Effect of isoquercitrin on superoxide dismutase activity. The SOD significantly increased in all isoquercitrin pretreated cells. There was a significant elevation of SOD with the presence of isoquercitrin in a dose-dependent manner. Data are mean and S.E. values from three independent experiments (n = 3). #p < 0.001, relative to control cells. *p < 0.05, **p < 0.01 and ***p < 0.001, relative to cells treated only with 6-OHDA.