High-throughput superoxide anion radical scavenging capacity assay.

A high-throughput superoxide anion radical (O2(•-)) scavenging capacity assay based on the xanthine oxidase/xanthine reaction system was developed and validated in the present study. The reaction conditions including detection wavelength, concentrations of reactant components, reaction temperature, reaction time, pH, terminator reagent, and sample dissolving solvents were optimized. The accuracy and reliability of the assay were assessed by evaluation of linearity (r(2) = 0 .9513-0.9957), precision (intraday RSD 1.13-4.05% and interday RSD 2.13-5.62%), accuracy (95.64-97.42% recovery), and stability (RSD 2.62-6.19%), as well as comparison with the conventional colorimetric method. The EC50 values obtained by the current method and the conventional assay were highly correlated (r > 0.99). This high-throughput O2(•-) scavenging assay may be used for screening and estimating potential superoxide anion radical (O2(•-)) scavengers, especially food extracts and natural products with a very small amount of test material.