Antioxidant and apoptotic effects of korean white ginseng extracted with the same ratio of protopanaxadiol and protopanaxatriol saponins in human hepatoma HepG2 cells.

To investigate the antioxidative effects of ginsenosides [protopanaxadiol derivatives (PD):protopanaxatriol derivatives (PT) = 1:1] from the roots of Korean ginseng, cell viability, malondialdehyde (MDA) production, antioxidant enzyme activities, and expressions of apoptosis were analyzed after pretreatment of human hepatoma HepG2 cells with H(2)O(2). Cell death was increased through H(2)O(2) treatment dose dependently, and a dose of ginseng extract (PD:PT = 1:1) of 18.6 microg/mL was enough to derive it in reverse. MDA production was reduced through the administration of ginseng extracts even with more intensive H(2)O(2) treatments. Through the use of even low levels of ginseng extract (e.g., 1.86 microg/mL), catalase (CAT) activity was easily reduced from the plateau induced by H(2)O(2). The glutathione peroxidase activity was no better than that of CAT. We assume that ginseng extract acts as an antioxidant even when effective levels of ginseng differ. A ginseng extract dose of 18.6 microg/mL increased the apoptotic expression of oxidative stressed signals, such as c-Jun-N-terminal kinase and stress-activated protein kinase expressions, and mitochondrial cytochrome c released caspase-3 activation; however, these expressions changed with higher doses of ginseng.