Evaluation of antioxidant activity by chemiluminescence.

A sensitive and simple chemiluminescent method for measuring antioxidant activity was developed. The method is based on antioxidant-dependent quenching of chemiluminescence generated from lipid hydroperoxide and isoluminol/microperoxidase reagent. This method was used to evaluate the antioxidant ability of various antioxidants by measuring the half-inhibition concentration (IC50). The results were compared to those measured with an oxygen electrode method. They were approximately similar in pattern and level, although there was some discrepancy, which was assumed to be due to a possible difference in the reaction mechanisms of the two methods. This method also suggested an additive property of antioxidant activity with different antioxidants. Thus, the present method was used to evaluate the total antioxidant activity in biological tissues such as rat serum, human saliva, and green tea.