasaka, Sachiko Kagawa, Shohei Kohno, Arisa Ochi, Kenro Utsunomiya, Atsuko Sakai, Ayako Maita, Shigetada Teshima-Kondo, Yuushi Okumura, Motoko Oarada, Yoichi Maekawa, Junji Terao, Edward M. Mills and Takeshi Nikawa : Cbl-b is a critical regulator of macrophage activation associated with obesity-induced insulin resistance in mice., Diabetes, Vol.62, No.6, 1957-1969, 2013.
(Summary)
We previously reported the potential involvement of casitas B-cell lymphoma-b (Cbl-b) in aging-related murine insulin resistance. Because obesity also induces macrophage recruitment into adipose tissue, we elucidated here the role of Cbl-b in obesity-related insulin resistance. Cbl-b(+/+) and Cbl-b(-/-) mice were fed a high-fat diet (HFD) and then examined for obesity-related changes in insulin signaling. The HFD caused recruitment of macrophages into adipose tissue and increased inflammatory reaction in Cbl-b(-/-) compared with Cbl-b(+/+) mice. Peritoneal macrophages from Cbl-b(-/-) mice and Cbl-b-overexpressing RAW264.7 macrophages were used to examine the direct effect of saturated fatty acids (FAs) on macrophage activation. In macrophages, Cbl-b suppressed saturated FA-induced Toll-like receptor 4 (TLR4) signaling by ubiquitination and degradation of TLR4. The physiological role of Cbl-b in vivo was also examined by bone marrow transplantation and Eritoran, a TLR4 antagonist. Hematopoietic cell-specific depletion of the Cbl-b gene induced disturbed responses on insulin and glucose tolerance tests. Blockade of TLR4 signaling by Eritoran reduced fasting blood glucose and serum interleukin-6 levels in obese Cbl-b(-/-) mice. These results suggest that Cbl-b deficiency could exaggerate HFD-induced insulin resistance through saturated FA-mediated macrophage activation. Therefore, inhibition of TLR4 signaling is an attractive therapeutic strategy for treatment of obesity-related insulin resistance.
Katsuya Hirasaka, Tasuku Maeda, Chika Ikeda, Marie Haruna, Arisa Ochi, Rie Mukai, Motoko Oarada, Shigetada Kondo, Ayako Ohno, Yuushi Okumura, Junji Terao and Takeshi Nikawa : Isoflavones derived from soy beans prevent MuRF1-mediated muscle atrophy in C2C12 myotubes through SIRT1 activation., Journal of Nutritional Science and Vitaminology, Vol.59, No.4, 317-324, 2013.
(Summary)
Proinflammatory cytokines are factors that induce ubiquitin-proteasome-dependent proteolysis in skeletal muscle, causing muscle atrophy. Although isoflavones, as potent antioxidative nutrients, have been known to reduce muscle damage during the catabolic state, the non-antioxidant effects of isoflavones against muscle atrophy are not well known. Here we report on the inhibitory effects of isoflavones such as genistein and daidzein on muscle atrophy caused by tumor necrosis factor (TNF)- treatment. In C2C12 myotubes, TNF- treatment markedly elevated the expression of the muscle-specific ubiquitin ligase MuRF1, but not of atrogin-1, leading to myotube atrophy. We found that MuRF1 promoter activity was mediated by acetylation of p65, a subunit of NFB, a downstream target of the TNF- signaling pathway; increased MuRF1 promoter activity was abolished by SIRT1, which is associated with deacetylation of p65. Of interest, isoflavones induced expression of SIRT1 mRNA and phosphorylation of AMP kinase, which is well known to stimulate SIRT1 expression, although there was no direct effect on SIRT1 activation. Moreover, isoflavones significantly suppressed MuRF1 promoter activity and myotube atrophy induced by TNF- in C2C12 myotubes. These results suggest that isoflavones suppress myotube atrophy in skeletal muscle cells through activation of SIRT1 signaling. Thus, the efficacy of isoflavones could provide a novel therapeutic approach against inflammation-related muscle atrophy.
A Rodriguez-Mateos, Akari Ishisaka, Kazuaki Mawatari, Alberto Vidal-Diez, Jeremy Spencer and Junji Terao : Blueberry intervention improves vascular reactivity and lowers blood pressure in high fat, high cholesterol fed rats, British Journal of Nutrition, Vol.109, No.10, 1746-1754, 2013.
(Summary)
Growing evidence suggests that intake of flavonoid-containing foods may exert cardiovascular benefits in human subjects. We have investigated the effects of a 10-week blueberry (BB) supplementation on blood pressure (BP) and vascular reactivity in rats fed a high-fat/high-cholesterol diet, known to induce endothelial dysfunction. Rats were randomly assigned to follow a control chow diet, a chow diet supplemented with 2 % (w/w) BB, a high-fat diet (10 % lard; 0·5 % cholesterol) or the high fat plus BB for 10 weeks. Rats supplemented with BB showed significant reductions in systolic BP (SBP) of 11 and 14 %, at weeks 8 and 10, respectively, relative to rats fed the control chow diet (week 8 SBP: 107·5 (SEM 4·7) v. 122·2 (SEM 2·1) mmHg, P= 0·018; week 10 SBP: 115·0 (SEM 3·1) v. 132·7 (SEM 1·5) mmHg, P< 0·0001). Furthermore, SBP was reduced by 14 % in rats fed with the high fat plus 2 % BB diet at week 10, compared to those on the high-fat diet only (SBP: 118·2 (SEM 3·6) v. 139·5 (SEM 4·5) mmHg, P< 0·0001). Aortas harvested from BB-fed animals exhibited significantly reduced contractile responses (to L-phenylephrine) compared to those fed the control chow or high-fat diets. Furthermore, in rats fed with high fat supplemented with BB, aorta relaxation was significantly greater in response to acetylcholine compared to animals fed with the fat diet. These data suggest that BB consumption can lower BP and improve endothelial dysfunction induced by a high fat, high cholesterol containing diet.
Yauhen Bandaruk, Rie Mukai, Tomoyuki Kawamura, Hisao Nemoto and Junji Terao : Evaluation of the inhibitory effects of quercetin-related flavonoids and tea catechins on the monoamine oxidase-A reaction in mouse brain mitochondria., Journal of Agricultural and Food Chemistry, Vol.60, No.41, 10270-10277, 2012.
(Summary)
Quercetin, a typical dietary flavonoid, is thought to exert antidepressant effects by inhibiting the monoamine oxidase-A (MAO-A) reaction, which is responsible for regulation of the metabolism of the neurotransmitter 5-hydroxytryptamine (5-HT) in the brain. This study compared the MAO-A inhibitory activity of quercetin with those of O-methylated quercetin (isorhamnetin, tamarixetin), luteolin, and green tea catechins ((-)-epicatechin, (-)-epicatechin gallate, (-)-epigallocatechin, and (-)-epigallocatechin gallate) by measuring the formation of the oxidative deamination product of 5-HT, 5-hydroxyindole aldehyde (5-HIAL), in mouse brain mitochondria. Quercetin was inferior to luteolin in the inhibition of MAO-A activity, whereas isorhamnetin, tamarixetin, and tea catechins scarcely exerted inhibitory activity. Quercetin did not affect MAO-A activity in mouse intestinal mitochondria, indicating that it does not evoke side effects on the metabolism of dietary monoamines in the gut. These data suggest that quercetin is a weak (but safe) MAO-A inhibitor in the modulation of 5-HT levels in the brain.
Rie Mukai, Hitomi Horikawa, Yutaka Fujikura, Tomoyuki Kawamura, Hisao Nemoto, Takeshi Nikawa and Junji Terao : Prevention of disuse muscle atrophy by dietary ingestion of 8-prenylnaringenin in denervated mice, PLoS ONE, Vol.7, No.9, e45048, 2012.
(Summary)
Flavonoids have attracted considerable attention in relation to their effects upon health. 8-Prenylnaringenin (8-PN) is found in the common hop (Humulus lupulus) and assumed to be responsible for the health impact of beer consumption. We wanted to clarify the effects of prenylation on the physiological functions of dietary flavonoids by comparing the effects of 8-PN with that of intact naringenin in the prevention of disuse muscle atrophy using a model of denervation in mice. Consumption of 8-PN (but not naringenin) prevented loss of weight in the gastrocnemius muscle further supported by the lack of induction of the protein content of a key ubiquitin ligase involved in muscle atrophy, atrogin-1, and by the activation of Akt phosphorylation. 8-PN content in the gastrocnemius muscle was tenfold higher than that of naringenin. These results suggested that, compared with naringenin, 8-PN was effectively concentrated into skeletal muscle to exert its preventive effects upon disuse muscle atrophy. It is likely that prenylation generates novel functions for 8-PN by enhancing its accumulation into muscle tissue through dietary intake.
Rie Mukai, Kyuichi Kawabata, Seiko Otsuka, Akari Ishisaka, Yoshichika Kawai, Zai-Si Ji, Hiroshi Tsuboi and Junji Terao : Effect of quercetin and its glucuronide metabolite upon 6-hydorxydopamine-induced oxidative damage in Neuro-2a cells., Free Radical Research, Vol.46, No.8, 1019-1028, 2012.
(Summary)
Quercetin is ubiquitously distributed in plant foods. This antioxidative polyphenol is mostly converted to conjugated metabolites in the body. Parkinson disease (PD) has been suggested to be related to oxidative stress derived from abnormal dopaminergic activity. We evaluated if dietary quercetin contributes to the antioxidant network in the central nervous system from the viewpoint of PD prevention. A neurotoxin, 6-hydroxydopamine (6-OHDA), was used as a model of PD. 6-OHDA-induced H(2)O(2) production and cell death in mouse neuroblastoma, Neuro-2a. Quercetin aglycone suppressed 6-OHDA-induced H(2)O(2) production and cell death, although aglycone itself reduced cell viability at higher concentration. Quercetin 3-O-β-d-glucuronide (Q3GA), which is an antioxidative metabolite of dietary quercetin, was little incorporated into the cell resulting in neither suppression of 6-OHDA-induced cell death nor reduction of cell viability. Q3GA was found to be deconjugated to quercetin by microglial MG-6 cells. These results indicate that quercetin metabolites should be converted to their aglycone to exert preventive effect on damage to neuronal cells.
Ichiro Kunitsugu, Masayuki Okuda, Natsuko Murakami, Michio Hashimoto, Rintaro Yamanishi, Noriko Bando, Satoshi Sasaki, Junji Terao, Shinichi Sugiyama and Tatsuya Hobara : Self-reported seafood intake and atopy in Japanese school-aged children., Pediatrics International, Vol.54, No.2, 233-237, 2012.
(Summary)
The effects of fish consumption and n-3 poly-unsaturated fatty acid (PUFA) levels on atopic disorders are inconsistent in previous reports, but few studies have investigated the effects of both fish and n-3 PUFA. The aim of the present study was to investigate whether erythrocyte fatty acids and the consumption of fish are associated with atopic diseases in pre- and early adolescents. A total of 135 students with eczema, 136 students with asthma, and 137 healthy control students were selected from fifth and eighth grades in Shunan, Japan. Atopic disorders and dietary intake were evaluated with questionnaires, and total serum IgE was measured using an enzyme-linked immunosorbent assay. In addition, erythrocyte membrane levels of PUFA were assessed via gas chromatography. Total IgE was significantly elevated in the atopic subjects (P < 0.001). The intake of fatty and dried fish or seafood was significantly associated with eczema (odds ratios of the highest quartiles: 0.46, 95% confidence interval (95%CI): 0.22-0.94; 0.34, 95%CI: 0.16-0.71, respectively). Additionally, only erythrocyte eicosapentaenoic acid (EPA) level had a negative association with eczema (P= 0.048). For asthma, the effect of fish consumption was not significant. Fish consumption was related to a low prevalence of eczema, but not asthma in Japanese pre- and early adolescents. EPA may be involved in this mechanism.
Shohei Kohno, Yui Yamashita, Tomoki Abe, Katsuya Hirasaka, Motoko Oarada, Ayako Ohno, Shigetada Teshima-Kondo, Akira Higashibata, Inho Choi, Edward M. Mills, Yuushi Okumura, Junji Terao and Takeshi Nikawa : Unloading stress disturbs muscle regeneration through perturbed recruitment and function of macrophages., Journal of Applied Physiology, Vol.112, No.10, 1773-1782, 2012.
(Summary)
Skeletal muscle is one of the most sensitive tissues to mechanical loading, and unloading inhibits the regeneration potential of skeletal muscle after injury. This study was designed to elucidate the specific effects of unloading stress on the function of immunocytes during muscle regeneration after injury. We examined immunocyte infiltration and muscle regeneration in cardiotoxin (CTX)-injected soleus muscles of tail-suspended (TS) mice. In CTX-injected TS mice, the cross-sectional area of regenerating myofibers was smaller than that of weight-bearing (WB) mice, indicating that unloading delays muscle regeneration following CTX-induced skeletal muscle damage. Delayed infiltration of macrophages into the injured skeletal muscle was observed in CTX-injected TS mice. Neutrophils and macrophages in CTX-injected TS muscle were presented over a longer period at the injury sites compared with those in CTX-injected WB muscle. Disturbance of activation and differentiation of satellite cells was also observed in CTX-injected TS mice. Further analysis showed that the macrophages in soleus muscles were mainly Ly-6C-positive proinflammatory macrophages, with high expression of tumor necrosis factor- and interleukin-1, indicating that unloading causes preferential accumulation and persistence of proinflammatory macrophages in the injured muscle. The phagocytic and myotube formation properties of macrophages from CTX-injected TS skeletal muscle were suppressed compared with those from CTX-injected WB skeletal muscle. We concluded that the disturbed muscle regeneration under unloading is due to impaired macrophage function, inhibition of satellite cell activation, and their cooperation.
Hiroko Takumi, Hiroyasu Nakamura, Terumi Simizu, Ryoko Harada, Takashi Kometani, Tomonori Nadamoto, Rie Mukai, Kaeko Murota, Yoshichika Kawai and Junji Terao : Bioavailability of orally administered water-dispersible hesperetin and its effect on peripheral vasodilatation in human subjects: implication of endothelial functions of plasma conjugated metabolites., Food & Function, Vol.3, No.4, 389-398, 2012.
(Summary)
Hesperetin is an aglycone of citrus flavonoids and is expected to exert a vasodilatation effect in vivo. We developed water-dispersible hesperetin by the process of micronization to enhance the bioavailability of hesperetin. This study aimed to assess the effect of this process on the bioavailability of hesperetin and to estimate its efficiency on vasodilatation-related functions using endothelial cells in vitro and a human volunteer study at a single dose in vivo. We found that water-dispersible hesperetin was absorbed rapidly, with its maximum plasma concentration (C(max)) being 10.2 ± 1.2 μM, and that the time to reach C(max), which is within 1 h if 150 mg of this preparation was orally administered in humans. LC-MS analyses of the plasma at C(max) demonstrated that hesperetin accumulated in the plasma as hesperetin 7-O-β-D-glucuronide (Hp7GA), hesperetin 3'-O-β-D-glucuronide (Hp3'GA) and hesperetin sulfate exclusively. Similar to hesperetin, Hp7GA enhanced nitric oxide (NO) release by inhibiting nicotinamide adenine dinucleotide phosphate-oxidase (NADPH oxidase) activity in a human umbilical vein endothelial cell culture system, indicating that plasma hesperetin metabolites can improve vasodilatation in the vascular system. A volunteer study using women with cold sensitivity showed that a single dose of water-dispersible hesperetin was effective on peripheral vasodilatation.These results strongly suggest that rapid accumulation with higher plasma concentration enables hesperetin to exert a potential vasodilatation effect by the endothelial action of its plasma metabolites. Water-dispersible hesperetin may be useful to improve the health effect of dietary hesperetin.
Hiroko Takumi, Rie Mukai, Sawako Ishiduka, Takashi Kometani and Junji Terao : Tissue distribution of hesperetin in rats after a dietary intake., Bioscience, Biotechnology, and Biochemistry, Vol.75, No.8, 1608-1610, 2011.
(Summary)
Hesperetin, the aglycone of hesperidin present in citrus fruits, possesses various biological activities. We assessed the tissue distribution of hesperetin in rats fed with a 0.2% hesperetin diet for 4 weeks. Its highest concentration was found in the liver, and the second highest was in the aorta. The aorta is assumed to be one of the main target tissues of hesperetin for exerting its functions.
Keisuke Ishizawa, Masanori Yoshizumi, Yoshichika Kawai, Junji Terao, Yoshitaka Kihira, Yasumasa Ikeda, Shuhei Tomita, Kazuo Minakuchi, Koichiro Tsuchiya and Toshiaki Tamaki : Pharmacology in health food: Metabolism of quercetin in vivo and its protective effect against arteriosclerosis, Journal of Pharmacological Sciences, Vol.115, No.4, 466-470, 2011.
(Summary)
Quercetin, a member of the bioflavonoids family, has been proposed to have anti-atherogenic, anti-inflammatory, and anti-hypertensive properties leading to the beneficial effects against cardiovascular diseases. It was recently demonstrated that quercetin 3-O-β-D-glucuronide (Q3GA) is one of the major quercetin conjugates in human plasma, in which the aglycone could not be detected. Although most of the in vitro pharmacological studies have been carried out using only the quercetin aglycone form, experiments using Q3GA would be important to discover the preventive mechanisms of cardiovascular diseases by quercetin in vivo. Therefore we examined the effects of the chemically synthesized Q3GA, as an in vivo form, on vascular smooth muscle cell (VSMC) disorders related to the progression of arteriosclerosis. Platelet-derived growth factor-induced cell migration and proliferation were inhibited by Q3GA in VSMCs. Q3GA attenuated angiotensin II-induced VSMC hypertrophy via its inhibitory effect on JNK and the AP-1 signaling pathway. Q3GA scavenged 1,1-diphenyl-2-picrylhydrazyl radical measured by the electron paramagnetic resonance method. In addition, immunohistochemical studies with monoclonal antibody 14A2 targeting the Q3GA demonstrated that the positive staining specifically accumulates in human atherosclerotic lesions, but not in the normal aorta. These findings suggest Q3GA would be an active metabolite of quercetin in plasma and may have preventative effects on arteriosclerosis relevant to VSMC disorders.
(Keyword)
Animals / Antioxidants / Arteriosclerosis / Cell Movement / Cell Proliferation / Drug Evaluation, Preclinical / Free Radicals / Health Food / Humans / Hypertrophy / Muscle, Smooth, Vascular / Quercetin / Signal Transduction
Saki Yoshino, Aya Hara, Hiroyuki Sakakibara, Kyuichi Kawabata, Akira Tokumura, Akari Ishisaka, Yoshichika Kawai and Junji Terao : Effect of quercetin and glucuronide metabolites on the monoamine oxidase-A reaction in mouse brain mitochondria., Nutrition, 2011.
(Summary)
OBJECTIVE: Quercetin is a flavonoid found in plant foods and herbal medicines. It possesses antidepressant-like effects in forced swimming test-loaded rodents. We wanted to clarify the mechanism of action of dietary quercetin for exerting antidepressant-like effects. The effect of quercetin and its antioxidative metabolite quercetin 3-glucuronide (Q3GA) on the activity of mouse brain mitochondrial monoamine oxidase-A (MAO-A) was evaluated by measuring the deamination product of serotonin, 5-hydroxyindole acetaldehyde (5-HIAL). METHODS: An ultraviolet high-performance liquid chromatographic analysis was applied to measure the 5-HIAL generated by the reaction of MAO-A with serotonin. The inhibitory effect of quercetin and Q3GA on mitochondrial MAO-A activity was estimated by the content of 5-HIAL and hydrogen peroxide accompanied by the MAO-A reaction. RESULTS: Quercetin (but not Q3GA) decreased the production of 5-HIAL by MAO-A activity. Q3GA inhibited the generation of hydrogen peroxide from the MAO-A reaction with serotonin. A periodic forced swimming test in mice increased brain mitochondrial MAO-A activity. Brain mitochondrial MAO-A activity was decreased in mice administered quercetin for 7 d, but its effect was much weaker than that of the selective MAO-A inhibitor clorgyline. CONCLUSION: Quercetin is effective in the modulation of serotonergic activity by attenuating mitochondrial MAO-A activity in the brain. Its antioxidative metabolite Q3GA attenuates oxidative stress by interrupting the generation of hydrogen peroxide accompanying the MAO-A reaction.
Deficiency of the Cbl-b ubiquitin ligase gene activates macrophages in mice. This study aimed to elucidate the pathophysiological roles of macrophages in muscle degeneration/regeneration in Cbl-b-deficient mice. We examined immune cell infiltration and cytokine expression in cardiotoxin-injected tibialis anterior muscle of Cbl-b-deficient mice. Ablation of the Cbl-b gene expression delayed regeneration of cardiotoxin-induced skeletal muscle damage compared with wild-type mice. CD8-positive T cells were still present in the damaged muscle on day 14 after cardiotoxin injection in Cbl-b-deficient mice, but there was dispersal of the same cells over that time-frame in wild-type mice. Infiltrating macrophages in Cbl-b-deficient mice showed strong expression of RANTES (regulated-on-activation, normal T cell expressed and secreted), a chemokine for CD8-positive T cells. In turn, a neutralizing antibody against RANTES significantly suppressed the infiltration of CD8-positive T cells into the muscle, resulting in restoration of the disturbed muscle regeneration. Cbl-b is an important regulatory factor for cytotoxic T-cell infiltration via RANTES production in macrophages.
Junji Terao, Kaeko Murota and Yoshichika Kawai : Conjugated quercetin glucuronides as bioactive metabolites and precursors of aglycone in vivo, Food & Function, Vol.2, No.1, 11-17, 2011.
(Summary)
Quercetin is a typical anti-oxidative flavonoid ubiquitously distributed in vegetables. It is likely to act as a bioactive compound by exerting reactive oxygen species (ROS)-scavenging activity and/or binding to specific proteins such as oxidative enzymes and transcriptional factors in signal transduction pathways. Its absorption and metabolism (as well as its molecular targets) have been extensively explored from the viewpoint of its potential for disease prevention. It is known that glucuronide and/or sulfate conjugates with or without O-methylation exclusively circulate in the human bloodstream after intake of a quercetin-containing diet. We propose that glucuronide conjugates of quercetin function not only as detoxified metabolites but hydrophilic bioactive agents to various ROS-generating systems and precursors of hydrophobic aglycone. Quercetin aglycone is assumed to emerge in the target site by the action of β-glucuronidase activity under oxidative stress such as inflammation. The cardiovascular system and central nervous system seem to be the major targets of conjugated quercetin glucuronides circulating in the human bloodstream.
