4.4.1. DPPH Radical Scavenging Activity

The DPPH· scavenging activity was assessed by referring to the reported method [48]. A 100 µL properly diluted sample solution was mixed with 100 µL of DPPH solution (0.15 mmol/L) on a 96-well plate, after storing at room temperature in dim light for 30 min, and then the absorbance value (As) was read at 517 nm. Methanol was used to replace the sample as a negative control (Ab), while Vc and BHT were the positive controls. The percentage of DPPH radical clearance was calculated using the following Formula (1), and the DPPH· scavenging activity was expressed as the IC₅₀ value (μg/mL), which was obtained by plotting the percentage of scavenging versus the concentration.