An [2,20-azinobis (3-ethyl-benzothiazoline-6-sulphonate)],ABTS radical-scavenging assay was conducted as previously described (Re et al. 1999).ABTS? ions were generated by blending 7.4 mM
ABTS stock solution with 2.6 mM K2S2O8, which was then diluted in phosphate buffer (pH 7.4) and
equilibrated to an OD734 of 0.7 ± 0.02. Then,different sample concentrations (25 ll) were mixedwith 100 ll of ABTS? solution and the A734 recorded; 95 % (v/v) ethanol served as the blank
control. ABTS?-scavenging activity was calculated by the following equation:Scavenging activity ð%Þ ¼ ð Þ A0 AS =A0 100;where A0 is the blank control absorbance and AS is thesample absorbance.