Background: Diabetes causes cognitive impairment. Medicinal plants due to different mechanisms, such as antioxidant activities may improve diabetes and relieve its symptoms. Commiphora mukul (Burseraceae) has a significant antioxidant activity.
Objectives: This study aimed to examine the effect of hydro- alcoholic extract of C. mukul on passive-avoidance learning and memory in streptozotocin (STZ) induced diabetic male rats.
Materials and Methods: Thirty-two adult male Wistar rats were randomly allocated to four groups: normal, diabetic, normal + extract of C. mukul and diabetic + extract of C. mukul groups with free access to regular rat diet. Diabetes was induced in male rats by single interaperitoneal injection of 60 mg/kg STZ. After the confirmation of diabetes, 300 mg/kg C. mukul extract was orally administered to the extract-treated groups. Control groups received normal saline at the same time. Passive-avoidance memory was tested eight weeks after the STZ treatment, and blood glucose and body weight were measured in all groups at the beginning and end of the experiment.
Results: In the present study, diabetes decreased learning and memory. Although the administration of C. mukul extract did not affect the step-through latency (STLa) and the number of trials of the diabetic groups during the first acquisition trial, a significant decrease was observed in STLr and also a significant increase in time spent in the dark compartment (TDC) and number of crossing (NOC) in the retention test (after 24 and 48 hours). Although no significant difference was observed in body weight of diabetic + extract of C. mukul (DE) and diabetic control (DC) groups, the plasma glucose of DE group was significantly lower in comparison to DC group.
Conclusions: Commiphora mukul extract can improve passive-avoidance learning and memory impairments in the STZ-induced diabetic rats. This improvement may be due to the antioxidant, acetylcholinesterase inhibitory activity, anti-inflammatory or power to reduce hyperglycemia and lowering cholesterol and triglyceride properties of this extract. The result of this study is a promising point for new therapeutic alternatives in alleviating cognitive impairments caused by diabetes.