Junji Terao, Yuko Minami and Noriko Bando : Singlet molecular oxygen-quenching activity of carotenoids: relevance to protection of the skin from photoaging., Journal of Clinical Biochemistry and Nutrition, Vol.48, No.1, 57-62, 2010.
(Summary)
Carotenoids are known to be potent quenchers of singlet molecular oxygen [O(2) ((1)Δ(g))]. Solar light-induced photooxidative stress causes skin photoaging by accelerating the generation of reactive oxygen species via photodynamic actions in which O(2) ((1)Δ(g)) can be generated by energy transfer from excited sensitizers. Thus, dietary carotenoids seem to participate in the prevention of photooxidative stress by accumulating as antioxidants in the skin. An in vivo study using hairless mice clarified that a O(2) ((1)Δ(g)) oxygenation-specific peroxidation product of cholesterol, cholesterol 5α-hydroperoxide, accumulates in skin lipids due to ultraviolet-A exposure. Matrix metalloproteinase-9, a metalloproteinase family enzyme responsible for the formation of wrinkles and sagging, was enhanced in the skin of ultraviolet-A -irradiated hairless mice. The activation of metalloproteinase-9 and the accumulation of 5α-hydroperoxide, as well as formation of wrinkles and sagging, were lowered in mice fed a β-carotene diet. These results strongly suggest that dietary β-carotene prevents the expression of metalloproteinase-9 (at least in part), by inhibiting the photodynamic action involving the formation of 5α-hydroperoxide in the skin. Intake of β-Carotene therefore appears to be helpful in slowing down ultraviolet-A -induced photoaging in human skin by acting as a O(2) ((1)Δ(g)) quencher.
Aya Ouchi, Koichi Aizawa, Yuko Iwasaki, Takahiro Inakuma, Junji Terao, Shin-ichi Nagaoka and Kazuo Mukai : Kinetic study of the quenching reaction of singlet oxygen by carotenoids and food extracts in solution. Development of a singlet oxygen absorption capacity (SOAC) assay method., Journal of Agricultural and Food Chemistry, Vol.58, No.18, 9967-9978, 2010.
(Summary)
A kinetic study of the quenching reaction of singlet oxygen (1O2) with eight kinds of carotenoids and α-tocopherol was performed in ethanol/chloroform/D2O (50:50:1, v/v/v) solution at 35 °C. The overall rate constants, kQ (=kq+kr, physical quenching+chemical reaction), for the reaction of carotenoids with 1O2 were measured, using the competition reaction method, where endoperoxide was used as a singlet oxygen generator, 2,5-diphenyl-3,4-benzofuran (DPBF) as an UV-vis absorption prove, and α-tocopherol as a standard compound. The rate constants, kQ (S) and kQ (t1/2), were determined by analyzing the first-order rate constant (S) and the half-life (t1/2) of the decay curve of DPBF with carotenoids, respectively, showing good accordance with each other. Similar measurements were performed for tomato and carrot extracts. From the results, a new assay method that can quantify the singlet oxygen absorption capacity (SOAC) of antioxidants, including carotenoids, α-tocopherol, and vegetable extracts, has been proposed.
Rie Mukai, Reiko Nakao, Hironori Yamamoto, Takeshi Nikawa, Eiji Takeda and Junji Terao : Quercetin Prevents Unloading-Derived Disused Muscle Atrophy by Attenuating the Induction of Ubiquitin Ligases in Tail-Suspension Mice., Journal of Natural Products, Vol.73, No.10, 1708-1710, 2010.
(Summary)
The effects of quercetin (1) were investigated on disused muscle atrophy using mice that underwent tail suspension. Periodic injection of 1 into the gastrocnemius muscle suppressed muscle weight loss and ubiquitin ligase expression. Compound 1 reduced the enhancement of lipid peroxidation in the muscle. Injection of N-acetyl-l-cysteine, but not flavone (2), also prevented muscle weight loss and enhancement of lipid peroxidation. These findings demonstrate that 1 can prevent disused muscle atrophy by attenuating the expression of ubiquitin ligases and that such prevention originates from its antioxidant activity.
Kaeko Murota, Namiko Matsuda, Yasuaki Kashino, Yutaka Fujikura, Toshiyuki Nakamura, Yoji Kato, Ryosuke Shimizu, Syuji Okuyama, Hisashi Tanaka, Takatoshi Koda, Keiko Sekido and Junji Terao : alpha-Oligoglucosylation of a sugar moiety enhances the bioavailability of quercetin glucosides in humans., Archives of Biochemistry and Biophysics, Vol.501, No.1, 91-97, 2010.
(Summary)
Dietary intake of quercetin is suggested to be potentially beneficial for the prevention of various diseases. We examined the effect of alpha-oligoglucosylation of the sugar moiety of quercetin monoglucoside on its bioavailability in humans. Enzymatically modified isoquercitrin (EMIQ) was prepared by enzymatic deglycosylation and the subsequent of alpha-oligoglucosylation of quercetin 3-O-beta-rutinode (rutin). The plasma level of quercetin metabolites was instantly increased by oral intake of EMIQ and its absorption efficiency was significantly higher than that of isoquercitrin (quercetin 3-O-beta-glucoside; Q3G), and rutin. The profile of plasma quercetin metabolites after EMIQ consumption did not differ from that after Q3G consumption. The apparent log P of EMIQ indicated that EMIQ is more hydrophilic than Q3G but less than quercetin 3,4'-O-beta-diglucoside. These data indicated that enzymatic alpha-oligoglucosylation to the sugar moiety is effective for enhancing the bioavailability of quercetin glucosides in humans.
Noriko Bando, Naomi Muraki, Kaeko Murota, Junji Terao and Rintaro Yamanishi : Ingested quercetin but not rutin increases accumulation of hepatic beta-carotene in BALB/c mice., Molecular Nutrition & Food Research, Vol.54, No.Suppl 2, S261-S267, 2010.
(Summary)
Beta-carotene is a carotenoid with a range of reported health benefits besides vitamin A activity. If the enzymatic conversion of beta-carotene to retinal is suppressed in the digestive tract, residual beta-carotene that reaches the tissues increases. We evaluated the function of quercetin and rutin (quercetin-3-rutinoside) to increase the accumulation of beta-carotene in vitro and in vivo in BALB/c mice. When the conversion of beta-carotene by a preparation of the murine small intestine was measured in vitro, the addition of quercetin or rutin considerably inhibited the conversion. When the levels of hepatic beta-carotene and retinoids were measured among three groups of mice fed a diet supplemented with beta-carotene plus quercetin or rutin or beta-carotene alone (four to six mice per group), quercetin increased the level of beta-carotene and decreased the level of retinol, whereas rutin did not. These results demonstrate that quercetin can suppress the conversion of beta-carotene which develops in the cytosol of small intestinal epithelial cells, and that rutin whose rutinose-moiety prevents being absorbed in the small intestine cannot suppress the conversion in vivo. This study offers a novel insight into the interaction between flavonoids and carotenoids with respect to the health benefits from the latter.
(Keyword)
Animals / Intestinal Absorption / Intestine, Small / Liver / Male / Mice / Mice, Inbred BALB C / Quercetin / Retinoids / Rutin / Time Factors / vitamin A / beta Carotene / beta-Carotene 15,15'-Monooxygenase
Hiroaki Yanagawa, Junji Terao, Eiji Takeda, Yoshihisa Takaishi, Yoshiki Kashiwada, Kazuyoshi Kawazoe, Fushitani Shuji, Koichiro Tsuchiya, Aiko Yamauchi, Sato Chiho and Minoru Irahara : Consultation clinics for complementary and alternative medicine at Japanese university hospitals: An analysis at Tokushima University Hospital, Experimental and Therapeutic Medicine, Vol.1, No.3, 481-483, 2010.
(Summary)
Here, we report on a Consultation Clinic for Complementary and Alternative Medicine (CAM) which we established at Tokushima University Hospital in July of 2007 with the aim of providing person-to-person information on CAM, though not CAM therapy itself. In December of 2008, we received 55 applications for consultation, 37% concerning health foods, 37% Japanese herbal medicine (Kampo), and 26% various other topics. The consultants (nutritionists and pharmacists) communicated individually with 38 applicants; malignancies (26%) and cardiovascular disease (24%) were the main underlying concerns. To promote the quality of consultation, data was collected by means of focus group interviews concerning the perspective of the consultants. Safe and effective use of CAM requires a network of communication linking individuals, consultation teams, physicians, primary care institutions and university hospitals. To advance this goal, we plan to broaden the efforts described herein. Our findings indicate that the specific role of the consultation clinic in promoting the scientific use of CAM merits further study.
Masayuki Okuda, Noriko Bando, Junji Terao, Satoshi Sasaki, Shinichi Sugiyama, Ichiro Kunitsugu and Tatsuya Hobara : Association of serum carotenoids and tocopherols with atopic diseases in Japanese children and adolescents., Pediatric Allergy and Immunology, Vol.21, No.4 Pt 2, e705-e710, 2010.
(Summary)
The present study assessed whether serum carotenoids and tocopherols are associated with atopic diseases (eczema and asthma) in 10- and 13-yr-olds in a Japanese community. Of 2796 students attending schools in Shunan, Japan, in 2006, 396 students were randomly selected for this study using nested case-control design. Atopic diseases and dietary food intake were assessed using self-administered questionnaires, and serum antioxidants were analyzed using high-performance liquid chromatography. We found no associations between serum carotenoids and atopic diseases. However, odds ratios (OR)s for the third and fourth quartiles of serum alpha-tocopherol with atopic eczema were 0.33 (95% confidence interval: 0.15-0.73) and 0.36 (0.14-0.89), respectively, and the trend was negatively significant (P(trend) = 0.048). We did not find a significant association for asthma. In conclusion, serum alpha-tocopherol was negatively associated with the prevalence of eczema. Serum carotenoids did not show definitive protective effects in Japanese youth.
(Keyword)
Adolescent / Asthma / carotenoids / Case-Control Studies / children / Chromatography, High Pressure Liquid / Dermatitis, Atopic / Eating / Female / Humans / Japan / Male / Prevalence / Questionnaires / Tocopherols
Keiko Azuma, Katsunari Ippoushi and Junji Terao : Evaluation of tolerable levels of dietary quercetin for exerting its antioxidative effect in high cholesterol-fed rats., Food and Chemical Toxicology, Vol.48, No.4, 1117-1122, 2010.
(Summary)
The tolerable level of dietary quercetin for exerting its antioxidative effect was evaluated in high cholesterol-fed rats, using quercetin-containing diets (31-1260 mg quercetin/kg body weight/day) and onion diets (19-94 mg quercetin aglycone equivalent/kg body weight/day), from the viewpoint of a safety assessment. After feeding for 4 weeks, the urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) levels of the quercetin-containing diet groups fed more than 157 mg quercetin/kg body weight/day were higher than the group fed a quercetin-free diet, although the plasma quercetin metabolite levels and plasma antioxidative activity were elevated depending on the amounts of quercetin or onion diet intake. No significant effect on body weight gain by quercetin-containing diets or onion diets was observed. However, ratios of the liver and kidney weights to the body weight were significantly increased in the quercetin-containing diet groups fed more than 314 mg and 157 mg quercetin/kg body weight/day, respectively, and in the onion diet groups fed more than 47 mg quercetin aglycone equivalent/kg body weight/day. These results indicated that the tolerable level for dietary quercetin for exerting its antioxidative effect was between 126 and 157 mg/kg/day for the quercetin diet and between 19 and 34 mg/kg/day for the onion diet.
Akiyuki Yokoyama, Hiroyuki Sakakibara, Alan Crozier, Yoshichika Kawai, Asako Matsui, Junji Terao, Shigenori Kumazawa and Kayoko Shimoi : Quercetin metabolites and protection against peroxynitrite-induced oxidative hepatic injury in rats., Free Radical Research, Vol.43, No.10, 913-921, 2009.
(Summary)
Quercetin has strong antioxidant potency. Quercetin-3'-O-sulphate (Q3'S) and quercetin-3-O-glucuronide (Q3GA) are the main circulating metabolites after consumption of quercetin-O-glucoside-rich diets by humans. However, information about how these quercetin metabolites function in vivo is limited. Hence, this study evaluated the efficacy of Q3'S and Q3GA for the protection of oxidative injury using in vitro and in vivo experiments. Peroxynitrite-mediated hepatic injury in rats was induced by administration of galactosamine/lipopolysaccharide (GalN/LPS). Twenty-four hours after GalN/LPS treatment, plasma ALT and AST levels delta increased significantly. However, pretreatment with 4(G)-alpha-D-glucopyranosyl rutin, a quercetin glycoside (30 mg/kg body weight), prevented these increases and reduced nitrotyrosine formation, indicating that consumption of quercetin glycosides prevent oxidative hepatotoxicity. Moreover, physiological levels of Q3'S and Q3GA (1 microM) effectively prevented peroxynitrite-induced nitrotyrosine formation in human serum albumin in in vitro experiments. These findings indicate peroxynitrite-induced oxidative hepatotoxicity is protected by the in vivo metabolites of quercetin, Q3'S and Q3GA.
Masayuki Okuda, Satoshi Sasaki, Noriko Bando, Michio Hashimoto, Ichiro Kunitsugu, Shinichi Sugiyama, Junji Terao and Tatsuya Hobara : Carotenoid, tocopherol, and fatty acid biomarkers and dietary intake estimated by using a brief self-administered diet history questionnaire for older Japanese children and adolescents., Journal of Nutritional Science and Vitaminology, Vol.55, No.3, 231-241, 2009.
(Summary)
We investigated the association between nutrient biomarkers and dietary intake estimated using a brief self-administered dietary history questionnaire (BDHQ) for Japanese children and adolescents. Blood samples were collected from 398 subjects (5th graders of elementary school aged 10-11 y, and 2nd graders of secondary schools aged 13-14 y) randomly selected from among students in Shunan City, Japan, who were then required to answer two questionnaires. Spearman correlations were calculated between dietary intake and the corresponding biomarkers (serum carotenoids, tocopherols, and erythrocyte fatty acids). Correlations with beta-carotene and beta-cryptoxanthin were significant in the 13- and 14-y age group (r=0.220-0.333, p<0.030) and the 10- and 11-y age subgroup who answered the questionnaire with assistance (r=0.295-0.299, respectively, p=0.006). Consumption of green-yellow vegetables and fruits was significantly correlated with beta-carotene and beta-cryptoxanthin levels (r=0.205-0.341, p<0.047). In the 13- and 14-y age group, correlations with eicosapentaenoic and docosahexaenoic acids were between 0.215 and 0.473 (p<0.040). Total seafood intake was significantly correlated with marine n-3 polyunsaturated fatty acids (PUFAs; r=0.239-0.420, p<0.023). In the 10- and 11-y age subgroup who completed the questionnaire with assistance, seafood intake was significantly correlated with marine n-3 PUFAs (r=0.239-0.243, p<0.032). In conclusion, dietary intake assessed using the BDHQ reflects the corresponding biomarkers for 13- and 14-y-olds; however, when used for elementary school children, caution is necessary in interpreting the results.
(Keyword)
Adolescent / Biological Markers / Body Constitution / carotenoids / children / Diet / Diet Records / Erythrocytes / Fatty Acids / Female / Fruit / Humans / Japan / Male / Parents / Questionnaires / Tocopherols / Vegetables / Xanthophylls / beta Carotene
Kyuichi Kawabata, Yoshichika Kawai and Junji Terao : Suppressive effect of quercetin on acute stress-induced hypothalamic-pituitary-adrenal axis response in Wistar rats., The Journal of Nutritional Biochemistry, Vol.21, No.5, 374-380, 2009.
(Summary)
The flavonoid quercetin is considered to have beneficial effects on human health. We recently have shown that quercetin-enriched foods reduced the duration of immobility time in a rat forced swimming test, indicating that dietary quercetin is promising as an antidepressant-like factor, whereas its mechanism of action is poorly understood. The aim of this study is to investigate the effects of quercetin on water immersion-restraint (WIR), stress-induced hypothalamic-pituitary-adrenal (HPA) axis activation, which is a major component of stress response and plays an important role in the pathology of depression. Quercetin administration to rats significantly suppressed WIR stress-induced increase of plasma corticosterone and adrenocorticotropic hormone levels as well as the mRNA expression of corticotropin-releasing factor (CRF) in the hypothalamic region. In addition, quercetin modulated the DNA binding activities of glucocorticoid receptor and phosphorylated cyclic adenosine 3',5'-monophosphate (cAMP) response element binding protein as well as the phosphorylation of extracellular signal-regulated kinase 1/2 in the hypothalamic region, all of which are known to regulate the expression of CRF mRNA. Taken together, these results suggest that dietary quercetin attenuates the HPA axis activation by the suppression of the CRF mRNA expression.
Yoshichika Kawai, Satomi Saito, Tomomi Nishikawa, Akari Ishisaka, Kaeko Murota and Junji Terao : Different profiles of quercetin metabolites in rat plasma: comparison of two administration methods., Bioscience, Biotechnology, and Biochemistry, Vol.73, No.3, 517-523, 2009.
(Summary)
The bioavailability of polyphenols in human and rodents has been discussed regarding their biological activity. We found different metabolite profiles of quercetin in rat plasma between two administration procedures. A single intragastric administration (50 mg/kg) resulted in the appearance of a variety of metabolites in the plasma, whereas only a major fraction was detected by free access (1% quercetin). The methylated/non-methylated metabolites ratio was much higher in the free access group. Mass spectrometric analyses showed that the fraction from free access contained highly conjugated quercetin metabolites such as sulfo-glucuronides of quercetin and methylquercetin. The metabolite profile of human plasma after an intake of onion was similar to that with intragastric administration in rats. In vitro oxidation of human low-density lipoprotein showed that methylation of the catechol moiety of quercetin significantly attenuated the antioxidative activity. These results might provide information about the bioavailability of quercetin when conducting animal experiments.
(Keyword)
Animals / Antioxidants / Chromatography, High Pressure Liquid / Humans / Male / mass spectrometry / Quercetin / Rats / Structure-Activity Relationship
Ibrahim Dalia Ismaeil Hemdan, Katsuya Hirasaka, Reiko Nakao, Shohei Kohno, Sachiko Kagawa, Tomoki Abe, Akiko Harada, Yuushi Okumura, Yutaka Nakaya, Junji Terao and Takeshi Nikawa : Polyphenols prevent clinorotation-induced expression of atrogenes in mouse C2C12 skeletal myotubes., The Journal of Medical Investigation : JMI, Vol.56, No.1-2, 26-32, 2009.
(Summary)
Oxidative stress is a key factor in stimulating the expression of atrogenes, which are muscle atrophy-related ubiquitin ligases, in skeletal muscle, and it induces muscle atrophy during unloading. However, the effects of antioxidative nutrients on atrogene expression have not been demonstrated. We report on the inhibitory effects of polyphenols, such as epicatechin (EC), epicatechin gallate (ECg) and epigallocatechin gallate (EGCg) and quercetin, on atrogene expression up-regulated by three dimensional (3D)-clinorotation or glucocorticoid. These treatments markedly elevated the expression of atrogenes, including atrogin-1 and MuRF-1, in mouse C2C12 myoblasts and myotubes. Interestingly, EC, ECg, EGCg and quercetin significantly decreased the expression of atrogin-1 and MuRF-1 up-regulated by 3D-clinorotation, whereas they hardly affected atrogene expression induced by dexamethasone. ERK signaling is a well known MAPK pathway to mediate oxidative stress. Therefore, we also investigated the effect of these polyphenols on phosphorylation of ERK in C2C12 myotubes. As expected, EC, ECg, EGCg, and quercetin significantly suppressed phosphorylation of ERK, corresponding to the up-regulation of atrogenes induced by 3D-clinorotation. These results suggest that antioxidative nutrients, such as catechins and quercetin, suppress atrogene expression in skeletal muscle cells, possibly through the inhibition of ERK signaling. Thus, catechins and quercetin may prevent unloading-mediated muscle atrophy.
Yoshichika Kawai, Hiroko Tanaka, Kaeko Murota, Michitaka Naito and Junji Terao : (-)-Epicatechin gallate accumulates in foamy macrophages in human atherosclerotic aorta: implication in the anti-atherosclerotic actions of tea catechins., Biochemical and Biophysical Research Communications, Vol.374, No.3, 527-532, 2008.
(Summary)
The localization and target sites of tea catechins underlying their biological activity including anti-atherosclerotic activity have not yet been fully understood. To identify the target sites of catechins in vivo, we have developed a novel monoclonal antibody (mAb5A3) specific for (-)-epicatechin-3-gallate (ECg), one of the major tea catechins. The immunoreactive materials with mAb5A3 were detected in the human atherosclerotic lesions but not in the normal aorta, and were specifically localized in the macrophage-derived foam cells. In vitro experiments using macrophage-like cell lines also showed the significant accumulation of ECg in the cells. We also demonstrated that ECg could suppress the gene expression of a scavenger receptor CD36, a key molecule for foam cell formation, in macrophage cells. These results, for the first time, showed the target site of a tea component ECg in the aorta and might provide a mechanism for the anti-atherosclerotic actions of the catechins.
Yuko Minami, Kyuichi Kawabata, Yoshiaki Kubo, Seiji Arase, Katsuya Hirasaka, Takeshi Nikawa, Noriko Bando, Yoshichika Kawai and Junji Terao : Peroxidized cholesterol-induced matrix metalloproteinase-9 activation and its suppression by dietary beta-carotene in photoaging of hairless mouse skin., The Journal of Nutritional Biochemistry, Vol.20, No.5, 389-398, 2008.
(Summary)
The activation of matrix metalloproteinase (MMP)-9 leading to the formation of wrinkle and sagging of skin is an essential step in the skin photoaging on exposure to ultraviolet A (UVA). This study attempted to elucidate the role of peroxidized cholesterol including cholesterol hydroperoxides (Chol-OOHs), primary products of lipid peroxidation in biomembranes, in MMP-9 activation and the effect of dietary beta-carotene in MMP-9 activation. Hairless mice were subjected to periodic UVA irradiation for 8 weeks. The amount of peroxidized cholesterol detected as total hydroxycholesterol in the skin was increased significantly by the exposure. The activity and protein level of MMP-9 were elevated with wrinkling and sagging formation. MMP-9 activity was also enhanced by the intracutaneous injection of Chol-OOHs into the mouse skin. Adding beta-carotene to the diet of the mice during the period of irradiation suppressed the activity and expression of MMP-9 as well as the wrinkling and sagging formation. The amount of cholesterol 5alpha-hydroperoxide, a singlet molecular oxygen oxygenation-specific peroxidized cholesterol, was significantly lowered by the addition of beta-carotene to the diet. These results strongly suggest that Chol-OOHs formed on exposure to UVA contribute to the expression of MMP-9, resulting in photoaging. Dietary beta-carotene prevents the expression of MMP-9, at least partly, by inhibiting photodynamic action involved in the formation of Chol-OOHs.
