3.6.3. ABTS Radical Scavenging Activity

The ABTS assay was determined according to Re et al. [53] with slight modifications regarding the quantities of the antioxidant solution. The radical solution was prepared with ABTS and potassium persulfate, diluted in water to a final concentration of 2.45 mM, and left in the dark for 16 h to allow for radical development. The solution was diluted to reach the absorbance measures around 0.7 at 734 nM. Then, 2.95 mL of the ABTS•<sup>+</sup> solution was mixed with 0.05 mL of each sample. The absorbance was measured after 3 min of the reaction at 734 nM. Deionized water was used as a blank. The scavenging effect was calculated according to the equation:

$$\text{Scavenging activity} \left( \% \right) \ = \left[ 1 - \left( \text{A sample/A control} \right) \right] \times 100 \tag{5}$$

where A sample is the absorbance of the mixture of sample and ABTS•+; A control is the absorbance of the control (ABTS•<sup>+</sup> solution).

The results were expressed as Trolox equivalent antioxidant activity (TEAC) values (mM Trolox).
