Antioxidant Assays in Pharmacological Research

Antioxidants research has become active to a greater extent in many fields. The publications on antioxidants' potential, their availability from vitamins, flavonoids, polyphenols etc has increased too many folds since past decade. Several reviews have also been published on validated and specific assays. This review summarises the versatility of antioxidants against the free radicals, their dual mechanism of action and the chemical principles of many antioxidant assays. The antioxidants assay is a complex topic due to the unavailabilty of a standard assay. This review intends to be comprehensive to cover almost all the reported assays which have few influence and applications. Choosing an adequate assay is critical to investigate the antioxidant activity of foods and biological samples. Two general types such as; lipid peroxidation associated assays and electron or radical scavenging assays are widely used for different antioxidant studies have been discussed here. The former includes, β-carotene bleaching assay, anti-lipid peroxidation assay involving TCA-TBA solution and the latter includes ABTS (2, 2'-azino-bis3-ethylbenzthiazoline-6-sulfonic) radical cation decolorisation assay, DPPH (1, 1-Diphenyl-2-picryl-hydrazyl) radical scavenging assay, ferric reducing antioxidant power assay, superoxide anion scavenging activity assay, ferrous ion-chelating assay etc. The chemistry behind all the above mentioned assays has been reviewed here emphasising the need of discovery of a convenient method for the quick quantitation of antioxidants.