Chemical Constituents of Phoebe poilanei and Their Cytotoxic Activity

Two new flavonol glycosides, rhamnocitrin 3- O-α-L-rhamnopyranosyl-(1→6)-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (1) and quercetin 3- O-6- Z- p-coumaroyl-β-D-glucopyranosyl-(1→2)-α-L-rhamnopyranoside (2), along with 3 flavonol glycosides, isoquercitrin (3), rutin (4), and quercetin 3- O-α-L-rhamnopyranosyl-(1→6)-β-D-galactopyranoside (5), and two known sesquiterpenes, alismol (6) and spathulenol (7), were isolated from the leaves of Phoebe poilanei Kosterm. Their chemical structures were elucidated by analyses of their high-resolution electrospray ionization mass spectral data and nuclear magnetic resonance spectral data and comparison with those reported in the literature. Two sesquiterpenes 6 and 7 were found to exhibit moderate cytotoxic activity with IC50 values ranging from 21.6 to 29.8 µM.

Structure and hypolipidaemic activity of fucoidan extracted from brown seaweed Sargassum henslowianum

The aim of this study is to elucidate the structure and investigate the hypolipidaemic activity of a fucoidan extracted from brown seaweed Sargassum henslowianum collected at Hai Van-Son Cha peninsula, Hue province, Vietnam by using tandem electrospray ionisation mass spectrometry. The results demonstrated that the fucoidan has α(1 → 3)-linked L-fucopyranose backbone and sulphate groups occupied mostly at C-2, C-4 and sometimes at C-3 position of fucose residues. The results of in vivo bioactivity examination revealed that the fucoidan in the dose of 100 mg/kgP/day by oral administration helped decrease cholesterol, triglyceride and LDL-cholesterol levels on obese mice.