Chemical Constituents of Phoebe poilanei and Their Cytotoxic Activity

Abstract

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.