Yuko Shiba, Takashi Kinoshita, Hiroshi Chuman, Yutaka Taketani, Eiji Takeda, Yoji Kato, Michitaka Naito, Kyuichi Kawabata, Akari Ishisaka, Junji Terao and Yoshichika Kawai : Flavonoids as Substrates and Inhibitors of Myeloperoxidase : Molecular Actions of Aglycone and Metabolites, Chemical Research in Toxicology, Vol.21, No.8, 1600-1609, 2008.
(Summary)
Myeloperoxidase (MPO), secreted by activated neutrophils and macrophages at the site of inflammation, may be implicated in the oxidation of protein/lipoprotein during the development of cardiovascular diseases. Flavonoids have been suggested to act as antioxidative and anti-inflammatory agents in vivo; however, their molecular actions have not yet been fully understood. In this study, we examined the molecular basis of the inhibitory effects of dietary flavonoids, such as quercetin, and their metabolites on the catalytic reaction of MPO using a combination of biological assays and theoretical calculation studies. Immunohistochemical staining showed that a quercetin metabolite was colocalized with macrophages, MPO, and dityrosine, an MPO-derived oxidation product of tyrosine, in human atherosclerotic aorta. Quercetin and the plasma metabolites inhibited the formation of dityrosine catalyzed by the MPO enzyme and HL-60 cells in a dose-dependent manner. Spectrometric analysis indicated that quercetin might act as a cosubstrate of MPO resulting in the formation of the oxidized quercetin. Quantitative structure-activity relationship studies showed that the inhibitory actions of flavonoids strongly depended not only on radical scavenging activity but also on hydrophobicity (log P). The requirement of a set of hydroxyl groups at the 3, 5, and 4'-positions and C2-C3 double bond was suggested for the inhibitory effect. The binding of quercetin and the metabolites to a hydrophobic region at the entrance to the distal heme pocket of MPO was also proposed by a computer docking simulation. The current study provides the structure-activity relationships for flavonoids as the anti-inflammatory dietary constituents targeting the MPO-derived oxidative reactions in vivo.
Hiroyuki Sakakibara, Saki Yoshino, Toshitsugu Miyazaki, Yoshichika Kawai and Junji Terao : Antidepressant-like Effect of Ginseng (Panax ginseng C.A. Meyer) in Behavioral Models, Journal of Clinical Biochemistry and Nutrition, Vol.43, No.Suppl.1, 255-258, 2008.
62.
Akira Murakami, Hitoshi Ashida and Junji Terao : Multitargeted cancer prevention by quercetin., Cancer Letters, Vol.269, No.2, 315-325, 2008.
(Summary)
Quercetin is an anti-oxidative flavonoid widely distributed in the plant kingdom. Phenolic hydroxyl groups at the B-ring and the 3-position are responsible for its free radical-scavenging activity. Quercetin is commonly present as a glycoside and is converted to glucuronide/sulfate conjugates during intestinal absorption and only conjugated metabolites are therefore found in circulating blood. Although metabolic conversion attenuates its biological effects, active aglycone may be generated from the glucuronide conjugates by enhanced beta-glucuronidase activity during inflammation. With respect to its relationship with molecular targets relevant to cancer prevention, quercetin aglycone has been shown to interact with some receptors, particularly an aryl hydrocarbon receptor, which is involved in the development of cancers induced by certain chemicals. Quercetin aglycone has also been shown to modulate several signal transduction pathways involving MEK/ERK and Nrf2/keap1, which are associated with the processes of inflammation and carcinogenesis. Rodent studies have demonstrated that dietary administration of this flavonol prevents chemically induced carcinogenesis, especially in the colon, whilst epidemiological studies have indicated that an intake of quercetin may be associated with the prevention of lung cancer. Dietary quercetin is, therefore, a promising agent for cancer prevention and further research is warranted.
Kazuma Yoshizumi, Kaeko Murota, Shiro Watanabe, Hironori Tomi, Tomoko Tsuji and Junji Terao : Chiisanoside is not absorbed but inhibits oil absorption in the small intestine of rodents., Bioscience, Biotechnology, and Biochemistry, Vol.72, No.4, 1126-1129, 2008.
(Summary)
Chiisanoside is the main component of Acanthopanax sessiliflorus leaves. Simultaneous administration of chiisanoside resulted in a decrease in the plasma TG level and increase of undigested TG in the intestinal lumen after oil gavage to mice. This suggests that chiisanoside has the potential to prevent obesity as a lipase inhibitor which suppresses fat absorption in vivo.
Yuko Minami, Kanako Yokoyama, Noriko Bando, Yoshichika Kawai and Junji Terao : Occurrence of singlet oxygen oxygenation of oleic acid and linoleic acid in the skin of live mice., Free Radical Research, Vol.42, No.3, 197-204, 2008.
(Summary)
To assess the contribution of singlet molecular oxygen [O(2) ((1)Delta(g))] to lipid peroxidation in vivo, this study combined gas chromatography-mass spectrometry with thin layer chromatography to analyse peroxidized lipids in the skin of hairless mice. Hydroxyoctadecenoate isomers and unconjugated hydroxyoctadecadienoate isomers derived from peroxidized oleic acid and linoleic acid, respectively, which are specific to O(2) ((1)Delta(g))-dependent oxygenation, were detected in the skin of live mice under ordinary feeding conditions. Short-term ultraviolet A (UVA)-irradiation of the skin in vivo elevated levels of the unconjugated hydroxyoctadecadienoate isomers significantly, whereas the irradiation of skin homogenate in vitro increased levels of all isomers derived from both O(2) ((1)Delta(g)) and free radical-dependent oxygenation to a much greater extent. This is the first report to demonstrate the occurrence of O(2) ((1)Delta(g))-specific oxygenation of unsaturated fatty acids in living animals.
(Keyword)
Animals / Chromatography, Gas / Chromatography, Thin Layer / Free Radicals / Linoleic Acid / lipid peroxidation / Male / mass spectrometry / Mice / Mice, Hairless / Oleic Acid / Oxygen / Singlet Oxygen / Skin / Ultraviolet Rays
Yoshichika Kawai, Akari Ishisaka, Satomi Saito, Koji Uchida, Noriyuki Shibata, Makio Kobayashi, Yoshiko Fukuchi, Michitaka Naito and Junji Terao : Immunochemical detection of flavonoid glycosides: development, specificity, and application of novel monoclonal antibodies., Archives of Biochemistry and Biophysics, Vol.476, No.2, 124-132, 2008.
(Summary)
Flavonoid-rich diets are expected to decrease the risk of cardiovascular diseases. The localization and target sites of flavonoids underlying the protective mechanism in vivo have not been fully investigated because the methods for detection of flavonoids have been limited to chemical analysis such as high-performance liquid chromatography. To further understand the actions of flavonoids in vivo, we developed a novel methodology that immunochemically evaluates flavonoids using specific antibodies. Quercetin-3-glucuronide (Q3GA), a major metabolite in human plasma, was coupled with keyhole limpet hemocyanin. Alternatively, the sugar moiety of quercetin-3-glucoside (Q3G) was succinylated and then coupled with a carrier protein. Using these two immunogens, we finally obtained two monoclonal antibodies, mAb14A2 and mAb11G6, from the immunogen using Q3GA and Q3G, respectively. Competitive enzyme-linked immunosorbent assay showed the unique difference in the specificity between the two similar antibodies: mAb14A2 recognized several quercetin-3-glycosides including Q3G and rutin but mAb11G6 was highly specific to the Q3G structure. The macrophage-derived foam cells in human atherosclerotic lesions were significantly stained with mAb14A2 but scarcely with mAb11G6. These results showed that the anti-flavonoid glycoside antibodies are useful tools for evaluating their localization in tissues and that the specificities strongly depend on the immunogen design for synthesizing the hapten-protein conjugates.
Yoshichika Kawai, Tomomi Nishikawa, Yuko Shiba, Satomi Saito, Kaeko Murota, Noriyuki Shibata, Makio Kobayashi, Masaya Kanayama, Koji Uchida and Junji Terao : Macrophage as a target of quercetin glucuronides in human atherosclerotic arteries: implication in the anti-atherosclerotic mechanism of dietary flavonoids., The Journal of Biological Chemistry, Vol.283, No.14, 9424-9434, 2008.
(Summary)
Epidemiological studies suggest that the consumption of flavonoid-rich diets decreases the risk of cardiovascular diseases. However, the target sites of flavonoids underlying the protective mechanism in vivo are not known. Quercetin represents antioxidative/anti-inflammatory flavonoids widely distributed in the human diet. In this study, we raised a novel monoclonal antibody 14A2 targeting the quercetin-3-glucuronide (Q3GA), a major antioxidative quercetin metabolite in human plasma, and found that the activated macrophage might be a potential target of dietary flavonoids in the aorta. Immunohistochemical studies with monoclonal antibody 14A2 demonstrated that the positive staining specifically accumulates in human atherosclerotic lesions, but not in the normal aorta, and that the intense staining was primarily associated with the macrophage-derived foam cells. In vitro experiments with murine macrophage cell lines showed that the Q3GA was significantly taken up and deconjugated into the much more active aglycone, a part of which was further converted to the methylated form, in the activated macrophages. In addition, the mRNA expression of the class A scavenger receptor and CD36, which play an important role for the formation of foam cells, was suppressed by the treatment of Q3GA. These results suggest that injured/inflamed arteries with activated macrophages are the potential targets of the metabolites of dietary quercetin. Our data provide a new insight into the bioavailability of dietary flavonoids and the mechanism for the prevention of cardiovascular diseases.
Hiroyuki Sakakibara, Saki Yoshino, Yoshichika Kawai and Junji Terao : Antidepressant-like effect of onion (Allium cepa L.) powder in a rat behavioral model of depression., Bioscience, Biotechnology, and Biochemistry, Vol.72, No.1, 94-100, 2008.
(Summary)
The present study evaluated the antidepressant-like effect of the quercetin-rich vegetable, onion, by using the rat behavioral model of depression, the forced swimming test (FST). Daily administration of onion powder at a dosage of 50 mg/kg of body weight/day for 14 days significantly reduced the immobility time in FST without changing the motor dysfunction, indicating that the daily consumption of onion exerted antidepressant-like activity. The plasma corticosterone level was elevated after an FST trial, and pretreatment with onion powder did not modulate this elevation. Although the FST trial tended to increase the dopaminergic activity in the rat hypothalamus, the administration of onion powder (50 mg/kg) suppressed the increase in the turnover of this neurotransmitter. However, the same prevention was also observed with a higher dosage of onion, in which no significant antidepressant effect was apparent. The results of the present study suggest that onion exerted antidepressant-like activity in a behavioral model that acted independently of the hypothalamic-pituitary-adrenal axis.
Junji Terao, Yoshichika Kawai and Kaeko Murota : Vegetable flavonoids and cardiovascular disease., Asia Pacific Journal of Clinical Nutrition, Vol.17, No.Suppl 1, 291-293, 2008.
(Summary)
Studies have suggested that dietary flavonoids are helpful in the prevention of atherosclerosis and cardiovascular disease. Antioxidant activity should be noted as underlying mechanism of their health impact in the vascular system, as atherosclerosis is closely related to oxidative events such as oxidized LDL accumulation in the macrophages. Vegetables contain a variety of flavonoids, such as flavonols, flavones and anthocyanidins. We focused on quercetin (3,3',4',5,7- pentahydroxyflavone), a major flavonoid in onion, and its anti-atherosclerotic effect was examined from the aspect of the bioavailability and translocation to the target site. Although quercetin exists as its glucoside form in onion, it is metabolized into several glucuronides and/or sulfate conjugates with or without methylation during its intestinal absorption. We found that these metabolites circulating in the human blood stream were mostly localized in plasma albumin fraction, but not LDL fraction. Onion consumption failed to enhance the antioxidant activity of plasma fraction against LDL oxidation, indicating that the level of quercetin metabolites bound to albumin is insufficient to exert the antioxidative effect in vivo. In contrast, we discovered that quercetin metabolites accumulate in the aorta tissue and exerted their antioxidant activity, when rabbits were fed with quercetin glucoside and high cholesterol diet. Furthermore, quercetin metabolites were detected in human atherosclerotic aorta exclusively. These imply that quercetin metabolites are incorporated into the atherosclerotic region and act as complementary antioxidants, when oxidative stress is loaded in the vascular system. It is likely that plasma albumin is a carrier for translocation of quercetin metabolites to vascular target.
Noriko Bando, Wakamatsu Saoyi and Junji Terao : Effect of excessive intake of quercetin on the vitamin E level and antioxidative enzyme activities of mouse liver under paraquat-induced oxidative stress, Bioscience, Biotechnology, and Biochemistry, Vol.71, No.10, 2569-2572, 2007.
(Summary)
The liver alpha-tocopherol level of the paraquat fed mice group was lower than that of the control diet-fed group. An excessive intake of quercetin lowered the liver alpha-tocopherol level of the control diet-fed mice group, but did not affect it in the paraquat-fed mice group. The same quercetin intake significantly increased the superoxide dismutase and glutathione peroxidase activities in the liver of both groups, indicating that excessive quercetin intake can either promote or attenuate oxidative stress in the liver.
Minami Yuko, Yokoi sayuri, Setoyama Mari, Noriko Bando, Takeda Sayaka, Yoshichika Kawai and Junji Terao : Combination of TLC blotting and gas chromatography-mass spectrometry for analysis of peroxidized cholesterol, Lipids, Vol.42, No.11, 1055-1063, 2007.
(Summary)
We have established a sensitive and convenient method for analysis of cholesterol hydroperoxides (Chol-OOHs) as trimethylsilyloxyl derivatives using diphenylpyrenylphosphine (DPPP)-thin-layer chromatography (TLC) blotting and gas chromatography-electron ionization-mass spectrometry/selected-ion monitoring (GC-EI-MS/SIM). Chol-OOH standards were prepared by photosensitized oxidation and azo radical-induced peroxidation of cholesterol. Trimethylsilyloxyl derivatives of cholesterol 5alpha-hydroperoxide (Chol 5alpha-OOH), cholesterol 7alpha-hydroperoxide (Chol 7alpha-OOH), and cholesterol 7beta-hydroperoxide (Chol 7beta-OOH) could be separated from one another in the SIM chromatogram using a fragment ion with elimination of trimethylsilanol from the molecular ion. This method was used to characterize peroxidized cholesterol from azo radical-exposed human low-density lipoprotein and UVA-irradiated human keratinocytes in the presence of hematoporphyrin. Finally, we succeeded in the quantification of each Chol-OOH isomer present in hairless mouse skin with and without UVA irradiation by use of beta-sitosterol hydroperoxide as internal standard. The accumulation of Chol 5alpha-OOH with Chol 7alpha/betaOOH in the skin indicates that singlet molecular oxygen ((1)O(2)) participated in the peroxidation of skin cholesterol, because Chol 5alpha-OOH is known to be a (1)O(2) specific cholesterol peroxidation product. We concluded that the combination of DPPP-TLC blotting and GC-EI-MS/SIM is useful for quantifying peroxidized cholesterol in biological samples and confirming the participation of (1)O(2) in oxidative stress.
Kaeko Murota, Azusa Hotta, Hikaru Ido, Yoshichika Kawai, Jae-Hak Moon, Keiko Sekido, Hiroki Hayashi, Takahiro Inakuma and Junji Terao : Antioxidant capacity of albumin-bound quercetin metabolites after onion consumption in humans., The Journal of Medical Investigation : JMI, Vol.54, No.3-4, 370-374, 2007.
(Summary)
Quercetin is a major dietary flavonoid found in onions and other vegetables. It is known that dietary quercetin is metabolized in the intestinal mucosa and the liver and is present as its glucuronide/sulfate conjugates with or without methylation. Although quercetin is known to possess strong antioxidant activity, there are only limited reports on the antioxidant activity of its metabolites. In this study, the antioxidant capacity of quercetin metabolites under physiological conditions was investigated. After consumption of cooked onion, more than 80% of quercetin metabolites were localized in the human plasma fraction containing concentrated serum albumin. Other lipoprotein fractions contained only small amounts of quercetin metabolites. Addition of quercetin 3-O-beta-glucuronide to the lipoprotein-eliminated plasma fraction generated antioxidant activity against LDL oxidation in a dose-dependent manner. However, onion consumption failed to enhance the antioxidant activity of the lipoprotein-eliminated plasma fraction against LDL oxidation, probably because the amount of quercetin metabolites bound to albumin was less than the effective level in an ex vivo study. The physiological role of plasma albumin in retaining quercetin metabolites needs to be further clarified.
Azuma Keiko, Minami Yuko, Ippoushi Katsunari and Junji Terao : Lowering effect of onion Intake on oxidative stress biomarkers in streptozotocin-induced diabetic rats, Journal of Clinical Biochemistry and Nutrition, Vol.40, No.2, 131-140, 2007.
(Summary)
The protective effect of onion against oxidative stress in streptozotosin-induced diabetic rats was investigated in comparison with that of quercetin aglycone. We measured oxidative stress biomarkers involving the susceptibility of the plasma against copper ion-induced lipid peroxidation, which was estimated by the amounts of thiobarbituric acid-reactive substances (TBARS) and cholesteryl ester hydroperoxides, and urine TBARS and 8-hydroxydeoxyguanosine contents. After the 12-week feeding period, plasma glucose levels and these biomarkers increased in diabetic rats compared to normal rats. In diabetic rats fed a 6.0% onion diet (quercetin equivalent: 0.023%), quercetin metabolites accumulated in the plasma at concentrations of approximately 35 microM. Onion intake decreased plasma glucose levels and lowered the oxidative stress biomarkers. On the other hand, quercetin metabolites in the plasma of rats fed a diet with 0.023% quercetin aglycone were found at lower concentrations (14.2 microM) than the rats fed the onion diet. Furthermore, oxidative stress biomarkers were higher in the quercetin diet group compared to the onion diet group. These results strongly suggest that onion intake suppresses diabetes-induced oxidative stress more effectively than the intake of the same amount of quercetin aglycone alone.
Dong-Soon Kim, Hideki Takai, Masato Arai, Shouta Araki, Masaru Mezawa, Yoshichika Kawai, Kaeko Murota, Junji Terao and Yorimasa Ogata : Effects of Quercetin and Quercetin 3-Glucuronide on the Expression of Bone Sialoprotein Gene, Journal of Cellular Biochemistry, Vol.101, No.3, 790-800, 2007.
(Summary)
Quercetin is a typical flavonol-type flavonoid and is present in a variety of vegetables, and their antioxidant effect implies their possible role in the prevention of oxidative stress related chronic diseases. Bone sialoprotein (BSP) is a noncollagenous protein of the extracellular matrix in the mineralized connective tissues that has been implicated in the nucleation of hydroxyapatite crystals. Previously, we reported that isoflavone (genistein) activated BSP gene transcription is mediated through an inverted CCAAT box in the proximal BSP gene promoter. The present study investigates the regulation of BSP transcription in a rat osteoblast-like cell line, ROS 17/2.8 cells, by quercetin and its conjugated metabolite quercetin 3-glucuronide. Quercetin and quercetin 3-glucuronide (5 microM) increased the BSP mRNA levels at 12 h and quercetin upregulated the Cbfa1/Runx2 mRNA expression at 12 h. From transient transfection assays using various sized BSP promoter-luciferase constructs, quercetin increased the luciferase activity of the construct (pLUC3), including the promoter sequence nucleotides -116 to -43. Transcriptional stimulations by quercetin were almost completely abrogated in the constructs that included 2 bp mutations in the inverted CCAAT and FRE elements whereas the CCAAT-protein complex did not change after stimulation by quercetin according to gel shift assays. Quercetin increased the nuclear protein binding to the FRE and 3'-FRE. These data suggest that quercetin and quercetin 3-glucuronide increased the BSP mRNA expression, and that the inverted CCAAT and FRE elements in the promoter of the BSP gene are required for quercetin induced BSP transcription.
Yoshichika Kawai, Sayaka Takeda and Junji Terao : Lipidomic analysis for lipid peroxidation-derived aldehydes using gas chromatography-mass spectrometry, Chemical Research in Toxicology, Vol.20, No.1, 99-107, 2007.
(Summary)
A lipidomic method is described for the measurement of lipid peroxidation-derived aldehydes using gas chromatography/electron ionization/mass spectrometry with selected ion monitoring (GC/EI/MS-SIM). Aldehydes in the samples were converted into their pentafluorobenzyl (PFB)-oximes using PFB-hydroxylamine, and other functional groups such as the hydroxyl groups were further derivatized into the trimethylsilyl ethers. The PFB-oxime derivatives could be comprehensively detected by the SIM of m/z 181, which is a characteristic fragment ion of the PFB-oxime derivatives. At the same time, each aldehyde was classified into five groups (alkanals, 2-alkenals, 2,4-alkadienals, 2-hydroxyalkanals, and 4-hydroxy-2-alkenals) by SIM of the structure-specific fragment ions. Determination of the 4-hydroxy-2-alkenals was also performed by confirmation of their higher reactivity with the sulfhydryl group. On the basis of the mass spectrometric characterization, we have identified at least 33 aldehydes formed upon the FeII-mediated decomposition of the arachidonic acid-, linoleic acid-, and docosahexaenoic acid-hydroperoxides in vitro. We then applied this system to the in vivo samples and successfully observed the increase in aldehydes in the liver of mice intraperitoneally injected with bromobenzene, an experimental animal model for lipid peroxidation. Using this comprehensive analysis, unique differences in the formation between each aldehyde could be observed. This method is useful for simultaneously monitoring the lipid peroxidation-derived aldehydes formed under oxidative stress in vivo.
Yoshichika Kawai, Mariko Miyoshi, Jae-Hak Moon and Junji Terao : Detection of cholesteryl ester hydroperoxide isomers using gas chromatography-mass spectrometry combined with thin-layer chromatography blotting., Analytical Biochemistry: Methods in the Biological Sciences, Vol.360, No.1, 130-137, 2007.
