Determination of the antioxidant capacity by ABTS assay

ABTS activity was achieved as before defined by Kim et al.[11] with some adjustments. The extracts were used in 15.625–1,000 μg/mL serial dilution. The mixture was mixed with 7 mM ABTS + and 2.45 mM K₂S₂O₈ (8:12 v/v ratio), then kept it in a dark place for 16 h. After that, the blend was diluted in absolute ethanol and the absorbance was measured at 750 nm. The ascorbic acid was used as a calibration curve. Finally, added 180 μL of the ABTS + solution to each well. Afterward, kept it in a dark place for 30 min and evaluated absorbance at 750 nm wavelength. The ABTS scavenging percentage was estimated as follows: (1). Moreover, calculations were applied to obtain the IC₅₀.