Olea ferrugenia : A potential natural source of protection from oxidative stress

The methanolic extract of Oleaferrugenia Royale was dissolved in distilled water and partitioned with nhexane, chloroform, ethyl acetate and n-butanolsuccessively. The phytochemical screening of all these organic fractionsand remaining aqueous fractionwas carried out and then the antioxidant potential of all studied fractionswas evaluated by four in vitro methods: DPPH free radical scavenging activity, total antioxidant activity, FRAP assay and ferric thiocyanate assay. Total phenolics of these organic fractionswere also determined. All the fractionsshowed significant antioxidant potential. The results revealed that ethyl acetate soluble fractionshowed highest value of percentage inhibition of DPPH radical (92.96% ± 0.13), with IC50 value of (19.76 ± 0.12 μg/ml, relative to butylated hydroxytoluene(BHT), having IC50 of 12.1 ± 0.92 μg/mL. This fractionalso exhibited highest FRAP value (714.45 ± 2.61 μg of troloxequivalents), highest total phenolic contents (416.4.59 ± 7.73 mg of gallic acidequivalents), as well as highest value of inhibition of lipid peroxidation (57.51% ± 1.56) when compared with other fractions. However, the chloroform soluble fractionshowed highest total antioxidant activity (0.9101 ± 0.03) when compared with other fractions.