2.3.4. Ferric Reducing Antioxidant Power (FRAP) Assay

A FRAP assay was used to further elucidate the antioxidant efficiency of the prepared extracts. In this procedure, the required concentration of acetate buffer, TPTZ (2,4,6-tris(2-pyridyl)-s-triazine) in diluted hydrochloric acid, and ferric chloride hexahydrate were prepared as stock solutions. The 25 mL of acetate buffer, 2.5 mL of TPTZ, and the ferric chloride hexahydrate solutions were then mixed and retained at 37 °C to prepare the working solution. The C. asiatica leaf extracts were dissolved in MeOH and mixed with the Trolox methanolic solution, which was employed as a control. To the test tube holding 2.9 mL of the working solution, 10 μL of MeOH extract solution was added. After that, for 30 min without light, these samples were allowed to interact with one another. The absorbance values were obtained at 593 nm wavelength. Through the use of a standard curve created for varied Trolox concentrations, the FRAP data were translated to micromoles of Trolox equivalents.