A new dammarane-type saponin from Gynostemma pentaphyllum induces apoptosis in A549 human lung carcinoma cells.

Gynostemma pentaphyllum has been widely used as a traditional herb for its antioxidant and immunostimulatory activities. We have previously reported several useful dammarane-type saponins with cytotoxicity against A549 human lung cancer cells from heat-processed G. pentaphyllum. In this study, a new dammarane-type saponin, 20(S)-2α,3β,12β-tetrahydroxydammar-3-O-β-d-glucopyranoside (namely gypenoside Jh1), was isolated from the ethanol extract of heat-processed G. pentaphyllum using column chromatography and semi-preparative HPLC. Gypenoside Jh1 exhibited strong cytotoxicity against A549 cells in a concentration-dependent manner, which was associated with apoptotic cell death characterized by morphological changes, Hoechst 33258 nuclear staining, Annexin V and propidium iodide binding and mitochondrial potentials assay. Quantitative analysis using flow cytometry also showed that the proportion of apoptotic cells was increased after gypenoside Jh1 treatment. These findings indicated that gypenoside Jh1 showed antiproliferative effects on A549 cells and mitochondrial-dependent pathway is involved in gypenoside Jh1-induced apoptosis.