In vitro inhibitory activities of six gypenosides on human liver cancer cell line HepG2 and possible role of HIF-1α pathway in them.

During our phytochemical investigation of Gynostemma pentaphyllum (Thunb.) Makino, six gypenosides (compounds 1-6) were isolated and determined, including two with a 21,23-epoxy group (1, 2), two with a 21,23-lacton skeleton (3, 4), and two with usual side-chain (5, 6). In this research, we studied their possible in vitro inhibitory activities on cancer cell line HepG2 under hypoxic conditions, explored the role of HIF-1α pathway in them and discussed the potential antitumor gradients and conduct analysis of structure-activity relationships (SAR). They and gensenoside-Rg3 were tested for different assays. Compounds 1-4 showed moderate antitumor activities against HepG2 by MTT assay, inhibited HIF-1α mRNA expression, as well as disturbing HepG2 migration and invasion, superior to Rg3. Correlations were found for gypenosides with different side chain on inhibiting HepG2 proliferation activity, the ones have epoxy structure showed the highest effect. These results supported the potential application of G. pentaphyllum as a functional food for hepatoprotection.