3.12.1. ABTS+ Radical Cation Method

A stock solution of ABTS was prepared, which consists of the reaction of an aqueous solution of ABTS (7 mM) with one of potassium persulfate (2.45 mM); 10 mL of each was taken and allowed to react for 12–16 h in the dark. One milliliter of the stock solution was taken and diluted with methanol. Then, 150 μL of the freshly prepared ABTS solution was mixed with 50 μL of the supernatant and allowed to react for 30 min, after which the absorbance was read at 732 nm with the Cytation^TM 5 multimode reader. This procedure was carried out in duplicate.

With the absorbance values, the percentage of inhibition was calculated using the following Equation:

where A₀ is the absorbance of ABTS and A₁ is the absorbance of the sample.