2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS•+)

The ABTS radical cation (ABTS•+) is a stable free radical primarily used as a chromogenic substrate in biochemical assays to determine the antioxidant capacity of various substances (Re et al., 1999). It is generated through the oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) by agents such as potassium persulfate or manganese dioxide (Sigma-Aldrich). In the presence of hydrogen-donating or electron-donating antioxidants, the blue-green radical is reduced to its colorless neutral form, a change that is monitored spectrophotometrically at 734 nm (PubChem CID 5364430). While it is a standard tool in the pharmaceutical industry for screening the radical-scavenging potential of new drug candidates, it is not a physiological target, receptor, or enzyme within the human body. Therefore, it does not have a direct role in disease pathogenesis or therapeutic mechanisms in vivo.

Other names

ABTS radicalABTS radical cation2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) radicalABTS+

The ABTS radical cation is reduced by antioxidant compounds through electron transfer or hydrogen atom transfer, leading to the decolorization of the solution which is measured spectrophotometrically (Re et al., 1999).