Protective effect of icariin on DNA against radical-induced oxidative damage.

Icariin (2-(4'-methoxylphenyl)-3-rhamnosido-5-hydroxyl-7-glucosido-8-(3'-methyl-2-butylenyl)-4-chromanone) is a flavonoid with a rhamnose as ligand. It is the major component in Herba epimedii, widely used for the treatment of atherosclerosis and neuropathy in Chinese traditional medicine, and its antioxidative property has attracted much scientific interest. The major objective of this work is to determine the antioxidative effect of icariin against oxidative DNA damage induced by 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH). The oxidative damage of DNA was followed by measuring the formation of carbonyl compounds that can react with thiobarbituric acid (TBA) to form thiobarbituric acid reactive substance (TBARS). We found that icariin protects DNA against AAPH-induced oxidative damage in a concentration-dependent manner, although it does not affect the rate of AAPH-induced DNA damage. This result indicates that icariin is a concentration-dependent chemopreventor in protecting DNA against radical-induced damage.