EFFECTS OF OLIVE LEAF EXTRACT ON LEARNING AND MEMORY IN STREPTOZOTOCIN-INDUCED DIABETIC RATS

Aim: To investigate the impact of olive leaf extract (OLE) on learning and memory performance in diabetic rats induced by streptozotocin (STZ), utilizing the Morris water maze (MWM) test. Methods: Thirty-two male Wistar albino rats were randomly assigned to four groups: Control (group 1), STZ-induced diabetes (group 2), STZ + OLE (group 3), OLE + STZ (group 4). The treatment groups (group 3,4) received 0.5 g/kg of OLE orally for six weeks. MWM test was conducted to evaluate latency to find the platform, total distance swum, and average speed. Hippocampal tissues were examined for measurement of enzyme activities (Malondialdehyde (MDA), Catalase (CAT), Superoxide Dismutase (SOD), and Glutathione Peroxidase (GPx). Blood glucose levels were recorded both at the before the study and before surgery. Results: Control and treatment groups exhibited shorter latencies to reach the platform, with the most significant reductions in Control group and OLE+STZ group. On Day 5, OLE + STZ group swam the shortest distance. A significant reduction in distance swam was found between Group 2 and treatment groups over time. Mean speed differences were significant only on Day 1 between groups. MDA levels were higher in group 2 compared to controls but MLA were reduced in treatment groups, particularly in OLE + STZ group. CAT levels were elevated in all groups relative to group 2. GPx and SOD levels were elevated in Control, OLE + STZ groups compared to group 2. OLE + STZ group's GPx and SOD levels were higher than STZ + OLE group. Blood glucose levels decreased in Control and treatment groups compared to the group 2, with the greatest reduction in OLE + STZ group. Discussion: OLE reduced oxidative stress and improved learning and memory in diabetic rats, with more pronounced effects observed in the group that received OLE before STZ administration.