The effect of Nepeta menthoides aerial parts hydroalcoholic extract on learning and memory in male streptozotocin-induced diabetic rat

Background and Objective: Diabetes mellitus is a common metabolic disorder that causes undesirable effects including learning and memory impairment. It has been reported that Nepeta menthoides improves memory and learning. Therefore, the aim of this study was to evaluate the effects of Nepeta menthoides on learning and memory impairment related to diabetes in rats.   Materials and Methods: Forty male rats were divided into 4 groups including control, diabetic control, control group under treatment with extract of Nepeta menthoides, and diabetic group under treatment with extract of Nepeta menthoides. A single dose of streptozotocin intraperitoneally was used for diabetes induction in diabetic animals. After 6 weeks, Nepeta menthoides treatment was performed as an intraperitoneal injection of 400 mg/kg/day for two weeks, 30 min before each behavioral test. The eight-arm radial maze method with two-way repeated measures ANOVA test were used to evaluate learning and memory and one-way ANOVA was used for comparing blood glucose between different groups.   Results: Diabetes caused learning and memory impairment in the form of increasing working and reference memory errors and use of Nepeta menthoides extract in the diabetic rats caused a significant reduction in the number of related errors. Nepeta menthoides also declined blood glucose in diabetic rats.   Conclusion: Nepeta menthoides consumption in diabetic rats improves diabetes-induced learning and memory impairment. This effect might be mediated at least partly by decreasing blood glucose.