Application of an Oxygen Electrode to Evaluate Superoxide Anion-scavenging Ability

The ability to scavenge superoxide anion radicals ((center dot)O(2)(-)) was determined using an oxygen electrode. The method is based on the determination of (center dot)O(2)(-) generated by the reaction of nitrilotriacetatoiron(III) with hydrogen peroxide and a decrease in the concentration of (center dot)O(2)(-) by a scavenging reaction, converting into a change in the generation of oxygen molecules through an electron-transfer reaction from (center dot)O(2)(-) to nitrilotriacetatoiron(III). Oxygen generation, which enhanced proportionally with an increase in the concentration of hydrogen peroxide, was inhibited depending on the concentration of superoxide dismutase. Hence, we applied the present reaction system to evaluate the (center dot)O(2)(-)-scavenging abilities of an antioxidant, measuring the degree of inhibition of oxygen generation using an oxygen electrode. A good correlation was obtained between the present method and conventional colorimetry, monitoring the formation of blueformazan by the reaction of nitro blue tetrazolium with (center dot)O(2)(-), to estimate the (center dot)O(2)(-)-scavenging activities of antioxidants.