Applications of a new method for measuring the total oxyradical scavenging capacity in marine invertebrates

A new method is described for measuring the total oxyradical scavenging capacity (TOSC) in biological tissues. The TOSC-assay is based on the reaction between peroxyl radicals and α-keto-γ-methiolbutyric acid which is oxidized to ethylene. The presence within the tissues of molecules that scavenge for peroxyl radicals generated by thermal homolysis of 2,2′ azo-bis-amidinopropane quantitatively reduce ethylene production. Cytosol from invertebrates showed a higher ROO ° absorbance capacity than that of rat liver and in all the species endogenous soluble antioxidants provided greater protection than proteins. The expected contribution of GSH, ascorbic acid and uric acid accounted for only 35% of the measured TOSC values. This method is useful for assessing the biological resistance to oxidative stress and its relationship to environmental pollutants in quantifiable terms.