SOD1 and hepatocellular carcinoma: By studying its effects on the cell activity and the secretion of antioxidant substances, such as glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), and nitric oxide (NO) in human umbilical artery smooth muscle cell (HUASMC) and hepatocellular carcinoma (HCC) cell (HepG2) damaged by hydrogen peroxide (H2O2) oxidation, the antioxidant effect of TKPP was explored.