2.6.2. ABTS radical scavenging activity
The ABTS assay was proposed by Re et al. (1999). ABTS radical
was produced by reacting 2 mL of 7 mM ABTS solution with 1 mL
of 7.35 mM potassium persulfate in the dark at room temperature
for 12 h. The resulting solution was diluted with 5 mM phosphate
buffer (pH 7.4) to obtain an absorbance in the range of 0.68–0.72 at
734 nm. Stock solutions of aqueous alcohol extracts were diluted
1:30 (v/v) with methanol to produce sample solutions, while stock
solutions of ethyl acetate and water extracts were diluted 1:10 (v/v)
with methanol. Then, diluted ABTS•+ solution (4.85 mL) was mixed
with 150 L of sample solution. The absorbance was recorded
immediately after 6 min at 734 nm.