The ABTS (2,20-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) antioxidant activity was determined using ABTSþ radical cation decolorization assay (Re et al., 1999), with little modification. Briefly, 7 mmol/L ABTS solution and 2.45 mmol/ L potassium persulfate were mixed in 1:1 ratio and allowed to stand in the dark for 12e16 h to produce ABTS radical cation (ABTSþ) stock solution. The ABTSþ working solution (3 mL) and 30 mL of blank, standard or sample were mixed and the absorbance was measured at 734 nm after 6 min using a spectrophotometer. The blank was run with methanol-80 and standard curve was prepared using 0.3e1.5 mmol Trolox/L.