Effect of Oleuropein Extract from Olive on Brain Oxidative Stress in Ovariectomized Diabetic Rats

Background and objectives: Increased oxidative stress and altered antioxidant levels play an essential role in the pathogenesis of diabetes mellitus. Menopause is associated with increased food intake, weight gain, metabolic disorders, and increased level of inflammatory and oxidative stress factors. This study evaluated effects of oleuropein extract on brain tissue and serum oxidative status in ovariectomized diabetic rats. Methods: In this study, 40 female Wistar rats weighing 250±20 grams were randomly divided into four groups: control, sham (surgery without ovariectomy), ovariectomy+diabetes, and ovariectomy+diabetes+oleuropein supplementation. Diabetes was induced by intraperitoneal injection of streptozotocin. The rats in the treatment group received 60 mg/kg of oleuropein for 30 days by oral gavage. Finally, blood glucose, superoxide dismutase, glutathione peroxidase, total antioxidant capacity, and malonaldehyde levels were evaluated in serum and brain tissue samples. Results: Weight, blood glucose level, and antioxidant enzymes activity increased significantly in the ovariectomy+diabetes group compared to the control group. Conclusion: This study suggested that the administration of oleuropein extract has beneficial effects on blood glucose level and antioxidant status in serum and brain tissue of ovariectomized diabetic rats.