Analysis of 2,2’-Azino-Bis(3-Ethylbenzothiazoline-6-Sulfonic Acid) Radical Scavenging Activity

Briefly, 5.0 mL of ABTS (7.0 mM) was incubated with 88 μL of potassium persulfate (2.5 mM) for 12–16 h at room temperature in the dark. The absorbance of the reaction mixture at 734 nm was adjusted to 0.7 ± 0.02 using 0.1 M phosphate buffer (pH 7.4). Next, the samples (0.5 mL) were incubated with 2.0 mL of the ABTS solution for 30 min at room temperature. IC₅₀ (mg/mL) was defined as the effective concentration at which the extract scavenged 50% ABTS⋅. The absorbance of the reaction mixture at 734 nm was compared with that of the blank. Vc and P. vicina powder reaction mixtures served as controls. The ABTS⋅ scavenging activity was calculated as follows:

where A₁ is the absorbance of the test sample; A₂ is the absorbance of the sample without the ABTS⋅ solution, and A₀ is the absorbance of the blank (without samples).