Antimicrobial, antioxidant and anti-EBV activities of olive leaf (Olea Europea) extracts from Tunisia

Abstract Background: Olive tree leaves ( Olea europaea ) are widely used in traditional medicine in the Mediterranean Region. Interest in the olive leaf and its chemical constituents has recently been increasing. Its benefits, however, have been known for centuries, and it has been traditionally used to prevent and treat different diseases. The aim of this study was the determination of antimicrobial, antioxidant activities and anti-EBV effects of olive leaves. Methods : The present study was focused on extraction of leaves of olea europea cultivated and wild type from two different geographical tunisian zone: Sfax and El Kef, and the determination of antimicrobial activities against Gram- and Gram+ bacteria and fungi. Olive leaves was analyzed for antioxidant power in chemical system by the DPPH test and the chemiluminescence and in biological system by lipid peroxydation tests (MDA and DC) in Raji cells lines. The antiviral (anti-EBV) effects of olive leaves were assessed using indirect immunofluorescence technique. Results: The antioxidant effect was studied by chemiluminescence where a significant decrease on reactive oxygen species production was observed after leaves olive extract treatment. Antioxidant activities were studied by direct reactive oxyden species assay using chemical systems. The results very interesting for both wild type and cultivated in the two regions since we obtained IC50s of the order of 20.79 μg / ml (cultivated sfax) with DPPH scavening radical. The best result obtained when used olive leaves extract cultivated from Sfax. Our results showed a protection against oxidative stress, highlighted by a significant decrease in MDA and DC levels (p <0.05). Also, a significant antiviral effect of leaves of olive cultivated in Sfax against Epstein-Barr virus (EBV) was determined. Conclusion: The olive leaves extracts analyzed in this work showed a potent antimicrobial activity, an antioxidant activity was expressed by a significant decrease in the production of ERO in the Raji cell line and an anti-EBV effect.