2.10.1. DPPH Radical Scavenging Activity

The antioxidant activity of fBRE was assayed by its scavenging effect on 2, 2-diphenyl-1-picrylhydrazyl (DPPH) as a free radical. Briefly, a 0.2 mM DPPH solution was prepared with methanol. Each sample was diluted with distilled water and then 100 µL of the diluted sample was mixed with 400 µL of prepared DPPH solution in a 1.75 mL tube. The mixture was covered with aluminum foil to protect it from light and maintained at 37 °C for 30 min. After the reaction, the absorbance of the resulting solution was measured at 517 nm against a blank. Ascorbic acid was used as a standard, and the percentage of DPPH quenched was calculated every minute as follows: % DPPH quenched = [1 − (Abs (sample)/(Abs (control) × 100].