Jing-Hua Yang

New monoterpenoid coumarins from Clausena anisum-olens

Two new monoterpenoid coumarins: anisucumarin A (1) and B (2), a pair of epimers, were isolated from Clausena anisum-olens. Their structures were established based on extensive spectroscopic analyses.

A New 2′-Oxygenated Flavone Glycoside from Litsea glutinosa (Lour.) C. B. Rob.

A new 2′-oxygenated flavone glycoside, named glutin, was isolated from Litsea glutinosa (Lour.) C. B. Rob. along with four known compounds. The structure was identified as 2′,5,7-trihydroxy-6-methoxyflavone 2′-O-β-D-glucopyranoside (1) on the basis of extensive spectroscopic analysis.

Diterpenoid alkaloids from aconitum episcopale

Abstract Three new diterpenoid alkaloids, liaconitine A (N-ethyl-1α,6α,16β,18-tetramethoxy-13β-ol-2,3-dehydroaconitane-8-acetate-14-anisoylate), B (N-ethyl-1α,6α,16β,18-tetramethoxy-13β-ol-2,3-dehydroaconitane-8,14-dianisoylate and C (N-ethyl-1α,6α,16β,18-tetramethoxy-8-ethoxy-13β-ol-2,3-dehydroaconitane-14-anisoylate) have been isolated from the roots of Aconitum episcopale. The structures of the new compounds were established by spectroscopic methods and reduction of liaconitine A to the known alkaloid, crassicauline A.

Anisucoumaramide, a Bioactive Coumarin from Clausena anisum-olens

A new coumarin, anisucoumaramide (1), and a new δ-truxinate derivative, anisumic acid (2), were isolated from Clausena anisum-olens. Their structures were elucidated from extensive NMR and MS data. The absolute configurations of the coumarins were assigned using the experimental and calculated electronic circular dichroism data. Anisucoumaramide (1) represents the first example of a naturally occurring coumarin of which the terpenoidal side chain does not comply with the biosynthesis isoprene rule due to the presence of an unprecedented acetamido motif directly connected with the terpenoidal side chain. The δ-truxinate derivative was isolated from Clausena species for the first time. Compound 1 showed high selectivity for the MAO-B isoenzyme and inhibitory activity in the nanomolar range. Putative biosynthesis pathways toward 1 and 2 are proposed.

Clausenain B, a phenylalanine-rich cyclic octapeptide from Clausena anisum-olens

A new cyclic octapeptide, named clausenain B, was isolated by a multi-step chromatography procedure from Clausena anisum-olens. Its structure was established as cyclo(-Phe(1)-Ser-Leu(1)-Phe(2)-Phe(4)-Gly-Leu(2)-Phe(3)-) (1) based on extensive spectroscopic studies and chemical evidence. Clausenain B (1) is a phenylalanine-rich cyclic octapeptide.

Ethnobotany, phytochemistry, and pharmacology of the genus Litsea: An update

ETHNOPHARMACOLOGICAL RELEVANCE The genus Litsea is one of the most diverse genera of evergreen trees or shrubs belong to Lauraceae, and comprises roughly 400 species of tree that are distributed abundantly throughout tropical and subtropical Asia, North and South America. Litsea species have been used globally in traditional medicine for the treatment of various diseases including influenza, stomach aches, diarrhea, diabetes, vomiting, bone pain, inflammation, illness related to the central nervous system and other ailments. The purpose of this review is to provide updated, comprehensive and categorized information on the ethnobotany, phytochemistry and pharmacological research of Litsea species in order to explore their therapeutic potential and evaluate future research opportunities. MATERIALS AND METHODS All the available information on Litsea species was actualised by systematically searching the scientific literatures including Chinese, Korean, Japanese, Indian, and South American herbal classics, library catalogs and scientific databases (PubMed, SciFinder, Web of Science, Google Scholar, VIP and Wanfang). The Plant List, International Plant Name index and Scientific Database of China Plant Species were used to validate scientific names. RESULTS 407 secondary metabolites have been reported from Litsea species. Litsea Species are sources of secondary metabolites with interesting chemical structures (alkaloids, lactones, sesquiterpenes, flavonoids, lignans, and essential oils) and significant bioactivities. Crude extracts, fractions and phytochemical constituents isolated from Litsea show a wide spectrum of in vitro and in vivo pharmacological activities including anticancer, anti-inflammatory, antimicrobial, antioxidant, antidiabetic, anti-HIV, insecticidal, etc. CONCLUSIONS From data collected in this review, the genus Litsea comprises a wide range of therapeutically promising and valuable plants, and has attracted much attention owing to its multiple functions. Many traditional uses of Litsea species have now been validated by modern pharmacology research. Deep and systematic phytochemical investigation of the genus Litsea and the pharmacological properties, especially its mechanism of action and toxicology, to illustrate its ethnomedicinal use, explore the therapeutic potential and support further health-care product development will undoubtedly be the focus of further research. Therefore, detailed and extensive studies and clinical evaluation of Litsea species should be carried out in future for the safety approval of therapeutic applications.

A New O-Terpenoidal Coumarin from Clausena anisum-olens Merr.

A new O-terpenoidal coumarin 1, named hekumarone, was isolated from the leaves and twigs of Clausena anisum-olens Merr. (Rutaceae) collected in Hekou County in Yunnan Province, P. R. China. Structure elucidation and unambiguous NMR assignments for the title compound was carried out on the basis of 1D and 2D NMR experiments.

Megastigmane O-glucopyranosides from Litsea glutinosa

0009-3130/12/4802-0346 2012 Springer Science+Business Media, Inc. 1) Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, School of Chemical Science and Technology, Yunnan University, Kunming 650091, P. R. China, fax: 0871 5035538, e-mail: yangjh@ynu.edu.cn; yangjhkm@hotmail.com; 2) Yunnan Academy of Tobacco Science, Kunming 650031, P. R. China; 3) Yunnan Institute of Product Quality Supervision and Inspection, Kunming 650031, P. R. China. Published in Khimiya Prirodnykh Soedinenii, No. 2, March–April, 2012, pp. 310–312. Original article submitted January 12, 2011. Chemistry of Natural Compounds, Vol. 48, No. 2, May, 2012 [Russian original No. 2, March–April, 2012]

Chemical constituents of Litsea szemaois

0009-3130/11/4701-0122 2011 Springer Science+Business Media, Inc. Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, School of Chemical Science and Technology, Yunnan University, Kunming 650091, P. R. China, fax: 0871 5035538, e-mail: yangjh@ynu.edu.cn. Published in Khimiya Prirodnykh Soedinenii, No. 1, p. 108, January–February, 2011. Original article submitted September 29, 2009. Chemistry of Natural Compounds, Vol. 47, No. 1, March, 2011 [Russian original No. 1, January–February, 2011]

New Cytotoxic Steroid from Stachyurus imalaicus var. himalaicus

A phytochemical study of the ethanolic extract of Stachyurus imalaicus var. himalaicus was undertaken and as a result a new polyoxygenated steroid, named stachsterol ((20S)-20, 25-dihydroxy-4-cholesten-3-one, 1) and three known ecdysteroids, 20-hydroxyecdysone (2), 20-hydroxyecdysone-20, 22-monoacetonide (3) and polypodine B-20,22-monoacetonide (4), were isolated. Their structures were elucidated by spectroscopic methods, including UV, NMR, MS and HR-MS. The purified product 1 was found to have in vitro cytotoxic activity against human Hela cell lines with an IC50 value of 2.5 microg/mL. This is the first time that phytoecdysteroids have been found in the genus Stachyurus.