ABSTRACT

The genus Olea L. (Oleaceae) is represented by 67 species in the world. Two varieties of Olea europaea L. (Olea europaea L. var. europaea and Olea europaea var. sylvestris (Miller) Lehr.) are growing in Turkey and are found mostly in the West and South Anatolia. In this study, antioxidant activity of the aqueous extracts obtained from the leaves and branches of O. europaea and oleuropein were investigated. The antioxidant activities were studied by two different techniques: Qualitative DPPH (1,1-diphenyl-2-picrylhydrazyl radical) assay to detect the free radical scavenging activity and the thiobarbituric acid (TBA)-assay to detect liposome lipid peroxidation. The lipid peroxidation was initiated in liposomes obtained from bovine brain extracts by addition of ascorbic acid and iron source and was measured spectrophotometrically with TBA test. The highest activity was observed with the extract of O. europaea var. sylvestris leaves with an IC50 value of 0.29 ug/ml where propil gallat (IC50=0.21±0.01) was used as the positive control.