The Effect of Olive Leaf Methanolic Extract on Hippocampal Antioxidant Biomarkers in an Animal Model of Parkinson’s Disease

Background and Objective: Parkinson’s disease (PD) is a chronic neurodegenerative disease characterized by damages to striatal dopaminergic neurons that affects 1 to 2% of the population above 65 years of age. Olive leaf extract (OLE) is a powerful antioxidant that is considered as a source of various phenolic compounds. This study was conducted to evaluate the effects of methanolic OLE on hippocampal antioxidant biomarkers in an animal model of PD. Materials and Methods: Intrastriatal 6-hydroxydopamine-lesioned rats were pretreated with OLE at doses of 50, 100 and 150 mg/kg/day for six weeks. At the end of treatment, the antioxidants activity in the hippocampal area was assayed. Results: 6-hydroxydopamine–induced oxidative stress significantly decreased activity of superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione reductase (GRX) and catalase (CAT) and treatment with OLE restored the activity of antioxidant enzymes SOD, GPX, GRX, and CAT and also decreased malondialdehyde (MDA) as an index of lipid peroxidation and increased glutathione (GSH) levels in the hippocampus. Conclusion: These results suggest that OLE pretreatment reduces hippocampal oxidative biomarkers in an animal model of PD.