Icariin Inhibits Hydrogen Peroxide-Mediated Cytotoxicity by Up-regulating Sirtuin Type 1-Dependent Catalase and Peroxiredoxin

Previous studies suggest that flavonol icariin protects against neuron injury after oxygen and glucose deprivation by increasing SIRT1. This study demonstrates that icariin can inhibit H2O2-induced neurotoxicity. The neuroprotection of icariin enhances the antioxidant capacity through both a direct scavenging effect on over-produced free radicals and an indirect stimulating effect on the expression and activity of cellular antioxidant enzymes including catalase (CAT) and peroxiredoxin 1 (Prx1). The mechanism may be partially involved in the up-regulation of SIRT1. The SIRT1 antagonist can partly block this neuroprotection and the enhancement of CAT/Prx1 by icariin. These results indicate that the effect of icariin on H2O2-induced neurotoxicity is dependent on increasing SIRT1 and provides a potentially novel pharmacological strategy for stroke prevention and/or treatment.