Evaluation of the extraction hours and solvent concentrations on secondary metabolites and antioxidant activity of Feronia limonia fruit

The study was performed to compare the effect of different solvents and extraction hours on secondary metabolites and antioxidant activity of the unripe fruit of Feronia limonia. The investigation was achieved by using two extraction hours (24 and 48 h). Secondary metabolites of unripe fruit of F. limonia were extracted in different solvents viz., distilled water, ethanol, methanol, and acetone at 60, 80, and 100% concentrations. Qualitative followed by quantitative analysis of the phytochemical constituents of the fruit was done. Antioxidant activities of the fruit were studied through DPPH free radical scavenging activity, ferric reducing antioxidant power, metal chelating activity, and reducing capacity. The result indicates that 48 h of extraction is more effective for extraction of bioactive compounds than 24 h extraction. The qualitative analysis of phytochemical constitutes indicated the presence of phenols, flavonoids, alkaloids, saponins, and tannins. The highest phenolic content (44.00 mg GAE/g) and DPPH activity were obtained in 60% aqueous acetone while the highest flavonoids content (35.25 mg QCE/g), ferric reducing antioxidant power, metal chelating activity, and reducing capacity were obtained in 100% methanol extract. This study confirmed that the antioxidant activity of unripe F. limonia fruit is attributed to both flavonoid and phenols by employing multiple linear regressions. The unripe fruit contains several secondary metabolites and antioxidant activities which could be used to reduce oxidative stress