2.4.6. Assay for Ferric Reducing Antioxidant Potential (FRAP)

The FRAP was determined according to the reported method [28] with some modifications. FRAP reagent was prepared by mixing 0.3 M acetate buffer (pH 3.6), 10 mM TPTZ, and ferric chloride with the appropriate proportion (10:1:1, v/v/v). The FRAP reagent (200 μL) was mixed with 20 μL of sample solution and the reaction system was incubated at 25 °C for 10 min. The Abs at 593 nm was then measured.