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 H(2) O(2) -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 H(2) O(2) -induced neurotoxicity is dependent on increasing SIRT1 and provides a potentially novel pharmacological strategy for stroke prevention and/or treatment.