The scavenging effects of the samples on the DPPH• were
monitored according to the method of Ramadan et al. [19]
with minor modifications. The DPPH• solution was freshly
prepared in MeOH at a concentration of 1.75×10−4 mol/L.
About 2.0 mL of DPPH• solution was added to 2.0 mL of the
appropriately diluted extracts, and the mixture was vibrated
for 20 s at room temperature. The absorbance of the mixture
was recorded at 517 nm after reacting for 1 h in the dark. A
control, in which the sample was replaced by MeOH, was
measured by the same way.