(Summary)
Oxidative modification of low-density lipoprotein (LDL) has been implicated in the pathogenesis of atherosclerosis. During the oxidation of LDL, cholesteryl esters, the major lipid components in LDL, are oxidized to cholesteryl ester hydroperoxides (CEOOH). The isomers of CEOOH may reflect the reactive species that initiate the peroxidation reaction. In the current study, a novel analytical method for the determination of CEOOH isomers, especially cholesteryl linoleate hydroperoxide isomers, was developed using the combination of two chromatographic techniques: (i) thin-layer chromatography blotting with diphenyl-1-pyrenylphosphine (DPPP) fluorescent detection (DPPP-TLC blotting) and (ii) gas chromatography-electron ionization-mass spectrometry (GC-EI-MS). CEOOH was applied to DPPP-TLC blotting, the obtained DPPP-derived fluorescent spots containing cholesteryl ester hydroxides were extracted and derivatized (hydrogenation, transmethylation, and trimethylsilylation), and the formed methyl ester/trimethylsilylether derivatives of hydroxyoctadecenoic acid were then analyzed by GC-EI-MS. The CEOOH isomers were determined by selected ion monitoring of isomer-specific fragment ions originated from the alpha-cleavage of the trimethylsilyloxyl group. Using these two chromatographic techniques, we were able to detect isomeric CEOOH in the oxidized human LDL. Our results indicated that GC-EI-MS analysis combined with DPPP-TLC blot is a specific method for analyzing cholesteryl ester hydroperoxide isomers in biological samples such as oxidized LDL.
Koizumi Tomoko, Noriko Bando, Junji Terao and Rintaro Yamanishi : Feeding with Both β-Carotene and Supplemental α-Tocopherol Enhances Type 1 Helper T Cell Activity among Splenocytes Isolated from DO11.10 Mice, Bioscience, Biotechnology, and Biochemistry, Vol.70, No.12, 3042-3045, 2006.
(Summary)
beta-Carotene and/or supplemental alpha-tocopherol were fed to DO11.10 mice to investigate their effect on the immune function of naive splenocytes. A high secretion of interleukin-12 and interferon-gamma in response to the ex vivo primary antigen presentation occurred only when both were fed. This is consistent with the suppressed immunoglobulin E production under the similar condition described in our previous report.
Yoshichika Kawai, Hitomi Kiyokawa, Yuki Kimura, Yoji Kato, Koichiro Tsuchiya and Junji Terao : Hypochlorous acid-derived modification of phospholipids: characterization of aminophospholipids as regulatory molecules for lipid peroxidation., Biochemistry, Vol.45, No.47, 14201-14211, 2006.
(Summary)
Hypochlorous acid (HOCl), an inflammatory oxidant derived from neutrophil myeloperoxidase, can chlorinate cytosolic proteins and nuclear DNA bases of target cells by passing through the cell membrane. However, little is known about the consequences of HOCl-derived modification of cell membrane components, including phospholipids. In this study, we characterize the reaction of HOCl with phospholipid molecules and found that aminophospholipids are the key molecules that chemically regulate lipid peroxidation. Upon incubation with HOCl, the peroxidation of egg yolk phosphatidylcholine was significantly enhanced in the presence of phosphatidylethanolamine (PE). In contrast, the peroxidation was significantly inhibited in the presence of phosphatidylserine (PS). On the basis of mass spectrometric and electron paramagnetic resonance characterization, the initiator of the peroxidation was identified as the nitrogen-centered radical originating from PE-derived chloramines, especially N,N-dichlorinated PE, a major product in the HOCl-modified PE. Although PS was also chlorinated upon reaction with HOCl, the formed chloramine rapidly decomposed to phosphatidylglycolaldehyde, a novel class of lipid aldehyde. Formation of phosphatidylglycolaldehyde was also confirmed in the porcine brain PS and erythrocyte cell membrane ghost exposed to HOCl. These results provide a novel mechanism for the HOCl-induced oxidative damage and its endogenous protection in the cell membrane at the site of inflammation.
(Keyword)
Chromatography, High Pressure Liquid / Chromatography, Thin Layer / Gas Chromatography-Mass Spectrometry / Hypochlorous Acid / Lipid Peroxidation / Mass Spectrometry / Phospholipids / Spectrophotometry, Ultraviolet
Kenji Fukuzawa, Aya Fujisaki, Kaori Akai, Akira Tokumura, Junji Terao and Jansuz M. Gebicki : Measurement of phosphatidylcholine hydroperoxides in solution and in intact membranes by the ferric-xylenol orange assay, Analytical Biochemistry: Methods in the Biological Sciences, Vol.359, No.1, 18-25, 2006.
(Summary)
Formation of a colored complex between ferric iron and xylenol orange (XO) has been used for the determination of hydroperoxides (FOX method). Original or modified FOX methods were performed on aqueous or organic solutions consisting of a single phase. However, for lipid peroxides in heterogeneous samples, such as biological materials, much of the lipid is sequestered in a separate phase. Organic solvent extraction of these lipids is often incomplete and may result in additional peroxidation during the extraction procedure. In this study, we applied the FOX assay for measurement of the membrane phosphatidylcholine hydroperoxides (PC-OOH) in separated phases. The presence of membranous egg yolk phosphatidylcholine (EYPC) in 60% MeOH shifted the broad peak at 560 nm of Fe(3+)-XO complex to 610 nm with a sharp peak associated with the increased intensity of the absorbance. The shift of the peak is useful to measure the unknown amounts of Fe(3+) because the uncomplexed XO considerably contributed to the absorbance of the peak at 560 nm but did not affect the absorbance at 610 nm. EYPC was required to form the membranes to shift the peak because the shift occurred in 60% MeOH but did not by the treatment with detergents or in 90% MeOH in which EYPC did not form the membranes. The molar absorption coefficient (epsilon 610) was 32,700 M(-1) cm(-1), which was about twice the molar absorption co efficient (epsilon 560) reported. We applied this method to the assay of PC-OOH prepared from EYPC and obtained the molar absorption coefficients (epsilon 610), which were 79,100 and 115,700 M(-1) cm(-1) in the presence and absence of BHT, respectively. This finding allows the determination of PC-OOH concentration even in chemically complex systems.
Mutsuko Shirai, Yoshichika Kawai, Rintaro Yamanishi, Takashi KInoshita, Hiroshi Chuman and Junji Terao : Effect of a conjugated quercetin metabolite, quercetin 3-glucuronide, on lipid hydroperoxide-dependent formation of reactive oxygen species in differentiated PC-12 cells, Free Radical Research, Vol.40, No.10, 1047-1053, 2006.
(Summary)
To assess the efficacy of conjugated quercetin metabolites as attenuators for oxidative stress in the central nervous system, we measured the 13-hydroperoxyoctadecadienoic acid (13-HPODE)-dependent formation of reactive oxygen species (ROS) in pheochromocytoma PC-12 cells in the presence of quercetin 3-O-beta-glucuronide (Q3GA) and related compounds. A 2',7'-dichlorofluorescin (DCFH) assay showed that Q3GA significantly suppressed the formation of ROS, when it was coincubated with 13-HPODE (coincubation system). However, it was less effective than quercetin aglycon in the concentration range from 0.5 to 10 microM. In an experiment in which the cells were incubated with the test compounds for 24 h before being exposed to 13-HPODE, Q3GA was also effective in suppressing the formation of ROS in spite that little Q3GA was taken up into the cells. These results suggest that antioxidative metabolites of quercetin are capable of protecting nerve cells from attack of lipid hydroperoxides.
Vegetables contain a variety of flavonoids, such as flavonols, flavones and anthocyanidins. Numerous in vitro studies have revealed diverse biochemical actions of flavonoids, and their antioxidant activity should be, at least partly, responsible for these actions. We are interested in quercetin (3, 3', 4', 5, 7-pentahydroxyflavone), a flavonol-type flavonoid as an anti-atherosclerotic food factor and have examined its bioavailability to evaluate the biological effect. Quercetin and other flavonoids frequently exist as their glycoside forms in vegetables. Glucoside-bound quercetin is absorbed and hydrolyzed in small intestine through glucose-transport system or passive transport after lactase phlorizin hydrolase (LPH)-dependent deglucosidation. Quercetin glycosides other than glucoside forms are likely to be absorbed in large intestine after hydrolysis with enterobacteria. Efficiency of the absorption is considerably affected by the coexisting food components. Lipids and emulsifiers were found to enhance the absorption. In any cases, resulting quercetin aglycone is converted to conjugated glucuronides and/or sulfates during the process of their absorption. Some metabolites circulating in the blood stream can act as free radical scavengers, as well as the inhibitors of lipoxygenase and xanthine oxidase. It is therefore likely that biological effect of quercetin is originated from conjugated metabolites. Metabolic conversion of flavonoids to their conjugates may be a process for regulating their action on cellular oxidative stress.
Hiroyuki Sakakibara, Kaori Ishida, Oliver Grundmann, Jun-ichiro Nakajima, Shujiro Seo, Veronika Butterweck, Yuko Minami, Satomi Saito, Yoshichika Kawai, Yutaka Nakaya and Junji Terao : Antidepressant effect of extracts from Ginkgo biloba leaves in behavioral models, Biological & Pharmaceutical Bulletin, Vol.29, No.8, 1767-1770, 2006.
(Summary)
Extracts of Ginkgo biloba (EGB) are a complex product prepared from green leaves of the Ginkgo biloba tree. In the present study, the antidepressant effect of EGB was examined using two behavioral models, the forced swimming test (FST) in rats and tail suspension test (TST) in mice. EGB significantly reduced immobility time in the FST at a dosage of 10 and 50 mg/kg body weight after repeated oral treatment for 14 d, although no change of motor dysfunction was observed with the same dosage in the open field test. These results indicate that EGB might possess an antidepressant activity. In addition, EGB markedly shortened immobility time in the TST after acute inter-peritoneal treatment at a dosage of 50 and 100 mg/kg body weight. The present study clearly demonstrated that EGB exerts an antidepressant effect in these two behavioral models.
Yoshihiro Uto, Shutaro Ae, Azusa Hotta, Junji Terao, Hideko Nagasawa and Hitoshi Hori : Artepillin C isoprenomics: design and synthesis of artepillin C analogues as antiatherogenic antioxidants, Advances in Experimental Medicine and Biology, Vol.578, 113-118, 2006.
Yamamoto Masako, Miyamoto Sayuri, Jae-Hak Moon, Kaeko Murota, Hara Yukihiko and Junji Terao : Effect of Dietary Green Tea Catechin Preparation on Oxidative Stress Parameters in Large Intestinal Mucosa of Rats, Bioscience, Biotechnology, and Biochemistry, Vol.70, No.1, 286-289, 2006.
(Summary)
Intake of green tea catechin (GTC) for 4 weeks was found to elevate vitamin E level in the mucosa of the rat large intestine. Iron-induced lipid peroxidation of the mucosal homogenate was suppressed by intake of GTC in rats fed monounsaturated fatty acid (MUFA), indicating that the protective effect of dietary GTC on mucosal oxidative stress is enhanced by combination with a MUFA-rich diet.
(Keyword)
Animals / catechin / color / Diet / Intestinal Mucosa / Intestine, Large / lipid peroxidation / Male / oxidative stress / Rats / Rats, Wistar / Tea / vitamin E
Takashi Kinoshita, Lepp Zsolt, Yoshichika Kawai, Junji Terao and Hiroshi Chuman : An Integrated Database of Flavonoids, BioFactors, Vol.26, No.3, 179-188, 2006.
(Summary)
Flavonoids are polyphenolic compounds that occur ubiquitously in foods of plant origin. Some of these molecules exhibit various physiological activities. Among existing drugs, there are a huge number of compounds bearing a flavonoid-related skeleton. Because of the relevance for pharmaceutical research, it would be beneficial to collect these compounds into a database. Recently, various databases of chemicals were compiled to help biological and/or chemical research, but no comprehensive database of flavonoids with chemical structures and physicochemical parameters, supposedly related to their activity, is available yet. The aim of this research was to merge the information about flavonoids of plant origin and flavonoids used as medicines into a database. Moreover, predictions of activities against various targets were performed using a virtual screening procedure to demonstrate a possible application of the database for pharmaceutical research.
(Keyword)
physical chemistry / Databases, Factual / Drug Design / flavonoids / Lipoxygenase / molecular structure / Predictive Value of Tests / Reproducibility of Results / structureactivity relationship
(Link to Search Site for Scientific Articles)
● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 16971749
Mikiko Ito, Sakiko Haito, Mari Furumoto, Yoshichika Kawai, Junji Terao and Ken-ichi Miyamoto : Approach to novel functional foods for stress control 4. Regulation of serotonin transporter by food factors, The Journal of Medical Investigation : JMI, Vol.52, No.0, 245-248, 2005.
(Summary)
Serotonin transporters (SERTs) are pre-synaptic proteins specialized for the clearance of serotonin following vesicular release at central nervous system (CNS) and enteric nervous system synapses. SERTs are high affinity targets in vivo for antidepressants such as serotonin selective reuptake inhibitors (SSRIs). These include 'medical' psychopharmacological agents such as analgesics and antihistamines, a plant extract called St John's Wort (Hypericum). Osteoclasts are the primary cells responsible for bone resorption. They arise by the differentiation of osteoclast precursors of the monocyte/macrophage lineage. The expression of SERTs was increased in RANKL-induced osteoclast-like cells. Using RANKL stimulation of RAW264.7 cells as a model system for osteoclast differentiation, we studied the direct effects of food factor on serotonin uptake. The SSRIs (fluoxetine and fluvoxamine) inhibited markedly (approximately 95%) in serotonin transport in differentiated osteoclast cells. The major components of St. John's Wort, hyperforin and hypericine were significantly decreased in serotonin transport activity. Thus, a new in vitro model using RANKL-induced osteoclast-like cells may be useful to analyze the regulation of SERT by food factors and SSRIs.
Mutsuko Shirai, Yoshichika Kawai, Rintaro Yamanishi and Junji Terao : Approach to novel functional foods for stress control 5. Antioxidant activity profiles of antidepressant herbs and their active components, The Journal of Medical Investigation : JMI, Vol.52, 249-251, 2005.
(Summary)
Oxidative stress is frequently mentioned in relation to the neurodegenerative diseases. This study examined the effect of three herb extracts, Hypericum perforatum, Ginkgo biloba L. and Apocynum venetum L., and their components on lipid hydroperoxide-induced oxidative stress in PC-12 cells. Among them, the extract of Apocynum venetum and its components showed the remarkable inhibitory effect, indicating that this herb extract serves as a protective agent against lipid peroxidation-related oxidative stress in CNS. Oxidative stress may be associated with the progress of depression, as this extract has been proposed to be an effective antidepresant herb.
Hiroyuki Sakakibara, Kaori Ishida, Yuki Izawa, Yuko Minami, Satomi Saito, Yoshichika Kawai, Veronika Butterweck, Toshiaki Tamaki, Yutaka Nakaya and Junji Terao : Effects of forced swimming stress on rat brain function, The Journal of Medical Investigation : JMI, Vol.52, No.Suppl., 300-3001, 2005.
(Summary)
Chronic stress has been reported to be an essential factor for depression. In this study, the effect of forced swimming stress on neurotransmitters and cellular signaling pathway contributing to brain functions was investigated using the forced swimming test (FST) in order to understanding of mechanisms to regulate stress signals in brain. Antidepressant drug, imipramine, significantly reduced the immobility time of male rats in the FST by 85% at a dose of 15 mg/kg for 2 weeks. This result indicated that the swimming stress caused a depressed state in the rats without administration of imipramine. Swimming stress significantly lowered the serotonergic ratio and also markedly enhanced the phosphorylation of ERK1/2 in the hypothalamus region compared to the rats without FST. These phenomena may be included in key mechanisms of the development of depression.
(Keyword)
Animals / Antidepressive Agents, Tricyclic / brain / Chromatography, High Pressure Liquid / Enzyme Activation / Hippocampus / Hydroxyindoleacetic Acid / Imipramine / Immunoblotting / Male / Mitogen-Activated Protein Kinase 3 / Motor Activity / phosphorylation / Rats / Rats, Inbred Strains / Serotonin / signal transduction / Stress, Physiological / Swimming / Time Factors
Kaeko Murota and Junji Terao : Quercetin appears in the lymph of unanesthetized rats as its phase II metabolites after administered into the stomach, FEBS Letters, Vol.579, No.24, 5343-5346, 2005.
(Summary)
Quercetin is a major flavonoid in plant foods and potentially has beneficial effects on disease prevention. The present work demonstrated that quercetin was transported into the lymph after being metabolized in the gastrointestinal mucosa of rats. Glucuronide/sulfate and methylated conjugates of quercetin appeared in the lymph, but not quercetin aglycone. The highest lymphatic concentration was found at as rapid as 30 min after administration, suggesting gastric absorption, whereas the mucosal glucuronidation activity was significantly higher in the duodenum and jejunum than in the stomach. This is the first report to show the lymphatic flavonoid transport pathway from the gastrointestinal tract.
(Keyword)
Animals / Drug Administration Routes / lymphocyte / Male / Quercetin / Rats / Rats, Wistar / Stomach
Sohji Nagase, Aki Hirayama, Atsushi Ueda, Kouichi Hirayama, Junji Terao and Akio Koyama : Does fluvastatin really have an antioxidant effect in humans?, Kidney International, Vol.68, No.3, 1373-1374, 2005.
G. Williamson, D. Barron, K. Shimoi and Junji Terao : In vitro biological properties of flavonoid conjugates found in vivo, Free Radical Research, Vol.39, No.5, 457-469, 2005.
(Summary)
For some flavonoids such as quercetin, isoflavones and catechins, the pathways of absorption and metabolism are now reasonably well characterised and understood. By definition, for biological activity of flavonoids to be manifest, the target tissue, which includes the blood and vascular system, must respond to the form(s) of flavonoid that it encounters. Bioavailability studies have shown that the circulating form of most flavonoids is as conjugates, with a few notable exceptions. There have been several recent papers on the in vitro biological properties of conjugates that have been found in vivo. This paper reviews the properties of these conjugates. Most of the information currently available is on quercetin glucuronides, but also on isoflavone and catechin conjugates. In addition to the biological properties of the conjugates, the partition coefficients and methods of synthesis are also presented.
Chiemi Kamada, Edson da L. Silva, Mayumi Ohnishi-Kameyama, Jae-Hak Moon and Junji Terao : Attenuation of lipid peroxidation and hyperlipidemia by quercetin glucoside in the aorta of high cholesterol-fed rabbit, Free Radical Research, Vol.39, No.2, 185-194, 2005.
(Summary)
Antioxidative activity of dietary flavonoids is suggested to be, at least partly, responsible for a wide variety of their biological effects relating to anti-atherosclerosis. However, it is not known whether dietary flavonoids reach to the target site and act as antioxidants. In this study, we tried to evaluate the antioxidative effect of quercetin 3-O-beta-D-glucoside (Q3G), a typical flavonoid present in vegetables, in rabbit aorta. New Zealand White rabbits were fed a control diet (control group), 2.0% cholesterol diet (HC group) and 2.0% cholesterol plus 0.1% Q3G (HC + Q3G group) for one month. The amounts of total cholesterol, triacylglycerol and total fatty acids in both the plasma and aorta were significantly lower in the HC + Q3G group as compared with the HC group. Quercetin was detected in the aorta of the HC + Q3G group after enzymatic deconjugation, indicating that quercetin accumulated as conjugated metabolites in the aorta. The contents of TBA-reacting substances (TBARS) and cholesteryl ester hydroperoxides (CEOOH) in the aorta of the HC + Q3G group were significantly lower than those in the HC group. The aorta of HC + Q3G group was more resistant than that of HC group in copper ion-induced lipid peroxidation ex vivo. HC + Q3G group accumulated a higher amount of vitamin E per total cholesterol than HC group in the aorta. These results strongly suggest that quercetin glucosides accumulate in the aorta as their metabolites and attenuate lipid peroxidation occurring in the aorta, along with the attenuation of hyperlipidemia.
Seigo Baba, Naomi Osakabe, Midori Natsume, Akiko Yasuda, Yuko Muto, Kyoko Hiyoshi, Hirohisa Takano, Toshikazu Yoshikawa and Junji Terao : Absorption, metabolism, degradation and urinary excretion of rosmarinic acid after intake of Perilla frutescens extract in humans, European Journal of Nutrition, Vol.44, No.1, 1-9, 2005.
(Summary)
Rosmarinic acid (RA) is a natural polyphenolic substance contained in many Lamiaceae herbs such as Perilla frutescens. Previous studies have shown RA has antioxidative and anti-inflammatory activity. However, little is known on the absorption, metabolism, degradation and excretion of RA. The aim of this study in healthy humans was to determine the absorption, metabolism, and urinary excretion of RA after a single intake of perilla extract (PE). Six healthy men (mean age 37.2 +/- 6.2 y and mean body mass index 22.0 +/- 1.9 kg/m(2)) were enrolled in the study that was a crossover design involving single intakes of PE containing 200 mg RA and placebo with a 10 day interval between treatments. Blood samples were collected before intake and at designated time intervals, while urine samples were collected over the periods 0-6 h, 6-24 h and 24-48 h after intake. RA and its related metabolites in plasma and urine were measured by LC-MS. RA, methylated RA (methyl-RA), caffeic acid (CAA), ferulic acid (FA) and a trace of m-coumaric acid (COA) were detected in the urine after intake of PE. In plasma, RA, methyl-RA and FA were detected, with maximum levels obtained 0.5, 2 and 0.5 h after intake of PE, respectively. The majority of these components in both plasma and urine were present as conjugated forms (glucuronide and/or sulfated). The proportion of RA and its related metabolites excreted in the urine was 6.3 +/- 2.2% of the total dose, with approximately 75% of these components being excreted within 6 h after intake of PE. RA contained in PE was absorbed, conjugated and methylated following intake, with a small proportion of RA being degraded into various components, such as conjugated forms of CAA, FA and COA. These metabolites were then rapidly excreted in the urine.
Junji Terao, Mio Hiwada, Keiko Taguchi, Keigo Takahara and Satoshi Mohri : Glutathione peroxidase mimics as novel antioxidants from vegetables, BioFactors, Vol.23, No.1, 1-6, 2005.
(Summary)
Vegetables are generally recognized as rich sources of dietary antioxidants for inhibiting lipid peroxidation. Here we investigated lipid hydroperoxide (LOOH)-reducing activity of several vegetables to estimate their role on the prevention of lipid peroxidation in food and the digestive tract. By using HPLC analysis, we screened vegetables possessing the ability to convert 13-hydroperoxyoctadecadienoic acid (13-HPODE) to its reduced derivative, 13-hydroxyoctadecadienoic acid (13-HODE). Welsh onion (Allium fistulosum L.) was found to be highly active in the reduction of 13-HPODE among tested vegetables. There was no relationship between 13-HPODE reducing activity and GSH peroxidase (GPX) activity in the tested vegetables. 13-HPODE-reducing activity of welsh onion was enhanced by the addition of sulfhydryl compounds including glutathione (GSH). Neither GPX inhibitor nor heat treatment suppressed 13-HPODE-reducing activity effectively. These results suggest that welsh onion and other vegetables contain GPX mimics responsible for the reduction of LOOH. GPX mimics may be helpful in the attenuation of harmful effect of LOOH from food.
