Antioxidant activities and phenolic composition of Olive (<i>Olea europaea</i>) leaves

Abstract

The present study compares the antioxidant activities of leaves of eight cultivars of olive. The aqueous extracts of leaves showed inhibition against thiobarbituric acid reactive species (TBARS) induced by pro-oxidant (10 µM FeSO4) in mice liver. The order of the antioxidant activity among cultivars on lipid peroxidation assay is Gemlik > Frantio > Doleca-Agogia > Moriolo > Mission > Uslu > Leccino > Carotina. Different varieties of olive showed good antioxidant properties, IC50 values ranged between22.46 to 198 µg/ml on 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The major phenolic acids, some flavonoid aglycone and glycosides were identified in leaves by high performance liquid chromatography. Ellagic acid (29.80 ± 0.02 mg/g), caffeic acid (15.73 ± 0.01mg/g), gallic acid (15.69 ± 0.01 mg/g), rutin (34.56 ± 0.03 mg/g), quercetin (16.41 ± 0.01 mg/g), epicatechin (11.04 ± 0.01 11.04 ± 0.01 mg/g) and quercetrin (15.32 ± 0.03 mg/g) were predominant in infusion of olive.