Validation of Best Detection Methods for Measuring Oxidative Stress

Abstract

We assessed the antioxidative effects of quercetin-feeding on ddY strain male mice by measuring luminol-amplified chemiluminescence that was enhanced by a hydrophilic free radical initiator 2,2′-azobis(2-amidinopropane) dihydrochloride. Quercetin suppressed chemiluminescent intensity in a dose-dependent manner in vitro with a half-inhibition concentration (IC50) of 3×10−8 M, which was lower than the value of synthetic antioxidant 2,6-di-tert-butyl-p-cresol (IC50: 7×10−7 M). Lysosomal (12 000×g pellet) and supernatant fractions obtained from the livers of mice fed a diet containing 0.2% quercetin for 7 days showed more inhibition of chemiluminescent intensity than those from non-treated mice. Quercetin feeding also resulted in the inhibition of lipid peroxidation as determined by a thiobarbituric acid reactive substance test which detected suppression of the release of lysosomal enzymes induced by lipophilic free radical initiator 2,2′-azobis(2,4-dimethylvaleronitrile). These results probably reflect radical quenching activity of quercetin, indicating that the measurement of chemiluminescence is a useful tool for the assessment of total antioxidant activity in biological systems.