The DPPH radical-scavenging activity was determined using
the method proposed by Wojdylo et al. (2007) with some modi-
fications. The DPPH• solution (4.0 mL, absorbance of 0.700 ± 0.02
at 517 nm) was added to 0.1 mL of sample, which was properly
diluted and mixed thoroughly. The reaction mixture was stored
at room temperature (∼23 ◦C) for 6 h, and absorbance was immediately
recorded at 517 nm by using a Shimadzu UV-2550 UV–vis
spectrophotometer (Kyoto, Japan). Trolox standard solution (final
concentration 50–800 mol/L) was prepared and assayed under
the same conditions. Results were expressed in terms of mmol
Trolox equivalent antioxidant capacity per 100 g dry weight(TEAC).
All determinations were performed in triplicate.