Introduction & Objective: Diabetes mellitus (especially type I) is accompanied with disturbances in learning, memory, and cognitive skills in the human society and experimental animals. Considering the potential anti-diabetic effect of the medicinal plant Withania somnifera (ashwagandha) and the augmenting effect of its consumption on the memory and mental health, this study was conducted to evaluate the effect of chronic oral administration of ashwagandha root on learning and memory in diabetic rats using passive avoidance test.

Materials & Methods: For this purpose, male Wistar diabetic rats were randomly divided into control, ashwagandha-treated control, diabetic, and ashwagandha-treated diabetic groups. Ashwagandha treatment continued for 1 to 2 months. For induction of diabetes, streptozotocin was injected i.p. at a single dose of 60 mg/kg. Serum glucose level was determined before the study and at 4^th and 8^th weeks after the experiment. In addition, for evaluation of learning and memory, initial latency (IL) and step-through latency (STL) were determined after 1 and 2 months using passive avoidance test.

Results: It was found that one- and two-month administration of ashwagandha root at a weight ratio of 1/15 has not any significant hypoglycemic effect in treated control and diabetic groups. Furthermore, there was a significant increase (p<0.05) in IL in diabetic and ashwagandha-treated diabetic groups after two months compared to control group. In this respect, there was no significant difference between diabetic and ashwagandha-treated diabetic groups. In addition, STL significantly increased in ashwagandha-treated control group after 1 (p<0.01) and 2 (p<0.05) month in comparison to control group. On the other hand, STL significantly decreased (p<0.05) in diabetic group and significantly increased (p<0.05) in ashwagandha-treated diabetic group as compared to control group after two months.

Conclusion: In summary, chronic oral administration of ashwagandha root could enhance the consolidation and recall capability of stored information in control and diabetic animals.