Abstract

destroy potential oxidants, and to scavenge ROS. Thus, A simple, automated test measuring the ferric reduc-oxidative stress-induced tissue damage is minimized. ing ability of plasma, the FRAP assay, is presented as However, an absolute or relative deficiency of antioxia novel method for assessing ''antioxidant power.'' Fer-dant defenses may lead to a situation of increased oxiric to ferrous ion reduction at low pH causes a colored dative stress, and this may be associated with both ferrous-tripyridyltriazine complex to form. FRAP val-the causes and consequences of a variety of disorders, ues are obtained by comparing the absorbance change including coronary heart disease and cancer (6-13). at 593 nm in test reaction mixtures with those con- Tests which measure the combined antioxidant effect taining ferrous ions in known concentration. Ab-of the nonenzymatic defenses in biological fluids may sorbance changes are linear over a wide concentration be useful in providing an index of ability to resist oxidarange with antioxidant mixtures, including plasma, tive damage (13-19). Most tests of ''total antioxidant and with solutions containing one antioxidant in puri-power'' used to date have measured the ability of fied form. There is no apparent interaction between plasma to withstand the oxidative effects of reactive antioxidants. Measured stoichiometric factors of Tro-species purposefully generated in the reaction mixture.