Midori Natsume, Naomi Osakabe, Akiko Yasuda, Seigo Baba, Takashi Tokunaga, Kazuo Kondo, Toshihiko Osawa and Junji Terao : In Vitro Antioxidative Activity of (-)-Epicatechin Glucuronide Metabolites Present in Human and Rat Plasma, Free Radical Research, Vol.38, No.12, 1341-1348, 2004.
(Summary)
Recently we identified four conjugated glucuronide metabolites of epicatechin, (-)-epicatechin-3'-O-glucuronide (E3'G), 4'-O-methyl-(-)-epicatechin-3'-O-glucuronide (4'ME3'G), (-)-epicatechin-7-O-glucuronide (E7G) and 3'-O-methyl-(-)-epicatechin-7-O-glucuronide (3'ME7G) from plasma and urine. E3'G and 4'ME3'G were isolated from human urine, while E7G and 3'ME7G were isolated from rats that had received oral administration of (-)-epicatechin (Natsume et al. (2003), Free Radic. Biol. Med. 34,840-849). It has been suggested that these metabolites possess considerable in vivo activity, and therefore we carried out a study to compare the antioxidant activities of the metabolites with that of the parent compound. This was achieved by measuring superoxide scavenging activity, reduction of plasma TBARS production and reduced susceptibility of low-density-lipoprotein (LDL) to oxidation. (-)-Epicatechin was found to have more potent antioxidant activity than the conjugated glucuronide metabolites. Both (-)-epicatechin and E7G had marked antioxidative properties with respect to superoxide radical scavenging activity, plasma oxidation induced by 2,2'-azobis-(2-aminopropane) dihydrochloride (AAPH) and LDL oxidation induced by copper ions or 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (MeO-AMVN). In contrast, the other metabolites had light antioxidative activities over the range of physiological concentrations found in plasma.
Noriko Bando, Hiroki Hayashi, Saori Wakamatsu, Takahiro Inakuma, Mariko Miyoshi, Akihiko Nagao, Ryo Yamauchi and Junji Terao : Participation of singlet oxygen in ultraviolet-a-induced lipid peroxidation in mouse skin and its inhibition by dietary β-carotene: an ex vivo study, Free Radical Biology and Medicine, Vol.37, No.11, 1854-1863, 2004.
Eiji Takeda, Junji Terao, Yutaka Nakaya, Ken-ichi Miyamoto, Yoshinobu Baba, Hiroshi Chuman, Ryuji Kaji, Tetsuro Ohmori and Kazuhito Rokutan : Stress control and human nutrition, The Journal of Medical Investigation : JMI, Vol.51, No.3-4, 139-145, 2004.
(Summary)
Stress is a pervasive factor in everyday life that critically affects development and functioning. Severe and prolonged stress exposure impairs homeostatic mechanisms, particularly associated with the onset of depressive illness. Brain food is aimed at preventing as well as treating a growing number of stress-related mental disorders. Some topics on the association of stress and nutrition is reviewed. (1) An increased activity of serotonergic neurons in the brain is an established consequence of stress. An increase in brain tryptophan levels on the order of that produced by eating a carbohydrate-rich/protein-poor meal causes parallel increases in the amounts of serotonin released into synapses. (2) Eating is thought to be suppressed during stress, due to anorectic effects of corticotrophin releasing hormone, and increased during recovery from stress, due to appetite stimulating effects of residual cortisol. (3) A strong inverse association between coffee intake and risk of suicide. (4) Night eating syndrome has been found to occur during periods of stress and is associated with poor results at attempts to lose weight and disturbances in the hypothalamic-pituitary-adrenal axis. (5) Dietary antioxidants present in fruits and vegetables may improve cognitive function. Therefore, it is concluded that the establishment of functional foods that correctly regulate stress response must be firmly based upon scientific knowledge and legal regulation.
Kaeko Murota, Yuki Mitsukuni, Mami Ichigawa, Tojiro Tsushida, Miyamoto Sayuri and Junji Terao : Quercetin-4'-glucoside is more potent than quercetin-3-glucoside in protection of rat intestinal mucosa homogenates against iron ion-induced lipid peroxidation, Journal of Agricultural and Food Chemistry, Vol.52, No.7, 1907-1912, 2004.
(Summary)
Quercetin is a typical antioxidative flavonoid found in vegetables, which is more commonly present as its glucosides, quercetin-3-glucoside (Q3G) and quercetin-4'-glucoside (Q4'G). The main aim of this study was to estimate the antioxidant activity of Q3G and Q4'G on iron ion-driven lipid peroxidation of the gastrointestinal mucosa. Q4'G markedly suppressed the lipid peroxidation when rat gastrointestinal mucosa homogenates were incubated with Fe(NO3)3 and ascorbic acid. Its effectiveness was greater as compared to that of Q3G and comparable to that of quercetin aglycone. Furthermore, Q4'G yielded higher amounts of quercetin aglycone than Q3G on incubation with the homogenates. However, Q4'G showed a lower chelating activity in comparison to Q3G. These results indicate that Q4'G, even though it has a low chelating activity, because of its efficient conversion to antioxidative aglycone on exposure to the mucosa, can act as a powerful antioxidant on iron ion driven lipid peroxidation in the intestinal mucosa. Thus, vegetables rich in Q4'G, such as onion, are likely to serve as favorable antioxidant sources for suppressing iron-induced oxidative stress in the intestinal tract.
(Keyword)
Animals / Antioxidants / Intestinal Mucosa / Iron / lipid peroxidation / Male / Quercetin / Rats / Rats, Wistar
Seigo Baba, Naomi Osakabe, Midori Natsume and Junji Terao : Orally administered rosmarinic acid is present as the conuugated and/or methylated forms in plasma, and is degrade and metabolized to conjugated forms of caffeic acid, ferulic acid and m-coumaric acid, Life Sciences, Vol.75, No.2, 165-178, 2004.
(Summary)
Rosmarinic acid (RA) is contained in various Lamiaceae herbs used commonly as culinary herbs. Although RA has various potent physiological actions, little is known on its bioavailability. We therefore investigated the absorption and metabolism of orally administered RA in rats. After being deprived of food for 12 h, RA (50 mg/kg body weight) or deionized water was administered orally to rats. Blood samples were collected from a cannula inserted in the femoral artery before and at designated time intervals after administration of RA. Urine excreted within 0 to 8 h and 8 to 18 h post-administration was also collected. RA and its related metabolites in plasma and urine were measured by LC-MS after treatment with sulfatase and/or beta-glucuronidase. RA, mono-methylated RA (methyl-RA) and m-coumaric acid (COA) were detected in plasma, with peak concentrations being reached at 0.5, 1 and 8 h after RA administration, respectively. RA, methyl-RA, caffeic acid (CAA), ferulic acid (FA) and COA were detected in urine after RA administration. These components in plasma and urine were present predominantly as conjugated forms such as glucuronide or sulfate. The percentage of the original oral dose of RA excreted in the urine within 18 h of administration as free and conjugated forms was 0.44 +/- 0.21% for RA, 1.60 +/- 0.74% for methyl-RA, 1.06 +/- 0.35% for CAA, 1.70 +/- 0.45% for FA and 0.67 +/- 0.29% for COA. Approximately 83% of the total amount of these metabolites was excreted in the period 8 to 18 h after RA administration. These results suggest that RA was absorbed and metabolized as conjugated and/or methylated forms, and that the majority of RA absorbed was degraded into conjugated and/or methylated forms of CAA, FA and COA before being excreted gradually in the urine.
(Keyword)
Administration, Oral / Animals / Caffeic Acids / Catechol O-Methyltransferase / Chromatography, High Pressure Liquid / Cinnamates / Coumaric Acids / Depsides / Glucuronidase / Male / mass spectrometry / Methylation / Models, Chemical / Nuclear Magnetic Resonance, Biomolecular / Rats / Rats, Sprague-Dawley / Sulfatases
Mika Mochizuki, Katsuko Kajiya, Junji Terao, Kazuhiko Kaji, Shigenori Kumazawa, Tsutomu Nakayama and Kayoko Shimoi : Effect of quercetin conjugates on vascular permeability and expression of adhesion molecules, BioFactors, Vol.22, No.1-4, 201-204, 2004.
(Summary)
Quercetin and its glucosides exist in plant foods and are recovered in human plasma as glucuronide and sulfate conjugates. Quercetin and its conjugates show antioxidant activity in model experiments. It remains obscure, however, whether these conjugates retain these biological functions in vivo. We investigated the interaction of quercetin conjugates with lipid bilayers using liposome systems. Less quercetin conjugate was incorporated into liposomes than quercetin aglycone. We also studied the vascular permeability of quercetin-3-glucuronide using cell culture inserts. Incubation of human aortic endothelial cells (HAECs) with IL-1alpha resulted in increased permeability of quercetin-3-glucuronide. Furthermore, quercetin-3-glucuronide showed no suppressive effect on TNF-alpha-induced cell expression of intercellular adhesion molecule-1 (ICAM-1) on HAECs. These observations suggest that circulating conjugates of quercetin pass through the endothelium to reach vascular smooth muscle cells and exert their biological effects in the blood vessels during inflammation followed by deconjugation of the conjugates.
Keiko AZUMA, Katsunari IPPOUSHI, Hidekazu ITO, Hideki HORIE and Junji Terao : Enhancing Effect of Lipids and Emulsifiers on the Accumulation of Quercetin Metabolites in Blood Plasma after the Short-term Ingestion of Onion by Rats, Bioscience, Biotechnology, and Biochemistry, Vol.67, No.12, 2548-2555, 2003.
(Summary)
The effects of co-ingested lipids and emulsifiers on the accumulation of quercetin metabolites in blood plasma after the short-term ingestion of onion by rats were investigated. Plasma extracts of rats that had been fed onion-containing diets for one and two weeks were analyzed by HPLC with electrochemical detection after a treatment with sulfatase/β-glucuronidase. Almost all of the quercetin metabolites in the plasma were sulfate/glucuronide conjugates of quercetin and isorhamnetin. More than 4.6% (w/w) of soybean oil in the diets significantly enhanced the accumulation of quercetin metabolites in the plasma. Fish oil and beef tallow increased this to an extent similar to that with soybean oil, and lecithin was more effective than the other three lipids. Two emulsifiers, sodium caseinate and sucrose fatty acid ester, also showed an enhancing effect on the accumulation of quercetin metabolites. These results indicate that co-ingested lipids and emulsifiers could enhance the bioavailability of quercetin glucosides in onion.
Rintaro Yamanishi, Ikuko Yusa, Akiko Miyamoto, Izumi Sato, Noriko Bando and Junji Terao : Alum Augments the Experimental Allergenicity of Kunitz-Type Soybean Trypsin Inhibitor Independent of the Antigen-Adsorption, Journal of Nutritional Science and Vitaminology, Vol.49, No.6, 409-413, 2003.
(Summary)
In order to inspect the significance of the adsorbing property in the adjuvant activity to enhance IgE production, we immunized BALB/c mice against Kunitz-type soybean trypsin inhibitor (KSTI), the most potent experimental allergen among soybean proteins, associated with Aluminum hydroxide (alum) or DEAE-Sephadex particles. The production of immunoglobulin isotypes was analyzed at the various amounts, 3-3, 000μg per mouse, of the antigen dosages. In our experiments, although alum did not adsorb KSTI significantly, it augmented the total and the antigen-specific IgE without affecting the optimal range of the antigen dosage. On the other hand, alum did not effectively enhance the production of the other immunoglobulin isotypes. The production of immunoglobulin isotypes other than IgE increased dose-dependently on the antigen. These results ensured our previous finding that another protein, ovalbumin, was used as the antigen. We also demonstrated that the adsorption of KSTI by DEAE-Sephadex in the immunizing vehicle resulted in the requirement of more KSTI for accomplishing the equal immunity in BALB/c mice compared to the control. Moreover, we demonstrated that, regardless of the inability to adsorb KSTI, alum exerted its adjuvant activity only when it was co-injected with the antigen. These results showed that some biochemical effect, other than adsorptive activity, to enhance the production of the antigen-specific IgE resides in alum.
Noriko Bando, Rintaro Yamanishi and Junji Terao : Inhibition of Immunoglobulin E Production in Allergic Model Mice by Supplementation with Vitamin E and β-Carotene, Bioscience, Biotechnology, and Biochemistry, Vol.67, No.10, 2176-2182, 2003.
(Summary)
A diet containing different amounts of vitamin E (α-tocopherol ; 0.5 mg, 5 mg, 10 mg or 50 mg per 100 g diet) was supplemented to BALB/c mice for 6 weeks. These mice were subcutaneously immunized twice with ovalbumin (OVA). A passive cutaneous anaphylaxis (PCA) analysis demonstrated that the mice fed on the diet containing 5 mg of vitamin E produced the highest level of the OVA-specific immunoglobulin E (IgE) antibody. A lower level of serum IgE was found in the mice supplemented with 0.5 mg, 10 mg and 50 mg of vitamin E. A sandwich ELISA analysis showed that the pattern of the total IgE antibody level among these four groups was the same as that of the allergen-specific IgE. In a separate experiment, 5 mg of vitamin E and/or 50 mg of β-carotene was supplemented to the basal diet containing vitamin E as α-tocopherol acetate (5 mg) in order to evaluate the effect of their combination on OVA-specific and total IgE production in the mice. The supplementation with β-carotene alone had no effect on OVA-specific or total IgE production. In contrast, supplementation with vitamin E plus β-carotene effectively suppressed both the antigen-specific and total IgE antibodies. The serum vitamin E and β-carotene levels were increased by supplementation with the respective compounds. These results strongly suggest that the combination of dietary vitamin E and β-carotene suppressed IgE production and would therefore help to prevent the type-I allergic reaction.
Kaeko Murota and Junji Terao : Antioxidative flavonoid quercetin: Implication of its intestinal absorption and metabolism., Archives of Biochemistry and Biophysics, Vol.417, No.1, 12-17, 2003.
(Summary)
Quercetin is a typical flavonoid ubiquitously present in fruits and vegetables, and its antioxidant effect is implied to be helpful for human health. The bioavailability of quercetin glycosides should be clarified, because dietary quercetin is mostly present as its glycoside form. Although quercetin glycosides are subject to deglycosidation by enterobacteria for the absorption at large intestine, small intestine acts as an effective absorption site for glucose-bound glycosides (quercertin glucosides). This is because small intestinal cells possess a glucoside-hydrolyzing activity and their glucose transport system is capable of participating in the glucoside absorption. A study using a cultured cell model for intestinal absorption explains that the hydrolysis of the glucosides accelerates their absorption in the small intestine. Small intestine is also recognized as the site for metabolic conversion of quercetin and other flavonoids as it possesses enzymatic activity of glucuronidation and sulfation. Modulation of the intestinal absorption and metabolism may be beneficial for regulating the biological effects of dietary quercetin.
Sayuri Miyamoto, Coralie Dupas, Kaeko Murota and Junji Terao : Phospholipid hydroperoxides are detoxified by phospholipase A2 and GSH peroxidase in rat gastric mucosa, Lipids, Vol.38, No.6, 641-649, 2003.
(Summary)
The aim of this study was to determine the metabolic fate of phospholipid hydroperoxides (PLOOH) in rat gastric mucosa. Here we report evidence concerning the mechanism for PLOOH detoxification in gastric mucosa homogenate. Analysis by the TLC blot technique showed that the gastric mucosa has the highest potential to eliminate 1-palmitoyl-2-linoleoyl-phosphatidylcholine hydroperoxides (PL-PtdChoOOH) compared with the intestinal mucosa and liver. Major products detected after incubation with gastric mucosa were the partially reduced linoleic acid hydroperoxides (LAOOH) and lysophosphatidylcholine, indicating the involvement of phospholipase A2 (PLA2) in the elimination pathway. Using unilamellar vesicles, we demonstrated that gastric mucosal PLA2 does not distinguish between PLOOH and intact phospholipids. Although gastric mucosal PLA2 activity efficiently eliminated excess amounts of PLOOH, the complete reduction of LAOOH was dependent on the supply of exogenous GSH. In a separate experiment, administration of egg yolk PtdChoOOH to rats for 6 d significantly elevated GSH peroxidase (GPx) activity in the gastric mucosa. We concluded that excess amounts of PLOOH are efficiently eliminated through the hydrolysis by PLA2, and the subsequent reduction of FA hydroperoxide by GPx is the critical step for complete detoxification of oxidized phospholipids in the stomach.
Yoji KATO, Akihiko NAGAO, Junji Terao and Toshihiko OSAWA : Inhibition of Myeloperoxidase-catalyzed Tyrosylation by Phenolic Antioxidants in vitro, Bioscience, Biotechnology, and Biochemistry, Vol.67, No.5, 1136-1139, 2003.
(Summary)
We have developed an in vitro assay system for the evaluation of the inhibitory effects of phenolic antioxidants on myeloperoxidase (MPO) activity. The formation of dityrosine from the MPO/H_2O_2/L-tyrosine system was used as an indicator of the MPO activity. Because the buffer system used does not include chloride ion, this assay has the advantage of exclusion of direct reaction between an antioxidant and HOCl. In this assay, ferulic acid, gallic acid, and quercetin strongly inhibited the dityrosine formation, and curcumin and caffeic acid were also effective.
Midori Natsume, Naomi Osakabe, Makoto Oyama, Motoko Sasaki, Seigo Baba, Yoshimasa Nakamura, Toshihiko Osawa and Junji Terao : Structures of (-)-epicatechin glucuronide identified from plasma and urine after oral ingestion of (-)-epicatechin: differences between human and rat, Free Radical Biology and Medicine, Vol.34, No.7, 840-849, 2003.
(Summary)
(-)-epicatechin is one of the most potent antioxidants present in the human diet. Particularly high levels are found in black tea, apples, and chocolate. High intake of catechins has been associated with reduced risk of cardiovascular diseases. There have been several reports concerning the bioavailability of catechins, however, the chemical structure of (-)-epicatechin metabolites in blood, tissues, and urine remains unclear. In the present study, we purified and elucidated the chemical structure of (-)-epicatechin metabolites in human and rat urine after oral administration. Three metabolites were purified from human urine including (-)-epicatechin-3'-O-glucuronide, 4'-O-methyl-(-)-epicatechin-3'-O-glucuronide, and 4'-O-methyl-(-)-epicatechin-5 or 7-O-glucuronide, according to 1H- and 13C-NMR, HMBC, and LC-MS analyses. The metabolites purified from rat urine were 3'-O-methyl-(-)-epicatechin, (-)-epicatechin-7-O-glucuronide, and 3'-O-methyl-(-)-epicatechin-7-O-glucuronide. These compounds were also detected in the blood of humans and rats by LC-MS. The presence of these metabolites in blood and urine suggests that catechins are metabolized and circulated in the body after administration of catechin-containing foods.
(Keyword)
(-)-Epicatechin / Metabolites / Glucuronidation / rat / human / Free radicals
Rintaro Yamanishi, I. Yusa, Noriko Bando and Junji Terao : Adjuvant activity of alum in inducing antigen specific IgE antibodies in BALB/c mice: a Reevaluation, Bioscience, Biotechnology, and Biochemistry, Vol.67, No.1, 166-169, 2003.
(Summary)
The IgE production was compared in the presence and absence of aluminum hydroxide gel (alum). Without alum, the IgE production was induced within a suitable range of the antigen dosage; however, alum enhanced it. Alum did not affect the minimum requirement for the antigen dosage, indicating that alum may not take part in the efficiency of antigen presentation.
Relation between anemia resistant to recombinant human erythropoietin (rHuEPO) therapy and the oxidative stress in hemodialysis (HD) patients was investigated. Stable HD patients who had consistent hemoglobin concentrations on a constant dose of rHuEPO were studied. Patients were excluded if there were factors that might affect hemopoiesis or administration of antioxidant supplements. Patients were classified into three groups: High (9000 U/week), Low (1500-4500 U/week) and No rHuEPO group. Thiobarbituric acid reactive substances (TBARS) of sera and erythrocyte were examined. Serum superoxide and hydroxyl radical scavenging activities were measured using electron spin resonance. TBARS in the erythrocyte was higher in High rHuEPO group compared with No rHuEPO group, though the serum TBARS were similar. A diminution of serum hydroxyl radical scavenging activity was observed in High rHuEPO group. Hydroxyl radical signal intensity showed a strong correlation with the serum ferritin in High rHuEPO group, although ferritin concentrations were not different among the 3 groups. Superoxide scavenging activity showed no differences. These results indicate that increased lipid peroxidation in erythrocyte, raised by decreased serum hydroxyl radical scavenging activity, is one cause of rHuEPO resistant anemia. Serum ferritin may be involved in this hydroxyl radical production.
C.D. Dacaranhe and Junji Terao : Effect of Cabbage Phospholipase D Treatment on the Oxidative Stability of Beef Homogenate and Egg Yolk Phosphatidylcholine Liposomes, Journal of Food Science, Vol.67, No.7, 2619-2624, 2002.
Seigo Baba, Naomi Osakabe, Midori Natsume and Junji Terao : Absorption and urinary excretion of procyanidin B2 [epicatechin-(4β-8)-epicatechin] in rats, Free Radical Biology and Medicine, Vol.33, No.1, 142-148, 2002.
(Summary)
We evaluated the bioavailability and plasma antioxidative activity after administration of procyanidin B2 [epicatechin-(4beta-8)-epicatechin] in rats. After procyanidin B2 administration, procyanidin B2 is absorbed and excreted in urine, and a portion of the PB2 is degraded to (-)-epicatechin and to the metabolized conjugated and/or methylated (-)-epicatechin internally in the rat. Moreover, PB2 reduces the accumulation of lipid peroxide in plasma oxidized by copper ions.
Kaeko Murota, Sumie Shimizu, Sayuri Miyamoto, Toru Izumi, Akio Obata, Mamoru Kikuchi and Junji Terao : Unique uptake and transport of isoflavone aglycones by human intestinal caco-2 cells: comparison of isoflavonoids and flavonoids, The Journal of Nutrition, Vol.132, No.7, 1956-1961, 2002.
Masanori Yoshizumi, Koichiro Tsuchiya, Yuki Suzaki, Kazuyoshi Kirima, Moe Kyaw, Moon Jae-Hak, Junji Terao and Toshiaki Tamaki : Quercetin Glucronide prevents VSMC hypertrophy by angiotensin II via the inhibition of JNK and AP-1 signaling pathway., Biochemical and Biophysical Research Communications, Vol.293, No.5, 1458-1465, 2002.
