Different Apoptotic Effects of Triterpenoid Saponin-Rich Gypsophila oldhamiana Root Extract on Human Hepatoma SMMC-7721 and Normal Human Hepatic L02 Cells

Abstract

The roots of Gypsophila oldhamiana are rich in triterpenoid saponins with antitumor properties. Although previous reports have revealed the anticancer potency of some Gypsophila species, the underlying molecular mechanisms of this activity have not been studied in detail. The purpose of the present study was to prepare a triterpenoid saponin-rich G. oldhamiana root extract (TGOE) determined by LC-electrospray ionization (ESI)-MSⁿ for biological studies and to evaluate the different anti-proliferative activities and apoptotic effects of TGOE on human hepatoma SMMC-7721 and normal human hepatic L02 cells. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that TGOE selectively inhibited the proliferation of SMMC-7721 cells in a dose-dependent manner with IC₅₀ value of 19.50±3.63 µg/mL, while the cytotoxic effects of TGOE on L02 cells were much lower with IC₅₀ value of 40.48±3.74 µg/mL. Analysis of apoptotic morphological changes and flow cytometry indicated that TGOE might preferentially induce apoptosis in SMMC-7721 cells, while exhibited much lower effects on L02 cells. Western blot analysis showed that the different apoptotic effects of TGOE on SMMC-7721 and L02 cells were due to different protein regulation of caspase-3 and mitogen activated protein kinases (MAPKs). TGOE significantly activated caspase-3 and increased the phosphorylation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), while decreased the phosphorylation of p38 in SMMC-7721 cells. However, the expression of these proteins was not statistically changed in L02 cells, except for the up-regulation of p38 phosphorylation. These results suggest that TGOE may have potential beneficial effects against hepatocellular carcinoma.