Comparative Analysis of Antioxidant Activities of Matoa (Pometia pinnata) Peel Extracts Using DPPH, ABTS, and FRAP Assays

Abstract

The fruit peel of matoa (Pometiapinnata), commonly discarded as waste, is known to contain bioactive compounds with high antioxidant potential. This study aims to compare the antioxidant activity of P. pinnata fruit peel extracts using solvents of varying polarity (ethanol, n-butanol, and ethyl acetate) and assays (DPPH, ABTS, and FRAP). IC50 values were calculated using a four-parameter logistic model, and FRAP values were reported as mg GAE/g of extract. Phytochemical screening revealed that the ethanolic extract (ETM) contained the most diverse secondary metabolites, including phenolics, flavonoids, tannins, terpenoids, and triterpenoids. The DPPH assay showed the highest antioxidant capacity in ETM (IC50 = 44.90 ppm), followed by ethyl acetate (EAM, 95.66 ppm) and n-butanol (NBM, 397.80 ppm). In the ABTS assay, ETM and EAM demonstrated weaker activities (IC50 = 3424 ppm and 13,485 ppm, respectively), while NBM showed no significant activity. The FRAP results indicated that ETM exhibited the strongest reducing power (6.26 ± 0.08 mg GAE/g), followed by EAM (5.44 ± 0.07 mg GAE/g) and NBM (0.77 ± 0.03 mg GAE/g). Solvent polarity influences antioxidant activity and bioactive composition, and ethanol is the most effective solvent for extracting antioxidant compounds from matoa peel.