Damarane-type Saponins from Gynostemma longipes and their Cytotoxic Activity

Two new damarane-type saponins, named gylongiposides II-III (1 and 2), along with one known compound, (23S)-3β,20ξ,21ξ-trihydroxy-19-oxo-21,23-epoxydammar-24-ene 3-O-α-L-rhamnopyranosyl-(1-->2)-[-D-xylopyranosyl-(1-->3)]-α-L-arabinopyranoside, were isolated from the leaves of Gynostemma longipes C.Y.Wu. Their structures were determined by 1D- and 2D-NMR and HR-ESI-MS spectra. Compounds 1-3 exhibited moderate activity against four human cancer cell lines, A-549, HT-29, OVCAR, and MCF-7, with IC50 values ranging from 9.8 +/- 2.1 to 49.6 +/- 2.6 μM.