Correlations between Common Antioxidant Assays

Reactive oxygen species (ROS) are highly reactive and toxic products of aerobic metabolism that can cause oxidative stress and tissue damage. Antioxidants are molecules that function to slow or prevent the formation of ROS by scavenging free radicals. There are many different assays that have been produced to measure antioxidant capacity, and the four that will be focused on are the oxygen radical absorbance capacity (ORAC) assay, the total phenolics assay, the ABTS [2,2’-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid)] assay, and the ferric reducing ability of plasma (FRAP) assay. This study examined the correlations between the assays to determine which assays are the most useful and applicable. Our results demonstrated that all four of these antioxidant assays are very significantly correlated and are reliable to measure antioxidant content. We would rank the ABTS assay as the most useful and most effective assay due to its simplicity and its ability to measure both water-soluble and lipid-soluble antioxidants. The assays investigated here can be applied to measure the antioxidant content of various foods to determine which foods have high antioxidant content and thus have added health benefits.