(Summary)
We previously reported that quercetin, a bioflavonoid belonging to polyphenols, inhibited Angiotensin II (Ang II)-induced vascular smooth muscle cell (VSMC) hypertrophy through the inhibition of c-Jun N-terminal kinase (JNK) activation. However, we recently found that orally administered quercetin appeared in plasma as glucuronide-conjugated forms in rats and humans. Therefore we examined the effect of chemically synthesized quercetin glucuronide on Ang II-induced mitogen-activated protein (MAP) kinase activation and hypertrophy of cultured rat aortic smooth muscle cells (RASMC). Ang II activated extracellular signal-regulated kinase (ERK)1/2, JNK, and p38 in RASMC. Ang II-induced JNK activation was inhibited by quercetin 3-O-beta-d-glucuronide (Q3GA) whereas ERK1/2 and p38 activations were not affected. Q3GA scavenged 1,1-diphenyl-2-picrylhydrazyl radical measured by a method of electron paramagnetic resonance. Q3GA also inhibited Ang II-induced increases in activator protein-1 (AP-1) DNA binding, a downstream transcription factor of JNK. Finally, Ang II-induced [3H]leucine incorporation into RASMC was abolished by Q3GA. These findings suggest that the preventing effect of Q3GA on Ang II-induced VSMC hypertrophy is attributable in part to its inhibitory effect on JNK and the AP-1 signaling pathway. Q3GA would be an active metabolite of quercetin in plasma and may possess a preventing effect for cardiovascular diseases relevant to VSMC growth.
(Keyword)
Angiotensin II / Animals / Dimerization / Dose-Response Relationship, Drug / Electron Spin Resonance Spectroscopy / Enzyme Activation / Free Radicals / Glucuronides / Humans / JNK Mitogen-Activated Protein Kinases / Leucine / MAP Kinase Signaling System / Male / Mitogen-Activated Protein Kinase 1 / Mitogen-Activated Protein Kinase 3 / Mitogen-Activated Protein Kinases / Models, Chemical / Muscle, Smooth, Vascular / Protein Binding / Quercetin / Rats / Rats, Sprague-Dawley / Signal Transduction / Time Factors / Transcription Factor AP-1 / p38 Mitogen-Activated Protein Kinases
Norimasa Yoshida, Hironobu Murase, Tsutomu Kunieda, Shinya Toyokuni, Tomoyuki Tanaka, Junji Terao, Yuji Naito, Toru Tanigawa and Toshikazu Yoshikawa : Inhibitory effect of a novel water-soluble vitamin E derivative on atherosclerosis in rabbits, Atherosclerosis, Vol.162, No.1, 111-117, 2002.
(Summary)
A novel vitamin E derivative that is freely soluble in water, 2-(alpha-D-glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol (TMG), was evaluated for ability to inhibit development of atherosclerosis in Watanabe heritable hyperlipidemic (WHHL) rabbits or cholesterol-loaded New Zealand White rabbits. Although TMG rapidly entered the circulation blood after oral administration, the blood TMG concentration remained low, while neither TMG nor its metabolites appeared in the low-density lipoprotein (LDL) fraction. TMG did not decrease serum total cholesterol and the various lipoprotein-associated cholesterol fractions (very LDL-, or high-density lipoprotein- (HDL) cholesterol). TMG reduced the serum concentration of thiobarbituric acid-reactive substances (TBARS; an index of lipid peroxidation) in cholesterol-loaded rabbits but not WHHL rabbits. Nonetheless, TMG inhibited aortic atherosclerosis as effectively as probucol in both models. Our results indicate that TMG opposes progression of atherosclerosis not only by preventing oxidation of LDL, but also by presently unknown mechanisms. Even an antioxidant with no uptake by LDL apparently can inhibit development of atherosclerosis despite a very low serum concentration.
Akira Murakami, Daisuke Takahashi, Takashi Kinoshita, Koichi Koshimizu, Ha Won Kim, Akira Yoshihiro, Yoshimasa Nakamura, Suratwadee Jiwajinda, Junji Terao and Hajime Ohigashi : Zerumbone, a Southeast Asian ginger sesquiterpene, markedly suppresses free radical generation, proinflammatory protein production, and cancer cell proliferation accompanied by apoptosis: the ,ß-unsaturated carbonyl group is a prerequisite, Carcinogenesis, Vol.23, No.5, 795-802, 2002.
(Summary)
Zerumbone (ZER), a sesquiterpene from the edible plant Zingiber zerumbet Smith, has recently been found to suppress tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced Epstein-Barr virus activation in a potent manner. In the present study, we evaluated the anti-inflammatory and chemopreventive potentials of ZER in a variety of cell culture experiments. ZER effectively suppressed TPA-induced superoxide anion generation from both NADPH oxidase in dimethylsulfoxide-differentiated HL-60 human acute promyelocytic leukemia cells and xanthine oxidase in AS52 Chinese hamster ovary cells. The combined lipopolysaccharide- and interferon-gamma-stimulated protein expressions of inducible nitric oxide synthase and cyclooxygenase (COX)-2, together with the release of tumor necrosis factor-alpha, in RAW 264.7 mouse macrophages were also markedly diminished. These suppressive events were accompanied with a combined decrease in the medium concentrations of nitrite and prostaglandin E(2), while the expression level of COX-1 was unchanged. ZER inhibited the proliferation of human colonic adenocarcinoma cell lines (LS174T, LS180, COLO205, and COLO320DM) in a dose-dependent manner, while the growth of normal human dermal (2F0-C25) and colon (CCD-18 Co) fibroblasts was less affected. It also induced apoptosis in COLO205 cells, as detected by dysfunction of the mitochondria transmembrane, Annexin V-detected translocation of phosphatidylserine, and chromatin condensation. Intriguingly, alpha-humulene, a structural analog lacking only the carbonyl group in ZER, was virtually inactive in all experiments conducted, indicating that the alpha,beta-unsaturated carbonyl group in ZER may play some pivotal roles in interactions with unidentified target molecule(s). Taken together, our results indicate that ZER is a food phytochemical that has distinct potentials for use in anti-inflammation, chemoprevention, and chemotherapy strategies.
Begum Nahar Aynun and Junji Terao : Protective effect of quercetin against cigarette tar extract-induced impairment of erythrocyte deformability, The Journal of Nutritional Biochemistry, Vol.13, No.5, 265-272, 2002.
(Summary)
Quercetin (3,3',4',5,7-pentahydroxyflavone) is one of the most abundant flavonol-type flavonoids rich in diet and suggested to possess a beneficial role in blood circulation. This study was conducted to know the effect of quercetin aglycone and one of its possible metabolite, quercetin-3-O-beta-D-glucuronide on cigarette tar extract-induced impairment of erythrocyte deformability. Erythrocyte suspension containing quercetin aglycone, quercetin-3-O-beta-D-glucuronide or quercetin-3-O-beta-D-glucoside was forced to flow through microchannels with equivalent diameter of 7 &mgr;m and its transit time was measured as an index of erythrocyte deformability using microchannel array method. Both quercetin aglycone and quercetin-3-O-beta-D-glucuronide, but not quercetin-3-O-beta-D-glucoside, substantially increased erythrocyte deformability indicating that the former two compounds affect the physicochemical state of erythrocyte by interacting with its membranes. Aqueous cigarette tar extract caused marked decrease in erythrocyte deformability with concomitant increase of membranous lipid peroxidation. In that case, quercetin aglycone suppressed the impairment of erythrocyte deformability as well as membranous lipid peroxidation. The same effect was found in quercetin-3-O-beta-D-glucuronide, eventhough its effect was lower than that of quercetin aglycone. Thus, not only quercetin aglycone but also its conjugate metabolite protects erythrocyte membrane from the damage of smoking by scavenging reactive oxygen species generated from cigarette tar. Intake of quercetin-rich food may be helpful to protect membranous damage in erythrocytes from smoking.
Mutauko Shirai, Rintaro Yamanishi, Jae-Hak Moon, Kaeko Murota and Junji Terao : Effect of Quercetin and its conjugated metabolite on the hydrogen peroxide-induced intracellular production of reactive oxygen species in mouse fibroblasts, Bioscience, Biotechnology, and Biochemistry, Vol.66, No.5, 1015-1021, 2002.
(Summary)
To clarify the antioxidative role of quercetin metabolites in cellular oxidative stress, we measured the inhibitory effects of the quercetin aglycon and quercetin 3-O-beta-D-glucuronide (Q3GA), which is one of the quercetin metabolites in the blood after an intake of quercetin-rich food, on the production of hydrogen peroxide (H2O2)-induced intracellular reactive oxygen species in mouse fibroblast 3T3 cultured cells. When the cells were exposed to H2O2 in the presence of quercetin or Q3GA, Q3GA was found to be less effective than quercetin. In the case of a pretreatment with quercetin or Q3GA before the exposure, Q3GA, but not the quercetin aglycon, exerted an inhibitory effect, although its cellular uptake was unlikely. The quercetin aglycon appeared to fail in its antioxidative effect due to metabolic conversion into isorhamnetin conjugates, with substantial oxidative degradation resulting from the pretreatment. It is, therefore, suggested that quercetin metabolites take part in the protection of intracellular oxidative stress induced by the extraneous attack of H2O2.
Keiko Azuma, Katsunari Ippoushi, Hidekazu Ito, Hisao Higashio and Junji Terao : Combination of lipids and emulsifiers enhances the absorption of orally administered quercetin in rats, Journal of Agricultural and Food Chemistry, Vol.50, No.6, 1706-1712, 2002.
(Summary)
The effects of lipids, emulsifiers, and ethanol on the absorption of orally administered quercetin in rats were investigated for its efficient intestinal absorption. Rats were administered 150 micromol/kg quercetin in water supplemented with lipids and/or emulsifiers, or ethanol, and blood was collected from the tail for 6 h after administration. Co-administration of lipids such as lecithin and soybean oil or emulsifiers including sucrose fatty acid ester, polyglycerol fatty acid ester, and sodium taurocholate had no statistically significant effects on quercetin absorption, although these constituents rather increased the accumulation of conjugated forms of quercetin and those of isorhamnetin in rat plasma. However, the combination of lipids and emulsifiers enhanced the absorption of quercetin significantly. Thirty and fifty percent (v/v) of the ethanol in the vehicle raised the efficiency of quercetin absorption in a concentration-dependent manner. Quercetin absorption-enhancing effects of these constituents seemed to be affected by quercetin's solubility in respective vehicles used for the administration. Ethanol is not helpful for the effective absorption of quercetin, as a high concentration is required. In conclusion, a combination of lipids and emulsifiers is necessary for enhancing quercetin absorption.
Begum Nahar Aynun and Junji Terao : Protective Effect of α-Tocotrienol against Free Radical-Induced Impairment of Erythrocyte Deformability, Bioscience, Biotechnology, and Biochemistry, Vol.66, No.2, 398-403, 2002.
(Summary)
α-Tocotrienol (α-T3) has been suggested to protect cellular membranes against free radical damage. This study was done to estimate the effect of α-T3 on free radical-induced impairment of erythrocyte deformability by comparing it to α-tocopherol (α-T). An erythrocyte suspension containing 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) was forced to flow through microchannels with an equivalent diameter of 7 μm for measuring erythrocyte deformability. A higher concentration of AAPH caused a marked decrease in erythrocyte deformability with concomitant increase of membranous lipid peroxidation. Treatment of erythrocytes with α-T or α-T3 suppressed the impairment of erythrocyte deformability as well as membranous lipid peroxidation and they also increased erythrocyte deformability even in the absence of AAPH. In these cases, the protecting effect of α-T3 was significantly higher than that of α-T. We emphasize that higher incorporating activity of α-T3 into erythrocyte membranes seems to be the most important reason for higher protection against erythrocyte oxidation and impairment its deformability.
Naomi Osakabe, Akiko Yasuda, Midori Natsume, Toshio Takizawa, Junji Terao and Toshio Takizawa : Catechins and Their Oligomers Linked by C4→C8 Bonds Are Major Cacao Polyphenols and Protect Low-Density Lipoprotein from Oxidation In Vitro, Experimental Biology and Medicine, Vol.227, No.1, 51-56, 2002.
(Summary)
In vitro effects of catechins and their oligomers linked by C4 --> C8 bonds are major antioxidative components of chocolate and cocoa. Their effects on the susceptibility of human low-density lipoprotein (LDL) to oxidation were evaluated. The strength of the antioxidative activity was measured using copper ions as the radical generator as compared by weight varied in the following order: (+)-catechin > procyanidin B2 > or = (-)-epicatechin > or = procyanidin C1 > cinnamtannin A2. Using 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) (MeO-AMVN) as the radical generator, the order was (-)-epicatechin > or = procyanidin B2 > or = procyanidin C1 > (+)-catechin > or = cinnamtannin A2. It is suggested that these compounds contribute to the activity of cacao products to protect LDL from oxidation.
Junji Terao, Mariko Miyoshi and Sayuri Miyamoto : Thin-layer chromatography blotting for the fluorescence detection of phospholipid hydroperoxides and cholesteryl ester hydroperoxides, Journal of Chromatography. B, Biomedical Sciences and Applications, Vol.765, No.2, 199-203, 2001.
(Summary)
A blotting technique was developed to specifically detect lipid hydroperoxides in thin-layer chromatography. Phosphatidylcholine hydroperoxides and cholesteryl linoleate hydroperoxides ranging from 0.1 to 0.5 nmol, which were prepared by reaction with soybean lipoxygenase, were visualized as fluorescent spots on the blotted membrane by immersing the plate into a blotting solvent containing 0.01% (w/v) diphenyl-1-pyrenylphosphine. This technique was applied successfully to monitor lipid peroxidation in human low-density lipoprotein in vitro.
Seigo Baba, Naomi Osakabe, Midori Natsume, Yuko Muto, Toshio Takizawa and Junji Terao : Absorption and Urinary Excretion of (-)-Epicatechin after Administration of Different Levels of Cocoa Powder or (-)-Epicatechin in Rats, Journal of Agricultural and Food Chemistry, Vol.49, No.12, 6050-6056, 2001.
(Summary)
(-)-Epicatechin is a major polyphenol component of cocoa powder. The absorption and urinary excretion of (-)-epicatechin following administration of different levels of either cocoa powder (150, 750, and 1500 mg/kg) or (-)-epicatechin (1, 5, and 10 mg/kg) were evaluated in rats. Both the sum of plasma (-)-epicatechin metabolites at 1 h postadministration and peak plasma concentrations increased in a dose-dependent fashion. The sum of (-)-epicatechin metabolites in urine, excreted within 18 h postadministration, also increased with dose. Moreover, the sum of (-)-epicatechin metabolites excreted in urine reached the same level in both (-)-epicatechin and cocoa powder administration groups for equivalent amounts of (-)-epicatechin. These results suggest that, in the dose range examined in this study, bioavailability of (-)-epicatechin following administration of either (-)-epicatechin or cocoa powder shows dose dependence and that the various compounds present in cocoa powder have little effect on the bioavailability of (-)-epicatechin in cocoa powder.
(Keyword)
(-)-Epicatechin / cocoa powder / absorption / excretion / rat
Junji Terao, Sachiyo Yamaguchi, Mutsuko Shirai, Mariko Miyoshi, JH Moon, Syunji Oshima, Takahiro Inakuma, Tojiro Tsushida and Yoji Kato : Protection by quercetin and quercetin 3-O-beta-D-glucuronide of peroxynitrite-induced antioxidant consumption in human plasma low-density lipoprotein, Free Radical Research, Vol.35, No.6, 925-931, 2001.
(Summary)
Effect of quercetin and its conjugated metabolite quercetin 3-O-beta-D-glucuronide (Q3GA), on peroxynitrite-induced consumption of lipophilic antioxidants in human plasma low-density lipoprotein (LDL) was measured to estimate the role of dietary flavonoids in the defense system against oxidative modification of LDL based on the reaction of nitric oxide and superoxide anion. Synthesized peroxynitrite-induced consumption of endogenous lycopene beta-carotene and alpha-tocopherol was effectively suppressed by adding quercetin aglycone into LDL solution. Q3GA also inhibited the consumption of these antioxidants effectively. These results indicate that dietary quercetin is capable of inhibiting peroxynitrite-induced oxidative modification of LDL in association with lipophilic antioxidants present within this lipoprotein particle.
Mutsuko Shirai, Jae-Hak Moon, Tojiro Tsushida and Junji Terao : Inhibitory effect of a quercetin metabolite, quercetin 3-O-beta-D-glucuronide, on lipid peroxidation in liposomal membranes, Journal of Agricultural and Food Chemistry, Vol.49, No.11, 5602-5608, 2001.
(Summary)
To study the antioxidant activity of quercetin 3-O-beta-D-glucuronide (Q3GA), which is one of the quercetin metabolites in the blood after intake of quercetin-rich food, the inhibitory effect of Q3GA on lipid peroxidation was estimated using phosphatidylcholine large unilamellar vesicles (PC LUV) as a biomembrane model. Iron ion, an aqueous peroxyl radical generator, a peroxynitrite generator, or lipoxygenase was used as the inducer of lipid peroxidation. In all cases, Q3GA inhibited lipid peroxidation significantly, although its inhibitory effect was lower than that of quercetin aglycon. The ultrafiltration of PC LUV containing Q3GA revealed that Q3GA has low but significant affinity with the membranes of phospholipid bilayers. It is therefore likely that Q3GA acts as an efficient antioxidant in membranous lipid peroxidation through its localization in the phospholipid bilayer. This conjugated quercetin metabolite seems to retain the ability to protect cellular and subcellular membranes from peroxidative attack by reactive oxygen species and peroxidative enzymes.
Tatsuhiro Uchida, Masatake Imai, Gorou Kuwata, Junji Terao, Nana Yoshida, Naohiro Gotoh and Shun Wada : Antioxidant Axtibity of Phytic Acid and its Hydrolysis Products for Marine Lipid, Nippon Shokuhin Kagaku Kogaku Kaishi, Vol.48, No.10, 726-732, 2001.
(Summary)
The antioxidant effects of phytic acid (inositol hexaphosphate: IP6) were compared with its hydrolysis products (inositol diphosphate: IP2-inositol pentaphosphate: IP5). The antioxidant activity and chelating activity of metal ion of IP6 and IP2-IP5 (IPns) were examined by using the evaluation of ferric thiocyanate (FTC), β-carotene bleaching, 2, 2-diphenyl-l-picrylhydrazyl (DPPH) radical scavenging, and tetramethylmurexide inhibiting methods. (1) Result of the FTC and β-carotene bleaching methods indicated that the most effective antioxidant was the IP6 and its antioxidant activity was similar to the activity of α-tocopherol. (2) Chelating activities of IPns for Fe<SUP>2+</SUP>and Cu<SUP>2+</SUP> were showed that IP6 has the most strong chelating activity. In proportionately, as the number of phosphate group increases in IPns, the chelating activities are strong. (3) IPns inhibited the marine oil oxidation with Fe<SUP>2+</SUP> and that has the strong synergistic effects with α-tocopherol. The inhibition of marine lipid oxidation and the synergistic effects with α-tocopherol followed the order: IP6>IP5>IP4>IP3>IP2.
Dacaranhe Dique Clemente and Junji Terao : A unique antioxidant activity of phosphatidylserine on iron-induced lipid peroxidation of phospholipid bilayers, Lipids, Vol.36, No.10, 1105-1110, 2001.
(Summary)
The relationship between the antioxidant effect of acidic phospholipids, phosphatidic acid (PA), phosphatidylglycerol (PG) and phosphatidylserine (PS), on iron-induced lipid peroxidation of phospholipid bilayers and their abilities to bind iron ion was examined in egg yolk phosphatidylcholine large unilamellar vesicles (EYPC LUV). The effect of each acidic phospholipid added to the vesicles at 10 mol% was assessed by measuring phosphatidylcholine hydroperoxides (PC-OOH) and thiobarbituric acid-reactive substances. The addition of dipalmitoyl PS (DPPS) showed a significant inhibitory effect, although the other two acidic phospholipids, dipalmitoyl PA (DPPA) and dipalmitoyl PG (DPPG), did not exert the inhibition. Neither dipalmitoyl PC (DPPC) nor dipalmitoyl phophatidylethanolamine (DPPE) showed any remarkable inhibition on this system. None of the tested phospholipids affected the lipid peroxidation rate remarkably when the vesicles were exposed to a water-soluble radical generator. The iron-binding ability of each phospholipid was estimated on the basis of the amounts of iron recovered in the chloroform/methanol phase after separation of the vesicle solution to water/methanol and chloroform/methanol phases. EYPC LUV containing DPPS, DPPA, and DPPG had higher amounts of bound iron than those containing DPPC and DPPE, indicating that these three acidic phospholipids possess an iron-binding ability at a similar level. Nevertheless, only DPPS suppressed iron-dependent decomposition of PC-OOH significantly. Therefore, it is likely that these three acidic phospholipids possess a significant iron-binding ability, although this ability per se does not warrant them antioxidative activities. The ability to suppress the iron-dependent decomposition of PC-OOH may explain the unique antioxidant activity of PS.
Jae-Hak Moon, Tojiro Tsushida, Kazuhiko Nakahara and Junji Terao : Identification of quercetin 3-O-beta-D-glucuronide as an antioxidative metabolite in rat plasma after oral administration of quercetin, Free Radical Biology and Medicine, Vol.30, No.11, 1274-1285, 2001.
(Summary)
The potential beneficial effect of dietary quercetin (3,3',4',5,7-pentahydroxyflavone) has attracted much attention in relation to the prevention of cardiovascular disease. It is generally recognized that dietary quercetin is subject to metabolic conversion resulting in conjugated forms during absorption and circulation. However, no quercetin conjugates have yet been identified from biological fluids or tissues. In the present study, we isolated and characterized two quercetin conjugates from the plasma of quercetin-administered rats. The blood plasma was collected from 26 rats 30 min after oral administration of quercetin (250 mg/kg body weight), concentrated, dissolved in 2% acetic acid aqueous solution (pH 2.65), and extracted with ethyl acetate. Two compounds (P2, P3) were obtained from the extract by repeated reversed-phase HPLC. On the other hand, two quercetin glucuronides were synthesized chemically and identified as quercetin 3-O-beta-D-glucuronide (Q3GA) and quercetin 4'-O-beta-D-glucuronide (Q4'GA), as determined from FABMS, 1H- and 13C-NMR, and HMBC data. The retention times of P2 and P3 in the HPLC chromatogram corresponded to those of Q3GA and Q4'GA, respectively. FABMS data demonstrated that P2 and P3 are quercetin monoglucuronides. 1H-NMR data for P2 were completely in agreement with those for Q3GA. P2 was therefore identified as Q3GA. This is, to our knowledge, the first evidence that Q3GA accumulates in vivo after oral administration of quercetin. Q3GA is likely to act as an effective antioxidant in blood plasma low-density lipoprotein, because this conjugated metabolite was found to possess a substantial antioxidant effect on copper ion-induced oxidation of human plasma low-density lipoprotein as well as 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity.
