COMPARATIVE IN VITROANTIOXIDANT EVALUATION OF CITRUS SINENSIS PEEL EXTRACTS USING DIFFERENT SOLVENTS

Abstract

The study aimed to evaluate the antioxidant activity ofCitrus sinensis (orange) peel extracts using different solvents - methanol, ethanol, water, acetone, chloroform, and benzene - highlighting the potential of citrus peel as a valuable agro-waste resource. The highest extraction yield was observed with methanol (16.5%), followed by ethanol (14.8%) and water (12.2%). Antioxidant capacity was assessed using DPPH, ABTS, reducing power, nitric oxide, and hydroxyl radical scavenging assays. The methanolic extract demonstrated the strongest radical scavenging activity across all assays. In the DPPH assay, methanol showed 84.32% inhibition at 300 µg/mL with the lowest IC₅₀ of 52.12 µg/mL, while ethanol and water exhibited 79.45% and 70.23% inhibition, respectively. In the ABTS assay, methanol achieved 78.31% inhibition (IC₅₀: 54.67 µg/mL). The reducing power of methanol extract increased from 0.412 at 25 µg/mL to 1.203 at 300 µg/mL, indicating strong electron-donating ability. In the nitric oxide scavenging assay, methanol extract showed 70.26% inhibition (IC₅₀: 58.34 µg/mL), while in the hydroxyl radical assay, it recorded 66.87% scavenging activity (IC₅₀: 61.78 µg/mL). These results suggest that methanol is the most effective solvent for extracting antioxidant compounds from Citrus sinensis peel. The study supports the sustainable utilization of citrus peel waste as a natural antioxidant source and encourages further research into compound identification, in vivo validation, and green extraction techniques for industrial application.