Effect of Tinospora cordifolia on experimental diabetic neuropathy

OBJECTIVES: To evaluate the effect of aqueous extract of stem of Tinospora cordifolia (TC) on hyperalgesia in streptozotocin induced diabetic rats and in- vitro aldose reductase inhibition. MATERIALS AND METHODS: Wistar albino rats, rendered diabetic with streptozotocin, were divided into 5 groups, namely the diabetic control treated with vehicle (DC), standard control which received glibenclamide+metformin (SC), test groups treated with 100, 200and 400 mg/kg b.w. of Tinospora cordifolia (TC1, TC2 and TC3 respectively). A group of five normal animals served as normal control (NC). Fasting blood glucose, body weight and reaction time to tail flick were measured one week after induction of diabetes. The animals were then treated orally for two weeks after which the same parameters were repeated. In-vitro aldose reductase inhibition assay was carried out at concentrations of 5, 10, 25, 50, 100 and 200 mcg/ml of Tinospora cordifolia using rat lens from normal rats. The in-vivo results were analysed with Mann Whitney test. RESULTS: The DC group demonstrated a decrease in the reaction time (hyperalgesia) compared to NC while a significant increase in the reaction time was observed with SC, TC2 and TC3 groups (p<0.05) as compared to the DC group. TC1 and TC2 showed a significant reduction in body weight compared to their baseline values (p<0.05). There was no significant change in the fasting blood glucose (FBS) in any of the groups. In-vitro aldose reductase inhibition was observed with TC with an IC(50) of 103 mcg/ml. CONCLUSIONS: Tinospora cordifolia prevents the hyperalgesia in experimental diabetic neuropathy. It has an aldose reductase inhibitory activity in-vitro which may contribute to the beneficial effects.