To study on antioxidant effects in the liver of 40-week-old mouse, the sample were orally pretreated 5mg/kg/day for 5 days with red ginseng saponin components(total saponin, protopanaxadiol saponin, protopanaxatriol saponin, ginsenoside-Rd, ginsenoside-Re, compound-K) for 5 days. The ability of saponin to protect the mouse liver from oxidative damage was examined by determining the activity of superoxide dismutase(SOD), glutathione peroxidase(GPx) and the contents of glutathione, the level of malondialdehyde, The only protopanaxadiol among the ginseng saponin fractions was significantly increased the hepatic SOD activity(p<0.01). The red ginseng saponin induced a slight increase of GPx activity, especially ginsenoside Rd, compound K and protopanaxatriol treatments significantly increased its activity. The content of glutathione was significantly increased by total saponin, protopanaxadiol and ginsenoside Rd(p<0.01), but the oxidized glutathione level was lowered in all the red ginseng saponin. Finally, the level of malondialdehyde was significantly decreased by ginsenoside Rd and protopanaxadiol. In conclusion, protopanaxadiol and ginsenoside Rd among the saponin fraction were especially increased in the activity of hepatic antioxidative enzyme and decreased the lipid peroxidation that was expressed in term of MDA formation. This comprehensive antioxidant effects of red ginseng saponin seems to be by a certain action of saponin other than a direct antioxidant action.

Ginsenosides have been regarded as the principal components, responsible for the pharmacological and biological activities of ginseng. Absorption of major ginsenosides at the gastrointestinal tract was extremely low, when ginseng taken orally. In order to improve the absorption and bioavailability, transformation of major ginsenosides into more active and valuable minor ginsenoside is much required. In this present study, We isolated a lactic acid bacteria Leuconostoc fallax LH3 from the Korean fermented food Kimchi, which have higher β-glucosidase activity. Using the ethanol precipitated curd enzyme of Leuconostoc fallax LH3, we investigated the biotransformation of ginsenoside Rd at different experimental condition to increase transformation. The maximum convertion was supported at 30 ℃ and decreased when temperatures increased. In order to optimize the effect of pH, the curd enzyme was mixed 20 mM sodium phosphate buffer (pH 3.5 to pH 8.0). Ginsenoside Rd was almost hydrolyzed between pH 7.0 and pH 9.0, but not hydrolyzed above pH 10.0. Ginsenoside Rd was hydrolyzed after 24 hrs incubation, but whereas the ginsenoside F2 was appeared from 36 hrs, and all ginsenoside Rd was transformed to F2 after the 60 hrs incubation. Based on this study, the curd enzyme of Leuconostoc fallax LH3 transformed the ginsenoside Rd at the 30℃ and the pH optimum of 7.0 to 9.0 after the 60 hrs incubation time.