ABSTRACT

 This study investigated the invitro antioxidant activity of ethylacatate extract of oven dried citrus sinensis peels. The orange peels were oven dried (55°C) and subsequently subjected to extraction with ethylacetate. The phenolic content of the sample was studied according to the method described by Folic-Ciocalteu. Whereas the total flavonoid content was studied according to the aluminium chloride method. In vitro antioxidant activity of the oven dried peel were assessed using three different methods DPPH (l,l-diphenyl-2-picry!hhydrazyl) scavenging activity, reducing power and hydrogen peroxide percentage inhibition). The results show that the ferric reducing antioxidant power (FRAP), 1,1-diphenyl-2-picrylhhydrazyl (DPPH) scavenging activity and hydrogen peroxide (H2O2) inhibitionof the plant extract increased with increasing extract concentrations. Also, the results showed that the FRAP, DPPH and ^Chofthe plant extract was significantly (p < 0.05) low when compared to ascorbic acid at all concentrations tested. At the highest concentration (0.1 mg/ml), the percentage DPPH inhibition ofthe plant extract was 81.61 ± O.Olmg/ml as compared to vitamin C (104.72 ± 0.02 mg/ml), the ferric reducing power assay ofthe plant extract was 71.41 ± 0.03 mg/ml as compared to vitamin C (79.43 ± 0.02 mg/ml) and the percentage hydrogen peroxide inhibition of the plant extract was 64.15 ± 0.02 mg/ml as compared to vitamin C (88.42 ± 0.02 mg/ml). The values ofthe total phenol and total flavonoid were 14.65 ± 0.04 mg/ml and 6.34 ± 0.01 mg/ml respectively. This study affirms the invitro antioxidant potential of the ethylacetate extract of oven dried orange peel with results comparable to known antioxidant compounds such as vitamin C and gallic acid thus, the plant extract can be used as antioxidant supplements or additives.