2.3. Antioxidant Activity: FRAP Assay

Antioxidant potential was measured using the ferric reducing ability of plasma (FRAP) assay according to the procedure described by Benzie and Strain [57], with minor modifications. Briefly, 100 μl of 1% (v/v) test sample was mixed with 900 μl of freshly prepared FRAP reagent, consisting of 20 mM ferric chloride (in water), 10 mM TPTZ (in 40 mM HCl), and 300 mM sodium acetate buffer (pH 3.6) in a volume ratio of 1 : 1 : 10, respectively. Absorbance after a 4 min incubation was measured at λ = 593 nm by spectrophotometry (Ultrospec 2100 pro; GE Healthcare Life Sciences, Little Chalfont, UK; [57]). Ferrous sulphate (FeSO₄, in water) was used as a reference standard.