Fig. 4. Effect of sun ginseng (SG) on gene expression of antioxidant enzymes in HepG2 cells. To analyze the effects of SG on superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) gene expression by a real time polymerase chain reaction analysis, cells were incubated with the indicated concentration of SG (5, 10, and 20 μg/mL) for 24 h. Data represent the mean±SD of triplicate experiments. Differences were considered significant at ^*p<0.05 and ^**p<0.01 vs. negative control (NC).