Xiu-Wei Yang

Bio-assay guided isolation and identification of α-glucosidase inhibitors from the leaves of Aquilaria sinensis

Eight α-glucosidase inhibitors including four new compounds were isolated from the 70% aqueous ethanolic extract of leaves of Aquilaria sinensis (Lour.) Gilg by activity-directed fractionation and purification processes. The ethanolic extract was first separated into petroleum ether, ethyl acetate, n-butanol and water soluble fractions and screened for inhibitory activity against α-glucosidase. Further activity-directed investigation lead to the isolation of four new compounds with moderate inhibitory activity, viz, aquilarisinin (1), aquilarisin (2), hypolaetin 5-O-β-D-glucuronopyranoside (3) and aquilarixanthone (4) from the n-butanol fraction, and four known compounds showing potent activity including mangiferin (5), iriflophenone 2-O-α-L-rhamnopyranoside (6), iriflophenone 3-C-β-D-glucoside (7) and iriflophenone 3,5-C-β-D-diglucopyranoside (8) from the most potent ethyl acetate fraction. The structures of these compounds were determined by extensive spectroscopic analyses, including IR, UV, ESIMS, HRESIMS, 1D and 2D NMR.

Trollioside, a new compound from the flowers of Trollius chinensis

A new compound, named trollioside, together with nine known compounds, proglobeflowery acid, isoswertisin, isoswertiajaponin, cirsimaritin, veratric acid, vitexin, orientin, β-sitosterol and daucosterol, were isolated from the ethanol extract of the dried flowers of Trollius chinensis Bunge. The isolation and structural determination of these compounds are discussed.

Two new lanostane triterpenoids from Poria cocos

Two new lanostane triterpenoids, 29-hydroxypolyporenic acid C (4) and 25-hydroxypachymic acid (5), together with three known compounds, ergosta-7,22-dien-3β-ol (1), polyporenic acid C (2) and pachymic acid (3), were isolated from the 95% ethanolic extract of the sclerotium of Poria cocos (Schw.) Wolf. Their structures were determined by extensive spectroscopic analyses, including IR, UV, ESITOF–MS, HRESI–MS, 1D and 2D NMR data (1H NMR, 13C NMR, 1H–1H COSY, NOESY, HSQC and HMBC).

Alkaloids from the seeds of Sterculia lychnophora (Pangdahai)

Two alkaloids, named sterculinine I and sterculinine II, together with thirteen known compounds were isolated from the ethanol extract of a well-known Chinese traditional drug, Pangdahai (the seeds of Sterculia lychnophora Hance). Their structures were elucidated by NMR, UV, IR and MS spectroscopic analysis.

Dibenzocyclo-octadiene lignans from Kadsura heteroclita

Abstract From the stems of Kadsura heteroclita , new dibenzocyclo-octadiene lignans, named heteroclitins A-E, were isolated together with the known compounds, kadsurin and interiorin. Their structures were determined by spectroscopic means.

New sesquiterpenoids from the dried flower buds of Tussilago farfara and their inhibition on NO production in LPS-induced RAW264.7 cells.

Three new sesquiterpenoids, 1α-(3″-ethyl-cis-crotonoyloxy)-8-angeloyloxy-3β,4β-epoxy-bisabola-7(14),10-diene (1), 7β-angeloyloxy-14-hydroxy-notonipetranone (2) and 1α-hydroxy-7β-(4-methylsenecioyloxy)-oplopa-3(14)Z,8(10)-dien-2-one (3) were isolated from ethanolic extract of the dried flower buds of Tussilago farfara L., along with nine known sesquiterpenoids (4-12). All of these compounds were evaluated for their effect on the inhibition of nitric oxide (NO) production induced by lipopolysaccharide in macrophage cell line RAW 264.7 and exhibited inhibitory activity on NO production in a dose-dependent manner. 7β-(4-Methylsenecioyloxy)-oplopa-3(14)E,8(10)-dien-2-one (8) was proved to be the best among these tested sesquiterpenoids with an IC(50) value of 10.80 μM.

Studies on the alkaloid constituents of Evodia rutaecarpa (Juss) Benth var. bodinaieri (Dode) Huang and their acute toxicity in mice

Six alkaloids (1–6) have been isolated from the fruits of Evodia rutaecarpa (Juss) Benth var. bodinaieri (Dode) Huang, two of which are new compounds, identified as 2-undecyl-4(1H)-quinolone (4) and 1-methyl-2-undecanone-10′-4(1H)-quinolone (5); the known compounds were identified as rutaecarpine (1), evodiamine (2), 1-methyl-2-undecyl-4(1H)-quinoline (3) and 2-undecanone-10′-4(1H)-quinolone (6). Compounds 1–5 were evaluated for their acute toxicity.

Biotransformation of columbianadin by rat hepatic microsomes and inhibition of biotransformation products on NO production in RAW 264.7 cells in vitro.

Columbianadin (CBN, 1), 1-[(8S)-8,9-dihydro-2-oxo-2H-furo[2,3-h]-1-benzopyran-8-yl]-1-methylethyl-[(2Z)-2-methyl-2-butenoic acid]ester is a coumarin-type compound and one of the main bioactive constituents of the underground part of Angelica pubescens Maxim. f. biserrata Shan et Yuan. Although numerous investigations have been undertaken to study the biological activities of CBN, such as analgesic, anti-inflammatory, calcium-channel blocking, and platelet aggregation inhibiting functions, little attention has been paid to its metabolism and/or biotransformation. Biotransformation of CBN by rat liver microsomes in vitro was studied, and thirteen biotransformation products including eight hitherto unknown compounds [columbianadiratimetins A-H (3-10)] and five known compounds [columbianadin oxide (2), (+)-2,3-dihydro-4-hydroxy-2-(1-hydroxy-1-methylethyl)-5-benzofurancarboxaldehyde (11), oroselol (12), columbianetin (13), and vaginol (14)] were produced by liver microsomes from rats pre-treated with sodium phenobarbital. The structures of these compounds were elucidated on the basis of extensive spectroscopic analyses which included IR, UV, EIMS, HRESIMS, 1D NMR and 2D NMR, respectively. The inhibition of CBN and its main biotransformation products on nitric oxide production induced by lipopolysaccharide was assayed in RAW 264.7 cells at concentrations ranging from 10 to 200 μM to evaluate the biological significance of biotransformation.

Poriacosones A and B: two new lanostane triterpenoids from Poria cocos.

Two new lanostane triterpenoids, poriacosones A (8) and B (9), together with eight known compounds were isolated from the sclerotia of Poria cocos (Schw.) Wolf (Polyporaceae), and identified by spectroscopic analysis, including IR, UV, CD, ESI-TOF-MS, HR-SIMS, 1D-, and 2D-NMR spectra. The structures of the new compounds were established as 3α,16α-dihydroxy-24-oxolanost-7,9(11)-dien-21-oic acid (8) and 3β,16α-dihydroxy-24-oxolanost-7,9(11)-dien-21-oic acid (9).

New triterpenoids from the stems and leaves of Panax ginseng.

Three new dammarane-type triterpene saponins ginsenosides Rh(18) (1), Rh(19) (3) and Rh(20) (4), along with two new triterpene sapogenins 12β,23(R)-epoxydammara-24-ene-3β,6α,20(S)-triol (2) and dammara-(20E)22,25-diene-3β,6α,12β,24S-tetrol (5) were isolated from the stems and leaves of Panax ginseng C. A. Mey. Their structures were elucidated on the basis of spectral evidence and comparisons with literature data.