4.10. ABTS Radical Scavenging Assay

The ABTS radical scavenging effect was determined following the method described by Lee and Cho [5] with slight modifications. The 7.4 mM ABTS⁺ and 2.6 mM potassium persulphate solutions prepared in ethanol were mixed at a 1:1 ratio and left in the dark at room temperature for about 14 h to make an ABTS⁺ stock solution. The stock solution was diluted with ethanol to get an absorbance value of 0.2–1.0 at 735 nm. Two hundred microliters of stock solution and 20 μL sample extracts and Trolox as the standard (Supplementary Figure S1) were put into a 96-well plate. The reaction mixture was allowed to react for 30 min and then the absorbance was measured at 735 nm using a spectrophotometer (Thermo, Multiskan Spectrum, Vantaa, Finland). The DPPH radical scavenging potential was expressed as Trolox equivalent.