Chebulagic acid attenuates HFD/streptozotocin induced impaired glucose metabolism and insulin resistance via up regulations of PPAR γ and GLUT 4 in type 2 diabetic rats.

The aim of the present study was to evaluate the effects of chebulagic acid on enzymes involved in carbohydrate metabolism in high-fat diet/streptozotocin-induced diabetic rats. Diabetes was induced in albino male Wistar rats by feeding them with a high-fat diet comprising of 84.3% standard laboratory rat chow, 5% lard, 10% yolk powder, 0.2% cholesterol, and 5% bile salt for 2 weeks. After 2 weeks, the animals were kept in an overnight fast and injected with a low dose of streptozotocin (35 mg/kg, dissolved in 0.1 M sodium citrate buffer, pH 4.5). At the end of the experimental periods, the blood glucose, plasma insulin, hemoglobin, glycated hemoglobin levels, homeostatic model of insulin resistance, glycogen content, glycogen synthase, glycogen phosphorylase were measured in high-fat diet and streptozotocin-induced diabetic rats whereas the glucose metabolic enzymes such as hexokinase, glucose 6 phosphate dehydrogenase, glucose 6 phosphatase, fructose 1,6 bisphosphatase and protein expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) and Glucose transporter 4 (GLUT4) were analyzed. Administration of chebulagic acid to HFD/STZ -induced diabetic rats for 30 days significantly decreased the levels of plasma glucose, homeostatic model assessment of insulin resistance, glycogen phosphorylase and glycosylated hemoglobin and increased the levels of insulin, glycogen content and glycogen synthase. On the other hand, the altered activity of carbohydrate metabolic enzymes, PPAR-γ and GLUT4 were brought back to near-normal levels on treatment with chebulagic acid. The effect produced by chebulagic acid on various parameters was comparable to that of metformin.

Antihyperglycemic Potential of Back Tea Extract Attenuates Tricarboxylic Acid Cycle Enzymes by Modulating Carbohydrate Metabolic Enzymes in Streptozotocin-Induced Diabetic Rats.

The present study was aimed to investigate the effect of black tea extract on blood glucose, plasma insulin, Hemoglobin, carbohydrate metabolic enzymes and tricarboxylic enzymes in streptozotocin (STZ) induced diabetic rats. Diabetes was induced in male albino Wistar rats by intraperitoneal administration of STZ (40 mg/kg b wt). Black tea extract was administered to diabetic rats at a dose of 25, 50 and 100 mg/kg body weight for 30 days. The effects of black tea extract on glucose, insulin and HbA1c levels were analyzed to confirm the effective dose. Administration of black tea extract to diabetic rats was significantly decreased the level of glucose, glycated hemoglobin and increased the levels of insulin in a dose dependent manner. The black tea extracts at a dose of 100 mg/kg b wt showed a highly significant effect compared to other two doses (25 and 50 mg/kg b wt). The effect produced by black tea extract (100 mg/kg b wt) was comparable to that of glibenclamide (5 mg/kg b wt) a reference anti diabetic drug. Therefore, 100 mg/kg b wt was fixed as an effective dose and used for further analyses. Black tea extract was administered to diabetic rats at a dose of 100 mg/kg b wt for 30 days reinstated the altered levels of the plasma glucose, insulin, hemoglobin, glycosylated hemoglobin, carbohydrate metabolizing enzymes and tricarboxylic cycle enzymes in diabetic rats. Black tea extract administered to diabetic rats at a dose of 100 mg/kg b wt for 30 days reinstated the altered levels of the plasma glucose, insulin, hemoglobin, glycosylated hemoglobin, carbohydrate metabolizing enzymes and tricarboxylic cycle enzymes in diabetic rats. The effect produced by black tea extract of all the biochemical parameters were comparable with glibenclamide-used as a reference drug.

Effect of ß-sitosterol on glucose homeostasis by sensitization of insulin resistance via enhanced protein expression of PPRγ and glucose transporter 4 in high fat diet and streptozotocin-induced diabetic rats.

ETHNOPHARMACOLOGICAL RELEVANCE: ß-Sitosterol is a plant derived compound similar to cholesterol structure and used in the treatment of hypercholesterolemia, prostate cancer, breast cancer and coronary artery disease. But no studies have been reported the effect of ß-sitosterol on glucose homeostasis by sensitization of insulin resistance via enhanced protein expression of peroxisome proliferator-activated receptor γ (PPARγ) and glucose transporter 4 (GLUT4) in insulin dependent tissues of high fat diet and streptozotocin-induced diabetic rats. MATERIALS AND METHODS: Type 2 diabetes was induced in male albino Wistar rats by feeding them with high fat diet comprising of 84.3% standard laboratory chow, 5% lard, 10% yolk powder, 0.2% cholesterol and 0.5% bile salt for 2 weeks. After 2 weeks, the animals were kept in an overnight fast and injected with low dose of streptozotocin (35 mg/kg, dissolved in 0.1 M sodium citrate buffer, pH 4.5). Analysis of blood glucose, insulin, hemoglobin and glycated hemoglobin were done by commercially available diagnostic kits. The PPARγ and GLUT4 were analyzed by western blotting using respective primary and secondary antibodies. RESULTS: Upon administration of ß-sitosterol at a dose of 15 mg/kg body weight per day to high fat diet and streptozotocin induced diabetic rats for 30 days significantly decreased the levels of plasma glucose, homeostatic model assessment of insulin resistance and glycosylated hemoglobin and increased the levels of insulin, hemoglobin and protein expression of PPARγ and GLUT4 in insulin dependent tissues. Furthermore, ß-sitosterol administration prevented the body weight loss and excessive intake of food and water. CONCLUSION: These finding suggest that ß-sitosterol can replace the commercial drugs which could lead to reduction in toxicity and side effect caused by the later as well as reduce the secondary complications.