The determination of the free radical-scavenging effect of the samples on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical was based on the method proposed by Rojo et al. (2009) with modification. A 1 ml methanol–water (8:2 v/v) as the negative control and the sample (the positive control) were added to 6 ml of 100 μmol/l DPPH solutions in methanol–water (8:2 v/v). The mixtures were thoroughly vortex-mixed and incubated at room temperature for 30 min. A decrease in the absorbance was determined at 517 nm against the blank (methanol–water, 8:2 v/v) using a UV–VIS spectrophotometer (Shimadzu UV-1601PC, Japan). The results were expressed as μmol of Trolox equivalents per hundred grams of the sample (μmol TEAC/100 g sample).