Antiplasmodial activity of novel stilbene derivatives isolated from Parthenocissus tricuspidata from South Korea

New stilbene glycoside, piceid-(1 -> 6)-beta-D-glucopyranoside (compound 2, Fig. 1), was isolated from the MeOH extract of the leaves of Parthenocissus tricuspidata (Vitaceae) together with four known compounds, piceid (compound 1, Fig. 1), resveratrol (compound 3, Fig. 1), longistylin A (compound 4, Fig. 1), and longistylin C (compound 5, Fig. 1). Their structures were determined spectroscopically, particularly by 2D nuclear magnetic resonance (NMR) spectroscopic and chemical analysis. The antiplasmodial activity of isolated compounds were determined in vitro against a chloroquine-sensitive strain of Plasmodium falciparum (D10). Among the compounds isolated, piceid-(1 -> 6)-beta-D-glucopyranoside (2) had the most potential inhibition, with inhibitory concentration (IC50) values of 5.3 mu M. To our knowledge, antiplasmodial activity of functional group position of stilbene is now being reported for the first time in this study. The result shows that the 3, 4'-position in stilbenes might play an essential role in antiplasmodial activity.