C.D. Dacaranhe and Junji Terao : Effect of Phosphatidic Acid and Phosphatidylserine on Lipid Oxidation in Beef Homogenate During Storage and in Emulsified Sardine Oil, Journal of Food Science, Vol.66, No.3, 422-427, 2001.
Yuka Aoyama, Ayaka Tokuno, Junji Terao, Nobuji Nakatani and Yoko Takei : Various cooking methods and the flavonoid content in onion, Journal of Nutritional Science and Vitaminology, Vol.47, No.1, 78-83, 2001.
(Summary)
Onion is a major source of flavonoids and is cooked in various ways in the world. The major flavonoids in onion are two quercetin glycosides, quercetin 4'-O-β-gluco-side (Q4'G) and quercetin 3, 4'-Oβ-diglucosides (Q3, 4'G), which are recognized as bioac-tive substances that are good for our health. We have investigated the effect of cooking pro-cedures on the content of antioxidants. We selected quercetin conjugates, total phenol com-pounds, and ascorbic acid to estimate the amount of flavonoid ingestion from onion. We ex-amined the following cooking methods; boiling, frying with oil and butter, and microwave cooking. Various cooking methods do not consider the degradation of quercetin conjugates when cooking onion. Microwave cooking without water better retains flavonoids and ascor-bic acid. Frying does not affect flavonoid intake. The boiling of onion leads to about 30% loss of quercetin glycosides, which transfers to the boiling water. At that time, the effect of addi-tives on the quercetin conjugates is different according to the compounds. The hydrolysis of quercetin glycosides for daily cooking might occur with the addition of seasonings such as glutamic acid. Additional ferrous ions accelerated the loss of flavonoids.
Seon-Jae Kim, Eiichi Nara, Hidetaka Kobayashi, Junji Terao and Akihiko Nagao : Formation of cleavage products by autoxidation of lycopene, Lipids, Vol.36, No.2, 191-199, 2001.
(Summary)
The cleavage products formed by autoxidation of lycopene were evaluated in order to elucidate possible oxidation products of lycopene in biological tissues. Lycopene solubilized at 50 microM in toluene, aqueous Tween 40, or liposomal suspension was oxidized by incubating at 37 degrees C for 72 h. Among a number of oxidation products formed, eight products in the carbonyl compound fraction were identified as 3,7,11 -trimethyl-2,4,6,10-dodecatetraen-1-al, 6,10,14-trimethyl-3,5,7,9,13-pentadecapentaen-2-one, acycloretinal, apo-14'-lycopenal, apo-12'-lycopenal, apo-10'-lycopenal, apo-8'-lycopenal, and apo-6'-lycopenal. These correspond to a series of products formed by cleavage in the respective 11 conjugated double bonds of lycopene. The maximal formation of acycloretinal was 135 nM in toluene, 49 nM in aqueous Tween 40, and 64 nM in liposomal suspension. Acycloretinoic acid was also formed by autoxidation of lycopene, although its formation was lower in the aqueous media than in toluene. The pig liver homogenate had the ability to convert acycloretinal to acycloretinoic acid, comparable to the conversion of all-transretinal to all-trans-retinoic acid. These results suggest that lycopene might be cleaved to a series of apolycopenals and short-chain carbonyl compounds under the oxidative conditions in biological tissues and that acycloretinal is further enzymatically converted to acycloretinoic acid.
Miki Hiemori, Noriko Bando, Tadashi Ogawa, Hisao Shimada, Hideaki Tsuji, Rintaro Yamanishi and Junji Terao : Occurrence of IgE antibody-recognizing N-linked glycan moiety of a soybean allergen, Gly m Bd 28K, International Archives of Allergy and Immunology, Vol.122, No.4, 238-245, 2000.
(Summary)
It has been reported that N-linked glycan moieties of glycoproteins function as IgE-reactive determinants. Gly m Bd 28K, a soybean allergen, was a glycoprotein with glycan moieties, which are supposed to be the Man(3)GlcNAc(2) backbone with the beta1-->2 xylose and alpha1-->3 fucose branches. The purpose of the present study was to examine the IgE-binding ability of the glycan moiety of Gly m Bd 28K in the binding reaction with patients' sera. A peptide containing the glycan moiety was prepared from Gly m Bd 28K by digestion with lysyl endopeptidase. The binding site of the glycan moiety was determined by amino acid sequence analyses. The glycan moiety of the allergen was characterized using anti-horseradish peroxidase antibody (anti-HRP) recognizing the N-linked glycan moieties of glycoproteins. The binding of patients' IgE antibodies with their glycan moiety was examined by an immunostaining technique using the glycopeptide and its deglycosylated peptide derived from Gly m Bd 28K. The binding site of the glycan moiety in Gly m Bd 28K was shown to be its Asn20 residue. Gly m Bd 28K did react with anti-HRP and the sera of soybean-sensitive patients, but the binding of IgE antibodies was inhibited by the preincubation with anti-HRP. Moreover, the glycopeptide also reacted with the sera of soybean-sensitive patients, but its deglycosylated peptide did not react with any IgE antibodies of patients' sera. The specific IgE antibodies recognizing the N-linked glycan moieties of Gly m Bd 28K and other glycoproteins with homologous glycan moieties occur in the sera of soybean-sensitive patients. It was indicated that the N-linked glycan moieties such as that of Gly m Bd 28K may be one of the common IgE-reactive determinants distributed in various plant food proteins.
Kenji Fukuzawa, Yasuki Inokami, Akira Tokumura, Junji Terao and Asahi Suzuki : Rate constants for quenching singlet oxygen and activities for inhibiting lipid peroxidation of carotenoids and alpha-tocopherol in liposomes, Lipids, Vol.33, No.8, 751-756, 1998.
(Summary)
The (1)O2 quenching rate constants (kQ) of alpha-tocopherol (alpha-Toc) and carotenoids such as beta-carotene, astaxanthin, canthaxanthin, and lycopene in liposomes were determined in light of the localization of their active sites in membranes and the micropolarity of the membrane regions, and compared with those in ethanol solution. The activities of alpha-Toc and carotenoids in inhibiting (1)O2-dependent lipid peroxidation (reciprocal of the concentration required for 50% inhibition of lipid peroxidation: [IC50](-1)) were also measured in liposomes and ethanol solution and compared with their kQ values. The kQ and [IC50](-1) values were also compared in two photosensitizing systems containing Rose bengal (RB) and pyrenedodecanoic acid (PDA), respectively, which generate (1)O2 at different sites in membranes. The kQ values of alpha-Toc were 2.9 x 10(8) M(-1) s(-1) in ethanol solution and 1.4 x 10(7) M(-1) s(-1) (RB system) or 2.5 x 10(6) M(-1) s(-1) (PDA system) in liposomes. The relative [IC50](-1) value of alpha-Toc in liposomes was also five times higher in the RB system than in the PDA-system. In consideration of the local concentration of the OH-group of alpha-Toc in membranes, the kQ value of alpha-Toc in liposomes was recalculated as 3.3 x 10(6) M(-1) s(-1) in both the RB and PDA systems. The kQ values of all the carotenoids tested in two photosensitizing systems were almost the same. The kQ value of alpha-Toc in liposomes was 88 times less than in ethanol solution, but those of carotenoids in liposomes were 600-1200 times less than those in ethanol solution. The [IC50](-1) value of alpha-Toc in liposomes was 19 times less than that in ethanol solution, whereas those of carotenoids in liposomes were 60-170 times less those in ethanol solution. There were no great differences (less than twice) in the kQ and [IC50](-1) values of any carotenoids. The kQ values of all carotenoids were 40-80 times higher than that of alpha-Toc in ethanol solution but only six times higher that of alpha-Toc in liposomes. The [IC50](-1) values of carotenoid were also higher than that of alpha-Toc in ethanol solution than in liposomes, and these correlated well with the kQ values.
Kenji Fukuzawa, Yasuki Inokami, Akira Tokumura, Junji Terao and Asahi Suzuki : Singlet oxygen scavenging by lpha-tocopherol and eta-carotene: Kinetic studies in phospholipid membranes and ethanol solution, BioFactors, Vol.7, No.1-2, 31-40, 1998.
(Summary)
The rate constants (ks) of 1O2 scavenging for alpha-tocopherol (alpha-Toc) and beta-carotene (beta-Car) were measured in liposome membranes, and compared with those in EtOH solution. 1O2 was site-specifically generated by photoirradiation using two photosensitizers, water-soluble Rose bengal (RB) and lipid-soluble 12-(1-pyrene)-dodecanoic acid (PDA). The ks value for beta-Car in EtOH solution was 1.3 x 10(10) M-1 s-1, which was 36 times that for alpha-Toc (3.6 x 10(8) M-1 s-1), but there was no difference between their ks values in liposomes (1.8 x 10(7) M-1 s-1 for beta-Car and 1.2 x 10(7) M-1 s-1 for alpha-Toc). In the liposomes, the ks value for alpha-Toc was affected by the membrane site where 1O2 was generated, which depended on the localization of the photosensitizer, being high at the membrane surface in the RB-system and low in the inner region of the membrane in the PDA-system. In contrast, the ks value for beta-Car was not affected by the 1O2-generating site. These differences were supposed to be caused by differences in the relative concentrations of 1O2 and active sites of alpha-Toc and beta-Car in the membranes. alpha-Toc and beta-Car inhibited 1O2-dependent peroxidation of egg yolk phosphatidylcholine (egg PC). The concentrations of alpha-Toc required for 50% inhibition of lipid peroxidation (IC50) were higher than those of beta-Car, being more than 6 times higher in EtOH solution and less than 2 times higher in liposomes. The ratio of the antioxidant activity of beta-Car to that of alpha-Toc was more in EtOH solution than in liposomes, and was well correlated with the ratio of their 1O2 scavenging rate constants.
Kenji Fukuzawa, Kayo Matsuura, Akira Tokumura, Asahi Suzuki and Junji Terao : Kinetics and Dynamics of Singlet Oxygen Scavenging by -Tocopherol in Phospholipid Model Membranes, Free Radical Biology and Medicine, Vol.22, No.5, 923-930, 1997.
(Summary)
Scavenging of singlet oxygen (1O2) by alpha-tocopherol (alpha-Toc) was investigated in liposomes. 1O2 was generated by photoirradiation in the presence of two photosensitizers, water-soluble methylene blue (MB) and lipid-soluble 12-(1-pyrene)dodecanoic acid (PDA). The rates of oxidation of alpha-Toc differed depending on the photosensitizing dye and the membrane charge: in the MB-system, alpha-Toc was oxidized fast in negatively charged dimyristoylphosphatidylcholine (DMPC) liposomes containing dicetylphosphate (DCP) and slowly in neutrally charged DMPC liposomes and positively charged DMPC liposomes containing stearylamine (SA), but in the PDA-system, the oxidation rate was independent of the membrane charge. The charge-dependent difference in the MB-system would be due to the site of 1O2 generation depending on the charge-dependent distribution of MB, because positively charged MB increased the zeta-potential of DCP-DMPC liposomes by its interaction with DCP at the membrane surface, but changed the zeta-potentials of DMPC and SA-DMPC liposomes less because of its location in the bulk water phase. The oxidation rate of alpha-Toc in liposomes was different from that in EtOH solution: in the MB system, the oxidation rate was faster in EtOH solution than in DMPC or SA-DMPC liposomes but the same as that in DCP-DMPC liposomes. However, in the PDA system, the oxidation rate was slower in EtOH solution than in DMPC liposomes with or without a charge. Membrane fluidity changed the rate of alpha-Toc oxidation in liposomes, the rate being higher in the liquid crystalline phase than the gel phase, as judged by the higher rate in DMPC liposomes than in dipalmitoylphosphatidylcholine (DPPC) liposomes at 30 degrees C. The rate constants of alpha-Toc for scavenging, the chemical reaction and physical quenching of 1O2 were determined in membranes using DCP-DMPC liposomes labeled with 1,3-diphenyl-isobenzofuran (DPBF), which traps 1O2. These constants differed in the two photosensitizing systems, being higher in the MB-system than in the PDA-system, and were lower than those in EtOH solution.
(Keyword)
electrochemistry / Ethanol / Free Radical Scavengers / Free Radicals / In Vitro Techniques / Kinetics / Lauric Acids / liposomes / Membrane Fluidity / Methylene Blue / oxidation and reduction / Oxygen / Phosphatidylcholines / Photosensitizing Agents / Singlet Oxygen / Solutions / vitamin E
Junji Terao : Development of singlet oxygen absorption capacity (SOAC) assay method. 3. Measurements of the SOAC values for phenolic antioxidants., Journal of Agricultural and Food Chemistry, Vol.60, No.32, 7905-7916, 2012.
(Summary)
Measurements of the singlet oxygen ((1)O(2)) quenching rates (k(Q) (S)) and the relative singlet oxygen absortpion capacity (SOAC) values were performed for 16 phenolic antioxidants (tocopherol derivatives, ubiquinol-10, caffeic acids, and catechins) and vitamin C in ethanol/chloroform/D(2)O (50:50:1, v/v/v) solution at 35 °C. It has been clarified that the SOAC method is useful to evaluate the (1)O(2)-quenching activity of lipophilic and hydrophilic antioxidants having 5 orders of magnitude different rate constants from 1.38 × 10(10) M(-1) s(-1) for lycopene to 2.71 × 10(5) for ferulic acid. The logarithms of the k(Q) (S) and the SOAC values for phenolic antioxidants were found to correlate well with their peak oxidation potentials (E(p)); the antioxidants that have smaller E(p) values show higher reactivities. In previous works, measurements of the k(Q) (S) values for many phenolic antioxidants were performed in ethanol. Consequently, measurements of the k(Q) (S) and relative SOAC values were performed for eight carotenoids in ethanol to investigate the effect of solvent on the (1)O(2)-quenching rate. The k(Q) (S) values for phenolic antioxidants and carotenoids in ethanol were found to correlate linearly with the k(Q) (S) values in ethanol/chloroform/D(2)O solution with a gradient of 1.79, except for two catechins. As the relative rate constants (k(Q)(AO) (S)/k(Q)(α-Toc) (S)) of antioxidants (AO) are equal to the relative SOAC values, the SOAC values do not depend on the kinds of solvent used, if α-tocopherol is used as a standard compound. In fact, the SOAC values obtained for carotenoids in mixed solvent agreed well with the corresponding ones in ethanol.
Akari Ishisaka, Satomi Ichikawa, Hiroyuki Sakakibara, K Mariusz Piskula, Toshiyuki Nakamura, Yoji Kato, Mikiko Ito, Ken-ichi Miyamoto, Akira Tsuji, Yoshichika Kawai and Junji Terao : Accumulation of orally administered quercetin in brain tissue and its antioxidative effects in rats., Free Radical Biology and Medicine, Vol.51, No.7, 1329-1336, 2011.
(Summary)
Quercetin is widely distributed in vegetables and herbs and has been suggested to act as a neuroprotective agent. Here, we demonstrate that quercetin can accumulate enough to exert biological activity in rat brain tissues. Homogenates of perfused rat brain without detectable hemoglobin contaminants were treated with -glucuronidase/sulfatase and the released quercetin and its methylated form were analyzed using high-performance liquid chromatography (HPLC) with three different detection methods. Both quercetin and the methylated form were detected in the brain of quercetin-administered rats using HPLC-UV and HPLC with electrochemical detection and were further identified using HPLC-tandem mass spectrometry. Oral administration of quercetin (50mg/kg body wt) attenuated the increased oxidative stress in the hippocampus and striatum of rats exposed to chronic forced swimming. The possible transport of quercetin derivatives into the brain tissue was reproduced in vitro by using a rat brain capillary endothelial cell line, a model of the blood-brain barrier. These results show that quercetin could be a potent nutrient that can access the brain and protect it from disorders associated with oxidative stress.
榊原 啓之 and Junji Terao : screeing of antidepressant-like food factors and herbal medicines, Foods and food Ingredients journal of Japan, Vol.211, No.8, 720-726, 2006.
Noriko Bando, MASAMI YAMAMOTO, Rintaro Yamanishi and Junji Terao : Synergistic Effect of Vitamin E and ß-Carotene on the Suppression of Ovalbumin-Specific Immunoglobulin E Production in Mice, Annals of the New York Academy of Sciences, Vol.1031, No.0, 415-417, 2004.
(Keyword)
immunoglobulin E (IgE) antibody / vitamin E / ß-carotene / type I allergy
Junji Terao, C Kamada, M Kameyama, J-H Moon and E.L. Silva da : Antioxidative Effect of Dietary Flavonoid Quercetin in Rabbit Aorta, Biennial Meeting of the Society for Free Radical Research International SFRR, 49-54, 2004.
6.
Masako Yamamoto and Junji Terao : Effect of dietary oil and tea catechins on the peroxidizability of rat plasma and large intestinal mucosa, Research bulletin of Tokushima Bunri University, Vol.0, No.67, 135-144, 2004.
Junji Terao, M Shirai, Moon J-H, Kaeko Murota and Rintaro Yamanishi : Antioxidant Effect of a Conjugated Quercetin Metabolite on Cultured Cells, XI Biennial Meeting of the Society for Free Radical Research International, 633-636, 2002.
9.
Junji Terao : Methods to Quantify Antioxidant Activity of Tea and Tea Extracts In Vitro, Food Science and Nutrition, Vol.41, No.5, 408, 2001.
10.
Junji Terao and Takashi Nagai : Chapter 14 Effect of Lipase Hydrolysis on Lipid Peroxidation in Fish Oil Emulsion, Omega-3 Fatty Acids Chemistry, Nutrition, and Health Effects, 176-190, 2001.
Junji Terao and Rie Mukai : Prenylation modulates the bioavailability and bioaccumulation of dietary flavonoids., Archives of Biochemistry and Biophysics, Vol.559, 12-16, Apr. 2014.
(Summary)
Prenylflavonoids are distributed widely in the plant kingdom and have attracted appreciable attention because of their potential benefits for human health. Prenylation may be a promising tool for applying the biological functions of flavonoids to clinical uses. The bioavailability and bioaccumulation of prenylflavonoids have not been clarified, but extensive studies have been accomplished on their biological functions. This review provides current knowledge on the bioavailability of prenylflavonoids, including their absorption and metabolism in the intestine, as well as their bioaccumulation in specific tissues. Despite higher uptake into epithelial cells of the digestive tract, the bioavailability of single-dose prenylflavonoids seems to be lower than that of the parent flavonoids. Efflux from epithelial cells to the blood circulation is likely to be restricted by prenyl groups, resulting in insufficient increase in the plasma concentration. Rodent studies have revealed that prenylation enhances accumulation of naringenin in muscle tissue after long-term feeding; and that prenylation accelerates accumulation of quercetin in liver tissue. Efflux from hepatocytes to blood and enterohepatic circulations may be restricted by prenyl groups, thereby promoting slow excretion of prenylflavonoids from the blood circulation and efficient uptake to tissues. The hepatotoxicity and other deleterious effects, taken together with beneficial effects, should be considered because unexpectedly high accumulation may occur in some tissues after long-term supplementation.
Rie Mukai and Junji Terao : Role of dietary flavonoids in oxidative stress and prevention of muscle atrophy, The Journal of Physical Fitness and Sports Medicine, Vol.2, No.4, 385-392, Nov. 2013.
(Summary)
Functional foods for the prevention of disuse muscle atrophy (DMA) are expected to improve the quality of life (QoL) of bedridden people. Ubiquitin ligases targeting muscle protein degradation, atrogin-1 and muscle-specific ring finger protein (MuRF-1), are critical in the degradation of muscle protein, and oxidative stress induced by mitochondrial dysfunction seems to be involved in muscle atrophy. Dietary antioxidants that attenuate the oxidative stress in skeletal muscle are strong candidates as food ingredients for preventing DMA. The antioxidative flavonoid quercetin was found to prevent DMA by attenuating the induction of atrogin-1/MuRF-1 in mice undertaking the tail suspension test. Several studies revealed that dietary quercetin accumulates in skeletal muscle after metabolic conjugation during absorption. There are many arguments that antioxidant activity is essential for dietary flavonoids to exert their preventive effects, but modulation of the IGF-1 signaling pathway is definitively involved in the mechanism of prevention. Nevertheless, dietary flavonoids (including quercetin) may be potential food factors in the prevention of muscle atrophy. Dietary flavonoids are expected to prevent DMA by attenuating oxidative stress derived from mitochondrial dysfunction.
Shin Nishiumi, Shingo Miyamoto, Kyuichi Kawabata, Kohta Ohnishi, Rie Mukai, Akira Murakami, Hitoshi Ashida and Junji Terao : Dietary flavonoids as cancer-preventive and therapeutic biofactors., Frontiers in Bioscience (Scholar edition), Vol.3, 1332-1362, Jun. 2011.
(Summary)
Flavonoids are present in many plants, and hence, in foods and ingredients derived from them. These polyphenolic compounds have attracted renewed attention as potential anticarcinogens, and the molecular mechanisms of their anticarcinogenic effects and their bioavailability have been extensively explored. In this review, we focus on the major dietary flavonoids; flavones, flavonols, and flavan-3-ols (catechins), and evaluate their roles in cancer prevention. After absorption with or without metabolic conjugation, flavonoids are transported to target organs where they exert their anticarcinogenic activity. The molecular mechanisms of the anticarcinogenic effects of flavonoids include their antagonistic effect on the aryl hydrocarbon receptor (AhR), and regulation of phase I and II drug metabolizing enzymes and phase III transporters. Experimental evidence suggests that flavonoids modulate signal transduction pathways at each stage of carcinogenesis. The interactions between flavonoids and biomolecules in vivo must be investigated in detail to identify specific targets. In addition, the potential side effects should be considered when flavonoid supplements are used for cancer prevention. Therefore, the use of flavonoids as chemopreventive agents should be further investigated to establish safe levels of flavonoid intake.
室田 佳恵子, Yoshichika Kawai and Junji Terao : Transport Mechanism of Dietary Flavonoids and their Metabolites, Vitamins, Vol.84, No.12, 589-598, Dec. 2010.
