Nine new dammarane saponins from Gynostemma pentaphyllum.

Nine new dammarane saponins, 1-9, were isolated from the MeOH extract of the aerial part of Gynostemma pentaphyllum, an edible plant of the Cucurbitaceae family, that grows wildly in China. Their structures were elucidated by 1D- and 2D-NMR analysis, as well as by chemical degradation. Aglycons 21,24-cyclopentyldammar-25-ene of 6 and 7, and 21,24-cyclopentyldammarane of 8 and 9, were novel. Compounds 1, 4, and 8 showed moderate antitumor activities against stomach cancer cells SGC-7901 and liver cancer cells BEL-7402.