4.10. Free Radical 2.2-Diphenyl-1-picrylhydrazyl (DPPH) Scavenging Assay

For each of the two extracts (aqueous and ethanolic), the antioxidant activity (AA) was determined by using the DPPH scavenging assay. 0.0012 g of DPPH was thus dissolved in 50 mL of methanol to obtain a concentration of 6 × 10⁻³ M of DPPH. For the aqueous extract, 5 mg of powder was dissolved in 1 mL of methanol, while for the ethanolic extract, 5 mg of powder was dissolved in a mixture of 0.5 mL of methanol and 0.5 mL of distilled water. Then, 50 μL of the prepared solution was added to 2 mL of DPPH and placed in the dark for 30 min. The absorbance was finally measured at 515 nm. The antioxidant activity was calculated according to the following equation:

The absorbance (ABS) control is the absorbance of DPPH + solvent, and ABS sample is the absorbance of the DPPH + sample, where the control was prepared by taking 2 mL of the prepared DPPH solution (DPPH + methanol) without the extract.