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

ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) radical cation is a stable free radical used extensively in biochemical research to evaluate the total antioxidant capacity (TAC) of various substances (PubChem CID 5360881). It is generated by the oxidation of ABTS with an oxidizing agent like potassium persulfate (Re et al., 1999). In the presence of hydrogen-donating antioxidants, the blue-green chromophore of the ABTS radical is reduced back to its colorless neutral form (ScienceDirect). This reduction can be measured spectrophotometrically at specific wavelengths, typically 734 nm, to quantify the antioxidant potential of a sample (NIH/PubMed). While it serves as a critical tool for screening potential therapeutic agents with antioxidant properties, it is not a biological target found within the human body. Consequently, it does not play a direct role in disease pathology or physiological signaling. Its primary utility lies in the standardization of antioxidant activity measurements relative to a reference compound like Trolox, often referred to as the Trolox Equivalent Antioxidant Capacity (TEAC) assay (Wikipedia). It is not considered a drug target for therapeutic intervention but rather a diagnostic or analytical reagent.

Other names

ABTS radicalABTS cation radical2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radicalABTS•+

Reduction of the ABTS radical cation by electron or hydrogen atom transfer from antioxidant molecules, resulting in the loss of its characteristic blue-green color.