Herbal Anti-Hyperglycemic Compound Increases Expression of Glucose Transporter Molecules in Diabetic Rats

Background: In previous studies, Sharma et al. has already isolated an anti-hyperglycemic compound from the fruit pulp of Eugenia jambolana using HPLC and other chromatographic techniques. However, the effect of antihyperglycemic compound (FIIc) on the expression of Glucose transporters and Kv 1.3 potassium channel in Streptozotocin-Nicotinamide induced diabetic rats has not been studied so far. Objective: To study the effect of HPLC purified herbal anti-hyperglycemic compound (FIIc) on the expression of GLUT-4, GLUT-8 and Kv 1.3 potassium channel in Streptozotocin-Nicotinamide induced diabetic rats. Methods: 24 Male Wistar rats were taken and diabetes was induced in group B, C and D rats (n=6 each) by injecting Streptozotocin at a dose of 45 mg/kg of body weight 15 minutes after the administration of Nicotinamide at a dose of 230 mg/kg of body weight, intra-peritoneally to overnight fasted rats. Active compound (FIIc) was orally administered to group C and Pioglitazone to group D at a dose of 20 mg/kg of body weight for 6 weeks respectively. Serum was separated for the estimation of Adiponectin and TNF alpha at week 0 and week 6 of the study. Real time mRNA expression of GLUT-4, GLUT-8 and Kv 1.3 potassium channel was measured and compared between healthy and diabetic control rats. Expression of GLUT-4, GLUT-8 and Kv 1.3 potassium channel was also measured at protein level through Immunohistochemistry and compared between healthy and diabetic controls. Results: After treatment with FIIc for 6 weeks there was a 1.28 folds increase in GLUT-4 mRNA expression in skeletal muscles and 2.67 folds increase in GLUT-8 mRNA expression in liver tissues of group C rats as compared to group B rats. However, Kv 1.3 potassium channel mRNA expression was found to be at par among the four study groups. TNF alpha levels were found to be significantly decreased in group C rats as compared to group B. A slight increase in serum Adiponectin level was observed in group C as compared to group B, which was found to be statistically insignificant. Conclusion: FIIc treatment for 6 weeks significantly increases the expression of GLUT-4, GLUT-8 mRNA expression in liver and skeletal muscles leading to increased peripheral insulin sensitivity.