þ radical cation decolorization assay (Re et al., 1999), with
little modification. Briefly, 7 mmol/L ABTS solution and 2.45 mmol/
L potassiumpersulfateweremixed 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 mLof
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.