(Summary)
Flavonoids are present in various plant foods such as vegetables, fruits and beverages. Flavonoids are known as powerful antioxidants and have attracted much attention to their potential role in the prevention of various diseases. In plant foods, most flavonoids exist as glycosides and/or acidic forms, and the type of a sugar moiety is a major determinant of the intestinal absorption. In the gastrointestinal tract, dietary flavonoids are mainly absorbed as their aglycone forms by simple diffusion, whereas there are some kind of membrane transporters that may work for cellular influx of certain flavonoids. The predominant circulating molecules after an oral consumption are conjugative metabolites because flavonoids undergo extensive intestinal and hepatic glucuronidation and sulfation. ABC transporters have been shown to serve for the cellular efflux of flavonoid metabolites. This review will summarize the current literatures regarding on the transport mechanism of dietary flavonoids and their conjugative metabolites.
Junji Terao : Occurrence of lipid peroxidation and its elimination in biological systems, Journal of Analytical Bio-Science, Vol.32, No.4, 257-264, Sep. 2009.
Junji Terao, Yoshichika Kawai and Kaeko Murota : Development in physiological function of polyphenols, Journal of Clinical and Experimental Medicine, 208-211, Oct. 2006.
Junji Terao : 基礎栄養 食品抗酸化成分の最近の話題 (1)ビタミンEの機能はどこまでわかったか?, The Japanese Journal of Clinical Nutrition, Vol.106, No.1, 13, Jan. 2005.
27.
Seigo Baba and Junji Terao : Role of Metabolism in Physillogical Function of Polyphenol Catechins, Oleoscience, Vol.4, No.7, 271-277, Jul. 2004.
(Summary)
Polyphenols present in plant foods and beverages have attracted much attention as food factors in the prevention of life style-related diseases and health promotion. Here we presented recent studies on the bioavailability of polyphenols, in particular, the relationship between the absorption/metabolism of catechins and their physiological functions including antioxidative effect. In either rats or humans, both (+) -catechin and (-) -epicatechin were found to be more absorptive than gallate-binding catechins. In plasma, they are present mainly as conjugated metabolites, namely glucuronides, sulfates and their methylated products. Nevertheless, their metabolite profiles are different between rats and humans. For example, considerable amounts of sulfates accumulate in human plasma. Catechin metabolites still possess antioxidative effect as long as catechol structure is unchanged. Alternatively, catechin metabolites were recently reported to suppress the induction of apoptosis in nervous cells. Therefore, biological activity of catechin metabolites should be clarified in detail in order to estimate the physiological function of dietary catechins.
Rie Mukai, Goto-Inoue Naoko, Ukawa Yuichi, Kohara Akiko, Oe Kenichi and Junji Terao : Tissue distribution of 8-prenylnaringnein in mice, Boston, MA, USA, Oct. 2024.
2.
Rie Mukai, Hisao Nemoto and Junji Terao : Estrogenic activity of 8-renylnaringenin improve skeletal muscle regeneration from disuse muscle atrophy by activating IGF-I/PI3K/Akt pathway, ICoFF2019/ISNFF2019/ICPH2019, Kobe, Nov. 2019.
3.
Nuka Erika, Kohta Ohnishi, Junji Terao and Yoshichika Kawai : Signaling pathways of ATP and adenosine could be anti-inflammatory targets of polyphenols, 8th International Conference on Polyphenols and Health, Oct. 2017.
4.
Erika Nuka, Kohta Ohnishi, Junji Terao, Yoshichika Kawai and Toshiyuki Sakaki : Polyphenols modulate ATP-induced inflammation in macrophages, 6th International conference on Food Factors (ICoFF2015), Nov. 2015.
5.
Kenji Kurokawa, Erika Nuka, Kohta Ohnishi, Shin-ichi Ikushiro, Toshiyuki Sakaki, Zai-Si Ji, Hiroshi Tsuboi, Junji Terao and Yoshichika Kawai : Anti-inflammatory activity of quercetin and the conjugates at human plasma levels, 6th International conference on Food Factors (ICoFF2015), Nov. 2015.
6.
Akari Kondo, Chiemi Kamada, Rie Mukai and Junji Terao : Effect of Quercetin and Its Metabolite on Hydrogen Peroxide-Induced Phosphorylation of Caveolin-1 in Endothelial Cells, The 6th International Conference on Food Factors: Bioconvergence for Food Function, Soul, Republic of Korea, Nov. 2015.
7.
Asami Iwanaka, Mamiko Soga, Eiichi Kotake-Nara, Akihito Nagao, Rie Mukai, Akira Takahashi and Junji Terao : Effect of Fucoxanthin and Neoxanthin on Blue Light-Emitting Diode-Irradiated Photosensitized Oxidation in Liposomal Membranes andMouse Fibroblast Cells, The 6th International Conference on Food Factors: Bioconvergence for Food Function, Soul, Republic of Korea, Nov. 2015.
8.
Hiromi Shono, Hideyuki Saito, Shinya Sato, Tomoyuki Kawamura, Hisao Nemoto, Junji Terao and Rie Mukai : A signal transduction pathway in prenylquercetin-induced heme oxygenase-1 expression in vascular endothelium cells, The 6th International Conference on Food Factors: Bioconvergence for Food Function, Soul, Republic of Korea, Nov. 2015.
9.
Rie Mukai, Onishi Asami, Fukuda Takashi, Furusawa Mutsuki, Ashitani Hiroaki, Koyama Toshiyuki, Usami-Krank Yoko and Junji Terao : Epi-catechin Gallate Selectively Accumulates in Blood Plasma after Continuous Intake of Tea Catechins in Rats and Humans, The 6th International Conference on Food Factors: Bioconvergence for Food Function, Soul, Republic of Korea, Nov. 2015.
10.
Rie Mukai, Hiromi Shono, Shinya Sato, Jeremy Spencer, Tomoyuki Kawamura, Hisao Nemoto and Junji Terao : Positional isomers of prenylquercetin differently induce hemeoxygenase-1 expression in vascular endothelial cells, 7th International Conference on Polyphenols and Health, Tours, France, Oct. 2015.
11.
Airi Otsuka, Tetsuya Shiuchi, Sachiko Chikahisa, Junji Terao and Hiroyoshi Sei : Ingestion of restrickted comfortable food improves social avoidance induced by social defeat stress, 12th Asian Congress of Nutrition, Yokohama, May 2015.
12.
Lin Yi Pei, Rie Mukai, Horikawa Hitomi and Junji Terao : 8-Prenylnaringenin enhances the recovery from disuse muscle atrophy of mice with cast immobilization, 12th Asian congress of Nutrition, Yokohama, May 2015.
13.
Rie Mukai, Naoko Matsui, Takeshi Nikawa and Junji Terao : Dietary quercetin prevents disuse muscle atrophy of denervated mice through regulation of mitochondrial biogenesis, 12th Asian congress of Nutrition, Yokohama, May 2015.
14.
Yauhen Bandaruk, Rie Mukai and Junji Terao : Role of flavonoids as possible monoamine oxidase-A regulators in the model of serotoninergic neuroblastoma SH-SY5Y cell, XXVIIth International Conference on Polyphenols &8th Tannin Conference, Nagoya, Sep. 2014.
15.
Rie Mukai, Naoko Matsui, Takeshi Nikawa and Junji Terao : Pre-intake of quercetin slow the progression of disuse muscle atrophy by mitochondrial dysfunction., XXVIIth International Conference on Polyphenols &8th Tannin Conference, Nagoya, Sep. 2014.
16.
Rie Mukai, Naoko Matsui, N Matsumoto, N.T. Dang, Takeshi Nikawa, Hisao Nemoto and Junji Terao : Anti-Oxidative Flavonoid suppresses disuse muscle atrophy in denervation mice., XXVIIth International Conference on Polyphenols &8th Tannin Conference., 2014.
17.
Junji Terao : Revisit of dietary carotenoids as antioxidants in biomembrane:Efficacy in the prevetion of photoaging, Ineternational society of Neutraceuticals and Functional Foods Conference, Taipei, Nov. 2013.
18.
Junji Terao : Prenylation modulates the bioavailability of dietary flavonoids, International Conference on Polyphenols and Health, Buenos Aires, Oct. 2013.
(Keyword)
ICPH
19.
Arisa Ochi, Katsuya Hirasaka, Ayako Maita, Shigetada Kondo, Tomoyuki Kawamura, Hisao Nemoto, Rie Mukai, Junji Terao, Taesik Gwang, Inho Choi and Takeshi Nikawa : Development of anti-ubiquitination oligopeptide, Cblin:Cbl-b inhibitor that prevents unloading-induced muscle atorophy., The 29th International Symposium on Space Technology and Science, Nagoya, Jun. 2013.
20.
Yauhen Bandaruk, Rie Mukai and Junji Terao : Attenuation of monoamine oxidase-A activity and its expression level in the brain as possible mechanism of antidepressant-line action of flavonoids., The 17th Biennial Meeting of Society for free radical international, Mar. 2013.
21.
Rie Mukai, Horikawa Hitomi, Fujikura Yutaka, Kaeko Murota, Kawamura Tomoyuki, Hisao Nemoto and Junji Terao : Effect of prenylation on the bioavailability of dietary flavonoids, The International Society for Nutraceuticals and Functional Foods, Dec. 2012.
22.
Junji Terao : Effect of prenylation on the bioavailability of dietary flavonoids, Annual Conference ofISNFF2012, Hawaii, Dec. 2012.
Kohno Shohei, Shigetada Kondo, Katsuya Hirasaka, Ayako Maita, Yuushi Okumura, Rie Mukai, Junji Terao, Akira Higashibata and Takeshi Nikawa : Regulation of the Gene Expression of Cbl-b Ubiquitin Ligase in Skeletal Muscle During Unloading Conditions., 7th General Meeting of the International Proteolisis Society, 米国, Oct. 2011.
28.
Hironori Yamamoto, Tsuji Mitsuyoshi, Rie Mukai, T Inakuma, Junji Terao and Eiji Takeda : Dietary quercetin and onion powder could prevent immobilization induced bone loss in rats, 5th International Conference on Polyphenols and Health (ICPH), Barcelona, Oct. 2011.
29.
Rie Mukai, Tomoyuki Kawamura, Yutaka Fujikura, Hitomi Horikawa, Hisao Nemoto and Junji Terao : Bioavailability and muscle atrophy-preventive effect of prenylated flavonoids, International Conference on Polyphenols and Health, Sitges, Barcelona, Spain, Oct. 2011.
30.
Junji Terao : Funtional food factors for the prevention of muscle atrophy, 2nd NAPA meeting, Gyeongyu,KOREA, Feb. 2011.
31.
Rie Mukai, Takeshi Nikawa, Hisao Nemoto, Hironori Yamamoto, Eiji Takeda, Yoshichika Kawai and Junji Terao : Disuse muscle atrophy is suppressed by antioxidative flavonoid quercetin, International Symposium on Free Radical Research: Contribution to Medicine, Kyoto, Jan. 2011.
32.
Junji Terao : Multitargets of dietary flavonoids in modulation of oxidative stress, International symposium on Free Radical Research, Kyoto, Jan. 2011.
33.
Rie Mukai, Tomoyuki Kawamura, Yutaka Fujikura, Moemi Hayashi, Hisao Nemoto, Takeshi Nikawa, Hironori Yamamoto, Eiji Takeda and Junji Terao : Disuse muscle atrophy is prevented by flavonoids, 2010 International Chemical Congress of Pacific Basin Societies, Honolulu, Dec. 2010.
34.
Tomoyuki Kawamura, Moemi Hayashi, Rie Mukai, Junji Terao and Hisao Nemoto : Chemical Synthesis of O-Methylated and/or C-Prenylated Flabonoid Analogues, Pachifichem 2010, Honolulu, Dec. 2010.
Junji Terao : Innovation of fiunctional food research in Japan, International Symposium of the KoSFoST, Chonanng,KOREA, Nov. 2010.
37.
Junji Terao : Central nervous system as a possible target of dietary quercetin and its metabolites, International conference on Netraceuticals and Functional Foods, Bali,INDONESIA, Oct. 2010.
38.
Junji Terao and Yoshichika Kawai : Possible riole of -(-) epicatehin gallate in antiatherosclerotic actions of tea catehins, International Conference on Ocya Shizuoka, Shizuoka, Oct. 2010.
39.
Junji Terao : Processing and cooking effects on bioavailability and biefficacy of dietary flavonoids, Korean Society of Nutrition International symposium, Seoul, Jun. 2010.
40.
Junji Terao : Dietary querctin as a multifunctional food factor, 2010 International symposium on functional foods for, Taichung,Taiwan, Jan. 2010.
41.
Rie Mukai, Hitoshi Ashida, Takeshi Nikawa and Junji Terao : Nuclear accumulation of flavonol aglycone in cultured cells detected with a fluorescence microscope, 4th International Conference on Polyphenol and Health, Harrogate, United Kingdom, Dec. 2009.
42.
Junji Terao, Kaeko Murota and Yoshichika Kawai : Flavonoid paradox between biological acitivity and bioavailability:insight into their delivery to the target site, 4th International conference on polyphenols and health, Harrogate,UK, Dec. 2009.
43.
Junji Terao, Kaeko Murota and Yoshichika Kawai : Prevention of athrosclerosis by functional food factors, Itary-Japan Symposium on Foods and, Tokyo, Oct. 2009.
44.
Junji Terao : Quercetin as a multifunctional food factor, MoRST.FRST-JST Functional food workshop, Palmerston,North New Zealand, Jul. 2009.
45.
Mika Adachi, Jun-ichi Morishige, Tamotsu Tanaka, Junji Terao, Kiyoshi Satouchi and Akira Tokumura : Lysophosphatidic acid in foods and herbs protects gastric ulcer in rats under water-immersion stress, 4th international conference on phospholipase A2 and lipid mediators, Vol.Final program and abstracts book, 131, Tokyo, May 2009.
46.
Junji Terao and Yoshichika Kawai : Mechanistic approach to anti-atherosclerotic effect of tea catechins, 2008 Internaitonal Symposium on Chronic Disease and LOHAS Foods, Jeju KOREA, Oct. 2008.
47.
Junji Terao, Kaeko Murota and Yoshichika Kawai : Antioxidative flavonoid quercetin:metabolic conversion behand its antiatheroslcerotic sffect, International symposium on Lipid peroxidation 2008, Karuizawa, Oct. 2008.
48.
Junji Terao, Kaeko Murota and Yoshichika Kawai : Availability and behavior od dietary flavonoids in the target site, 2nd international symposium on translational research on natural produts and cancer, Lonavala, Mumbai, India, Dec. 2007.
49.
Junji Terao, Kaeko Murota and Yoshichika Kawai : Antioxidant activity and physiological significance of flavonoid metabolites, The 9th International Conferecen on Mechanisms of antimutagenesis and anticarcinogenesis, Jeju Island, Korea, Dec. 2007.
50.
Takashi Kinoshita, Zsolt Lepp, Yuko Shiba, Yoshichika Kawai, Junji Terao and Hiroshi Chuman : Chemoinformatics and QSAR Study of Flavonoids, Tokyo, Dec. 2007.
51.
Junji Terao : Onion flavonoids as anti-atherosclerotic food factors, Satellite sympsium in kagoshima ICPH, Kagoshima, Nov. 2007.
52.
Junji Terao, Yoshichika Kawai and Kaeko Murota : Vegetable flavonoids and cardiovascular disease, 10th _Asian Congress of Nutrition, Taipei, Sep. 2007.
53.
Junji Terao : Dietary flavonoid quercetin: Its absorption, metabolism and antioxidant activity., 3rd International symposium on phytochemicals, Seoul, Oct. 2006.
54.
Hiroyuki Sakakibara, Yuki Izawa, Jun-ichiro Nakajima, Shujiro Seo, Toshiaki Tamaki, Yoshichika Kawai and Junji Terao : Antidepressant effects of polyphenol rich herbal medicine, Ginkgo biloba, extracts in behavioral models, 232 nd American Chemical Society Meeting & Exposition, San Francisco, Sep. 2006.
55.
Junji Terao and Yoshichika Kawai : Accumulation of antioxidative flavonoids in the target site, SFRR's 13th Biennial Meeting, Davos, Switzerland, Aug. 2006.
56.
Kenji Fukuzawa, A. Fujiwara, Akira Tokumura, Junji Terao and Jansuz M. Gebicki : Measurement of phosphatidylcholine hydroperoxides in membranes by the ferric-xylenol orange (FOX) assay, XIII the Biennial Meeting of the Society for Free Radical Research International, Davos, Aug. 2006.
57.
Hiroyuki Sakakibara, Kaori Ishida, Yuki Izawa, Yuko Minami, Satomi Saito, Yoshichika Kawai, Butterweck Veronika, Toshiaki Tamaki, Yutaka Nakaya and Junji Terao : Effects of Ginkgo biloba Extract on Rat brain Function, 2nd International Conference on Polyphenols and Health, California Davis, Davis, Oct. 2005.
58.
Junji Terao : Metabolic conversion of polyphenols and regulation of their biological effect., 2nd International Conference on Polyphenols and Health., Davis, USA, Oct. 2005.
59.
Hiroyuki Sakakibara, Kaori Ishida, Yuki Izawa, Yuko Minami, Saito Saromi, Yoshichika Kawai, Butterweck Veronika, Toshiaki Tamaki, Yutaka Nakaya and Junji Terao : Effects of forced swimming stress on rat brain function, 2005 COE International Conference ''Biological Mechanism for Stress Control'', Tokushima, Aug. 2005.
60.
Junji Terao : Molecular mechanism for cell function of dietary flavonoids., 2ndSFRR Asia/3rdISNA, Shanghai, Jun. 2005.
61.
Junji Terao : Anti-atherosclerotic effect of dietary flavonoid quercetin: Implication of its intestinal absorption and metabolism., 2004 International Symposium on Functional Foods for Health in Taiwan, Taipei, May 2004.
62.
Junji Terao, C Kamada, M Kameyama, J-H Moon and EL daSilva : Anti-atherosclerotic effect of dietary flavonoids: Quercetin glucoside attenuates lipid peroxidation in rabbit aorta., SFRR's 12th Biennial Meeting, Buenos Aires , Argentina, May 2004.
Rie Mukai, 鈴木 里穂, 田中 義章, 嶺川 祥子, Yoshichika Kawai and Junji Terao : ケルセチン抱合体代謝物に対する腎臓の脱抱合化反応の解析, 日本農芸化学会2016年度大会, Mar. 2015.
13.
高橋 正子, 庄野 裕美, Rie Mukai, 井出 晋太郎, 朝武 宗明, Yasuhiro Hamada and Junji Terao : タマネギケルセチンの生体利用性に対する食べ合わせの効果-同時摂取食材がケルセチン血漿濃度に与える影響-, 日本農芸化学会2015年度大会, Mar. 2015.
14.
Airi Otsuka, Tetsuya Shiuchi, Sachiko Chikahisa, Junji Terao and Hiroyoshi Sei : Physical exercise reduces social avoidance induced by defeated stress, 92nd Annual Meeting of The Physiological Society of Japan, Mar. 2015.
Airi Otsuka, Tetsuya Shiuchi, Sachiko Chikahisa, Junji Terao and Hiroyoshi Sei : Effect of restricted high fat diet intake on behavior induced by social defeat stress, The 37th Annual Meeting of the Japan Neuroscience Society, Sep. 2014.
17.
Rie Mukai, 松井 直子, Takeshi Nikawa and Junji Terao : ケルセチンはミトコンドリアの機能を保つことで廃用性筋萎縮を予防する, 第8回 日本ポリフェノール学会学術大会, Aug. 2014.
Junji Terao : 食事性フラボノイドの脳移行と酸化ストレス抑制, 日本薬剤学会28年会特別講演, May 2013.
25.
Yauhen Bandaruk, Rie Mukai and Junji Terao : Accumulation of flavonoids quercetin and luteolin in SH-SY5Y cells and their effects on Monoamine oxidase-A, 日本農芸化学会2014年度大会, Mar. 2013.
河村 知志, 林 萠未, Rie Mukai, Junji Terao and Hisao Nemoto : An efficient method for C-prenylation of flavonoid and its application to the synthesis of related compounds, 第37回反応と合成の進歩シンポジウム, Nov. 2011.
36.
Rie Mukai and Junji Terao : 抗酸化フラボノイドの廃用性筋萎縮予防効果―モデル動物による評価―, 第11回AOB研究会, Jul. 2011.
37.
Rie Mukai, 水口 八重子, 藤倉 温, 河野 尚平, Takeshi Nikawa, Yoshichika Kawai and Junji Terao : ケルセチンの経口摂取による廃用性筋萎縮予防の可能性, 第65回日本栄養・食糧学会大会, May 2011.
38.
河村 知志, 林 萠未, Rie Mukai, Junji Terao and Hisao Nemoto : A highly efficient prenylation at C-8 position of flavanone analogues, 日本薬学会年会, Mar. 2011.
39.
林 萠未, 河村 知志, Rie Mukai, Junji Terao and Hisao Nemoto : Development of a method for C-prenylation of flavonoids and its application to the synthesis of related compounds, 日本薬学会第131年会, Mar. 2011.
40.
河村 知志, Rie Mukai, 林 萠未, Junji Terao and Hisao Nemoto : 廃用性筋萎縮抑制作用を有するフラボノイドのC-プレニル化と活性評価, 日本薬学会年会, Mar. 2011.
Rie Mukai, 藤倉 温, Takeshi Nikawa, Hironori Yamamoto, Eiji Takeda and Junji Terao : 廃用性筋萎縮モデルマウスにおけるケルセチンの筋重量低下抑制効果, 日本農芸化学会2010年度大会, Mar. 2010.
48.
Koji Hirozumi, Tatsusada Yoshida, Yoshichika Kawai, Junji Terao and Hiroshi Chuman : QSAR of DPPH Activity of Flavonoids Based on Ab Initio MO Studies of Hydrogen Radical Abstraction of Phenols, 第37回構造活性相関シンポジウム, Nov. 2009.
Junji Terao : A role of dietary flavonoids in oxidative stress of the central nervous system, Antioxidans and Redox Process in Health Bilateral Meeting Brazil-Japan, Oct. 2013.
Accumulation and Metabolism of Antioxidative Flavonoids on Oxidative Stress-Targeted Organs and Expression Mechanism of Their Activity (Project/Area Number: 16380089 )
Analysis of Changes in Reactive Oxygen Acavenging Compounds durin Cooking (Project/Area Number: 13480028 )
Development of Peroxidized Lipid Detection Method using TLC Blot (Project/Area Number: 12556020 )
Mechanism for the protection of oxidative stress in digestive tract by phytic acid (Project/Area Number: 11660127 )
Design of Diet Menu with Free Radical Scavenging Activity and Analysis of Its Availability (Project/Area Number: 11480024 )
Evaluation of Active Oxygen Scavenging Activity of Vegetables during Cooking (Project/Area Number: 09480002 )
Inhibition of mutagen formation by antioxidants in foods (Project/Area Number: 61560143 )