Abstract: The effect of chicoric acid on free radical-induced oxidative damage to proteins was evaluated in this paper. Two different paradigms including metal-catalyzed oxidation induced by Cu2+/H2O2 and alkylperoxyl radicals formed by azo initiator 2, 2’-azobis (2-amidinopropane) hydrochloride (AAPH) were used to induce oxidative damage to proteins including bovine serum albumin (BSA) and mouse liver and brain proteins. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot were applied to determine the level of oxidative protein damage. Results showed that chicoric acid in the range of 100–1 000 μmol/L significantly inhibited oxidative protein damage induced by Cu2+/H2O2. However, chicoric acid at high concentration could induce oxidative damage to mouse tissue proteins. Chicoric acid protected the proteins against oxidative damage induced by AAPH-derived alkylperoxyl radicals in a dose-dependent manner. In conclusion, chicoric acid has different protective effects on oxidative protein damage in both paradigms.

Key words: chicoric acid, protein, oxidative damage, Cu2+/H2O2, alkylperoxyl radicals