Evaluation of anti-diabetic effect of Trigonella foenum graecum Linn. Leaf extract in streptozotocin induced diabetic rats

Influence of rutin and its combination with metformin on vascular functions in type 1 diabetes

The present work examined the effect of oral administration of rutin and its combination with metformin, an antidiabetic drug on blood glucose, total cholesterol and triglycerides level and vascular function in streptozotocin (STZ) -induced diabetic rats. Male Sprague Dawley rats were rendered diabetic by a single intraperitoneal injection of STZ (50 mg/kg). Rutin and metformin were orally administered to diabetic rats at a dose of 100 mg/kg and 300 mg/kg body weight/day, respectively, for 4 weeks. Plasma analysis was conducted to determine changes in the plasma glucose and lipid levels. Rat aortic ring reactivity in response to endothelium-dependent (acetylcholine, ACh) and endothelium-independent (sodium nitroprusside, SNP) relaxants, and to the α1-adrenergic agonist phenylephrine (PE) were recorded. Histology of pancreas, liver and kidney were evaluated. In results, rutin and metformin alone and in combination has led to significant improvements in blood glucose, cholesterol and triglyceride levels compared to diabetic group. Diabetic aortic rings showed significantly greater contraction in response to PE, and less relaxation in response to ACh and SNP. Treatment with rutin and metformin in combination significantly reduced PE-induced contraction and increased ACh-induced and SNP-induced relaxation in diabetes when compared to rutin or metformin alone. Significant histological improvements were seen with combination therapy. In conclusion, rutin and metformin combination therapy has the most potentiality for restoring blood glucose and lipid level as well as vascular function.

Modulatory effect of garcinol in streptozotocin-induced diabetic Wistar rats

The objective of the study was to evaluate the efficacy of garcinol as an antidiabetic candidate in streptozotocin-induced diabetic Wistar rats. Diabetic rats showed a significant increase in the biochemical parameters such as fasting blood glucose, glycated haemoglobin, urea, alanine aminotransferase and aspartate aminotransferase, malondialdehyde, total cholesterol, triglycerides, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, atherogenic index and a significant decrease in plasma insulin, HOMA-β-cell functioning index, glycogen, high-density lipoprotein cholesterol, body weight and antioxidant enzyme activities, viz. superoxide dismutase, catalase and reduced glutathione. Oral administration of garcinol (10 and 20 mg/kg body weight/day) for 30 days improved the above-mentioned alterations. The effect produced by the drug was compared with that of glibenclamide, a standard hypoglycaemic drug. These findings reveal that garcinol can be a promising antidiabetic candidate in the future.

Protective Action of Carica papaya on β-Cells in Streptozotocin-Induced Diabetic Rats

The aim of the present study was to investigate the effect of C. papaya L. leaf extract (CPLE) on pancreatic islets in streptozotocin (STZ)-induced diabetic rats, as well as on cultured normal pancreatic cells with STZ in the medium. CPLE (3–125 mg/Kg) was administered orally for 20 days, while a group of diabetic rats received 5 IU/Kg/day of insulin. At the end of the treatment the rats were sacrificed. Blood was obtained to assess glucose and insulin levels. The pancreas was dissected to evaluate β cells by immunohistochemistry. In addition, normal pancreatic cells were cultured in a medium that included CPLE (3–12 mg). One half of the cultured cells received simultaneously CPLE and STZ (6 mg), while the other half received CPLE and five days later the STZ. After three days of incubation, insulin was assayed in the incubation medium. The CPLE administered to diabetic rats improved the fasting glycemia and preserved the number and structure of pancreatic islets. However, when CPLE was added to pancreatic cells in culture along with STZ, the insulin concentration was higher in comparison with the cells that only received STZ. In conclusion, the CPLE preserves the integrity of pancreatic islets, improves the basal insulin secretion and protects cultured cells from the adverse effects of STZ.

Antihyperlipidemic effect of a polyherbal mixture in streptozotocin-induced diabetic rats

The effects of a polyherbal mixture containing Allium sativum, Cinnamomum zeylanicum, Citrullus colocynthis, Juglans regia, Nigella sativa, Olea europaea, Punica granatum, Salvia officinalis, Teucrium polium, Trigonella foenum, Urtica dioica, and Vaccinium arctostaphylos were tested on biochemical parameters in diabetic rats. The animals were randomized into three groups: (1) normal control, (2) diabetic control, and (3) diabetic rats which received diet containing 15% (w/w) of this mixture for 4 weeks. Diabetes was induced by intraperitoneal injection of streptozotocin (55 mg/kg). At the end of experiment, the mixture had no significant effect on serum hepatic enzymes, aspartate aminotransferase, and alanine aminotransferase activities. However, the level of fasting blood glucose, water intake, and urine output in treated group was lower than that in diabetic control rats (P < 0.01). Also, the levels of triglyceride and total cholesterol in polyherbal mixture treated rats were significantly lower than those in diabetic control group (P < 0.05). Our results demonstrated that this polyherbal mixture has beneficial effects on blood glucose and lipid profile and it has the potential to be used as a dietary supplement for the management of diabetes.