Cytotoxic polyacetylenes from the twigs of Ochanostachys amentacea

Bioassay-guided investigation of the twigs of Ochanostachys amentacea using LNCaP (hormone-dependent human prostate cancer) cells as a monitor led to the isolation of three alkynes, the known (S)-17-hydroxy-9,11,13,15-octadecatetraynoic acid (minquartynoic acid, 1) and two novel analogues, (S)-17,18-dihydroxy-9,11,13,15-octadecatetraynoic acid (2) and (S)-17-hydroxy-15E-octadecen-9,11,13-triynoic acid (3). Compounds 1-3 were tested against a panel of human tumor cell lines and found to be significantly cytotoxic.

Four new stilbenoid C-glucosides isolated from the stem bark of Shorea hemsleyana

Four new C-glucopyranosides of resveratrol oligomers, hemsleyanosides A-D, were isolated from the bark of Shorea hemsleyana. The structures were established on the basis of spectroscopic evidence, including 1H-1H and 1H-13C long-range couplings and nuclear Overhauser effect experiments in the NMR spectrum.

Stilbenoids isolated from stem bark of Shorea hemsleyana

Two new stilbene glucosides [(+)-alpha-viniferin 13b-O-beta-glucopyranoside and resveratrol 12-C-beta-glucopyranoside] and two new resveratrol oligomers, hemsleyanols A and B, were isolated from the bark of Shorea hemsleyana along with four known resveratrol oligomers. The structures of the isolates, including the relative configurations, were established by spectroscopic data involving long-range coupling and nuclear Overhauser effect experiments.

Oligostilbenoids in stem bark of Vatica rassak

Three resveratrol oligomers, vaticanols. A, B and C, as well as three known stilbenoids, resveratrol, piceid and epsilon-viniferin were isolated from the stem bark of Vatica rassak (Dipterocarpaceae). Their structures were determined by the analysis of NMR spectral data including the application of 2D methods.