Abstract—A method for the screening of antioxidant activity is reported as a decolorization assay applicable to both
lipophilic and hydrophilic antioxidants, including flavonoids, hydroxycinnamates, carotenoids, and plasma antioxidants.
The pre-formed radical monocation of 2,29-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•1) is generated by
oxidation of ABTS with potassium persulfate and is reduced in the presence of such hydrogen-donating antioxidants.
The influences of both the concentration of antioxidant and duration of reaction on the inhibition of the radical cation
absorption are taken into account when determining the antioxidant activity. This assay clearly improves the original
TEAC assay (the ferryl myoglobin/ABTS assay) for the determination of antioxidant activity in a number of ways. First,
the chemistry involves the direct generation of the ABTS radical monocation with no involvement of an intermediary
radical. Second, it is a decolorization assay; thus the radical cation is pre-formed prior to addition of antioxidant test
systems, rather than the generation of the radical taking place continually in the presence of the antioxidant. Hence the
results obtained with the improved system may not always be directly comparable with those obtained using the original
TEAC assay. Third, it is applicable to both aqueous and lipophilic systems