DPPH Free Radical Assay
The anti-DPPH activity of antioxidant compounds was examined according to the method developed by Delfanian et al. (2015). Briefly, 100 µL of antioxidant solutions (10–50 µM) was added to 3 mL of methanolic solution of DPPH (). The absorbance of solution (Asample) was read at 517 nm against a blank (Acontrol) after 30 min incubation at The ability of phenolic antioxidants in radical scavenging (%) was investigated from Eq. (1):
\(\%RSA=\frac{A_{\text{control}}-\ A_{\text{sample}}}{A_{\text{control}}}\ \times 100\)(1)
The IC50, [AH] required to scavenge 50% of DPPH, was determined by interpolating the linear regression analysis.