A comparative study of superoxide dismutase activity assays in Crocus sativus L. corms

Superoxide dismutase catalyzes the breakdown of superoxide radical anion and provides the first line of defense against oxygen toxicity. Its vital importance has made it the subject of numerous investigations. Several assays have been proposed for the detection and quantitation of superoxide dismutase activity, but their use has remained controversial and no comparative studies have been reported. In this investigation, three commonly used methods for the measurement of superoxide dismutase activity were compared to assay the enzyme in Crocus sativus L. corm extract. The methods, based on the competition between the enzyme itself and a superoxide scavenger, involved cytochrome c reduction, nitro blue tetrazolium reduction, and pyrogallol autooxidation, respectively. Because of its accuracy, reproducibility, simplicity, and cost benefit, the latter method was preferred.