Protective effect of jakyak-gamcho-tang extract and its constituents against t-BHP-induced oxidative damage in HT22 cells.

The present study investigated whether Jakyak-Gamcho-Tang (JGT, Shaoyao-Gancao-tang) and its constituents have the protective effect against tert-butyl hydroperoxide (t-BHP)-induced cytotoxicity on hippocampal HT22 cell line. JGT consists of two medicinal herbs, Paeoniae Radix (PR) and Glycyrrhizae Radix (GR). In contrast to treating with t-BHP alone, pre-treatment of HT22 cells with JGT, PR and GR (50-400 microg/ml) for 3 hours significantly increased the cell viability in a concentration-dependent manner. In addition, JGT, PR and GR exhibited the scavenging activity in both 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and superoxide anion assays. Among the tested extracts, PR showed the most potent protective and antioxidative activities. These results suggest that PR acts as an antioxidant and this property may contribute to the neuroprotective activity of JGT extract.