DPPH was determined according to the Brand-
Williams et al. (1995) technique, with some
modifications. The stock solution was prepared by
mixing 2.5 mg of DPPH radical with 100 mL of pure
methanol. The solution was adjusted at an absorbance of
0.7±0.02 at 515 nm. Trolox (6-hydroxy-2, 5, 7, 8-
tetramethylchromane-2-carboxylic) was used as a
standard and 80% methanol was used as a blank, 3.9 mL
of DPPH radical were placed in a test tube and 100 μL
of the extract (2:8 dilution) were added. The mixture
was shaken in a vortex and kept 30 min in the dark.
Absorbance was then read in an UV-VIS VARIAN
CARY 50 BIO spectrophotometer, at a wavelength of
515 nm. Results were expressed in EC50 (concentration
of antioxidant required to reduce the absorbance of the
radical by 50%) in gFW mL-1. Analyses were
performed in triplicate per each RS.