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en: Phytochemical studies on traditional herbal medicines based on the ethnopharmacological information obtained by field studies

en: Traditional herbal medicines, which have been used in the matured traditional medical systems as well as those have been used in ethnic medical systems, are invaluable resources of drug seeds. Ethnobotanical and ethnopharmacological survey may provide useful information of these herbal medicines, which are valuable for searching new bioactive molecules. From this viewpoint, we have been performing the ethnobotanical and ethnopharmacological field studies in Yunnan Province and Guangxi Zhuang Autonomous Region, China, and Mongolia. Phytochemical studies on traditional herbal medicines were performed based on the information obtained by our ethnobotanical survey. Herbal medicines used in Uzbekistan and Bangladesh were also investigated on the basis of the ethnopharmacological information obtained from collaborative researchers in the respective regions. Some studies were carried out for searching active substance(s) based on bioassay-guided fractionation and isolation. Over 150 new molecules were isolated in these studies, and their various biological activities were also demonstrated. This review summarizes the results of phytochemical studies of those traditional herbal medicines as well as biological activities of the isolated molecules.

en: Journal of Natural Medicines

ja: Journal of Natural Medicines


en: Characteristic metabolites of Hypericum plants: their chemical structures and biological activities

en: Plants belonging to the genus Hypericum (Hypericaceae) are recognized as an abundant source of natural products with interesting chemical structures and intriguing biological activities. In the course of our continuing study on constituents of Hypericum plants, aiming at searching natural product-based lead compounds for therapeutic agents, we have isolated more than 100 new characteristic metabolites classified as prenylated acylphloroglucinols, meroterpenes, ketides, dibenzo-1,4-dioxane derivatives, and xanthones including prenylated xanthones, phenylxanthones, and xanthonolignoids from 11 Hypericum plants and one Triadenum plant collected in Japan, China, and Uzbekistan or cultivated in Japan. This review summarizes their chemical structures and biological activities.


en: Bromopyrrole alkaloids from Okinawan marine sponges Agelas spp.

en: In our continuing study for structurally and biogenetically interesting natural products from marine organisms, Okinawan marine sponges Agelas spp. were investigated, resulting in the isolation of 18 unique alkaloids including five dimeric bromopyrrole alkaloids (1-5), ten monomeric bromopyrrole alkaloids (6-15), and three conjugates of monomeric bromopyrrole alkaloid and hydroxykynurenine (16-18). In this mini-review, the isolation, structure elucidation, and antimicrobial activities of these alkaloids are summarized.

en: Chemical & Pharmaceutical Bulletin

ja: Chemical & Pharmaceutical Bulletin


en: Search for structurally unique bioactive natural products

ja: 特異な化学構造を有する生物活性天然物質の探索

en: In our continuing search for structurally and biologically interesting metabolites from marine organisms and plants, we investigated the constituents of Okinawan marine sponges and Hypericum plants, resulting in the isolation of several new and unique natural products. Their structures were elucidated on the basis of spectroscopic analyses and chemical conversions. Novel bromopyrrole alkaloids, nagelamides X-Z, were isolated from a sponge Agelas sp. Heteroaromatic alkaloids, hyrtimomines A and B, were isolated from a sponge Hyrtios sp. together with bisindole alkaloids, hyrtimomines C-E. An oxylipin with a trimeric structure, manzamenone O, was obtained from a sponge Plakortis sp. Dimeric eudesmane sesquiterpenes connected through various linker moieties, halichonadins K-L, were isolated from a sponge Halichondria sp., and isomalabaricane triterpenes, stelliferins J-N, were obtained from a sponge Rhabdastrella sp. The investigation for the extracts of Hypericum plants gave new meroterpenes, acylphloroglucinols, and xanthones. Biyoulactones A-E are meroterpenoids from the roots of Hypericum chinense. Acylphloroglucinols, chipericumines A-D, and highly prenylated xanthones, biyouxanthones A-D, were also isolated from the same origin. Tricyclic meroterpenes, yezo'otogirins A-C, and liner meroterpenos, yojironins A and B, were isolated from Hypericum yezoense and Hypericum yojiroanum, respectively.

en: Journal of the Pharmaceutical Society of Japan

ja: 薬学雑誌


en: Prenylated acylphloroglucinols and meroterpenoids from Hypericum plants

en: Heterocycles

ja: Heterocycles