Tarique Anwer

Effect of Withania somnifera on Insulin Sensitivity in Non‐Insulin‐Dependent Diabetes Mellitus Rats

We investigated the effect of an aqueous extract of Withania somnifera (WS) on insulin sensitivity in non-insulin-dependent diabetes mellitus (NIDDM) rats. NIDDM was induced by single intraperitoneal injection of streptozotocin (100 mg/kg) to 2 days old rat pups. WS (200 and 400 mg/kg) was administered orally once a day for 5 weeks after the animals were confirmed diabetic (i.e. 75 days after streptozotocin injection). A group of citrate control rats (group I) were also maintained that has received citrate buffer on the second day of their birth. A significant increase in blood glucose, glycosylated haemoglobin (HbA(1)c) and serum insulin levels were observed in NIDDM control rats. Treatment with WS reduced the elevated levels of blood glucose, HbA(1)c and insulin in the NIDDM rats. An oral glucose tolerance test was also performed in the same groups, in which we found a significant improvement in glucose tolerance in the rats treated with WS. The insulin sensitivity was assessed for both peripheral insulin resistance and hepatic insulin resistance. WS treatment significantly improved insulin sensitivity index (K(ITT)) that was significantly decreased in NIDDM control rats. There was significant rise in homeostasis model assessment of insulin resistance (HOMA-R) in NIDDM control rats whereas WS treatment significantly prevented the rise in HOMA-R in NIDDM-treated rats. Our data suggest that aqueous extract of WS normalizes hyperglycemia in NIDDM rats by improving insulin sensitivity.

Silymarin, a flavonoid antioxidant, protects streptozotocin-induced lipid peroxidation and β-Cell damage in rat pancreas

The present study is aimed at finding the influence of silymarin (a flavonoid) (25 mg/kg & 50 mg/kg) in streptozotocin (STZ)-induced diabetic rats. Type 2 diabetes was induced by single intraperitoneal injection of STZ (100 mg/kg) to 3 days old rat pups. Silymarin was administered for 15 days after the animals were confirmed diabetic (75 days after STZ injection). Blood glucose, glycosylated hemoglobin (HbA1c), lipid peroxides (LPO) levels and reduced glutathione (GSH) contents in pancreas and liver were estimated following the established procedures. Biochemical observations were further substantiated with histological examination of pancreas. Blood glucose and HbA1c levels, which were elevated by STZ, were lowered to physiological levels by the administration of silymarin. The levels of LPO were significantly increased in STZ-induced diabetic rats. Silymarin reduced the LPO levels in both pancreas and liver. GSH contents which were reduced significantly in pancreas and liver of STZ-induced diabetic rats were brought back to near normal levels by silymarin treatment. Multifocal necrotic and degenerative changes of pancreas in STZ-diabetic rats were minimized to near normal morphology by administration of silymarin as evident by histopathological examination. Silymarin showed a dose dependent protective effect on STZ-induced β-cell damage. It could be attributed to the antioxidative and free radicals scavenging properties of the flavonoid. Thus, it may be considered as a natural antioxidant with potential therapeutic application in the treatment of type 2 diabetes.

Antidiabetic activity of seed extracts of Caesalpinia crista Linn. in experimental animals

The present study was designed to evaluate antidiabetic activity of ethanolic and aqueous seed extracts of Caesalpinia crista linn. in streptozotocin (STZ) induced diabetes in 2 days old pups models. The seeds were collected, authenticated and shade dried. Shade dried seeds were then grinded into coarse powder and processed for further studies. Ethanolic and aqueous extracts were prepared and the preliminary phytochemical screening was performed. Ethanolic and aqueous both extracts were evaluated for the antidiabetic activity by using the streptozotocin induced diabetes in 2 days old pups model. After 3 months of streptozotocin administration, pups become diabetic and then further protocol was proceeded. Estimation of biological parameters like serum glucose, cholesterol and triglyceride were performed and body weight, water intake and food intake were also recorded after 3 weeks of treatment. Histopathological study was performed to study the structure of islets of pancreas in different group of animals. There was a significant decrease in the biological parameters that is, serum glucose, cholesterol and triglyceride when compared with diabetic untreated group after 3 weeks treatment plant extracts. Treatment with the extracts also affected the physical parameters like decrease in body weight, increase in demand of food intake and water intake when compared with diabetic untreated group. Histopathological study shows the changes in structure of islets of pancreas in different groups of animals. Hence, it can be concluded that in the above study, both ethanolic and aqueous seed extracts of C. crista linn. showed antidiabetic activity, but the aqueous extract of C. crista linn. showed more significant effect as compared to the ethanolic extract.

Antihyperglycemic, antidyslipidemic and antioxidant activity of Rhus coriaria in STZ-induced type 2 diabetic rats

The potential role of methanolic extract of Rhus coriaria L. on hyperglycemia, dyslipidemia and lipid peroxidation (LPO) was studied in type 2 diabetic rats. Type 2 diabetes was induced by a single intraperitoneal injection of streptozotocin (STZ, 100 mg/kg) to 2 days old rat pups. R. coriaria (200 and 400 mg/kg) was administered orally once a day for 5 weeks after the animals were confirmed diabetic (that is, 90 days after STZ injection). A group of citrate control rats were also maintained which has received citrate buffer on the 2 nd day of their birth. Administration of R. coriaria extract showed a significant (P < 0.001) decrease in blood glucose and tissue MDA levels as compared to type 2 diabetic control rats. The levels of total cholesterol (TCh), triglycerides (TG), low density lipoprotein cholesterol (LDL-C) and very low density lipoproteins cholesterol VLDL-C were also significantly (P < 0.001) decreased by R. coriaria treatment when compared with type 2 diabetic control rats. In contrast the high density lipoprotein cholesterol (HDL-C) levels were significantly (P < 0.001) increased after treatment with R. coriaria extract when compared with type 2 diabetic control rats. These results revealed that R. coriaria possesses significant antihyperglycemic and antidyslipidemic activity along with potent antioxidant potential in type 2 diabetic mellitus.

Protective effect of silymarin in streptozotocin-induced diabetic dyslipidaemia in rats

The present study investigated the effect of silymarin, a flavonoid, on streptozotocin (STZ) - induced diabetic dyslipidaemia in rats. Experimental diabetes was induced by a single intraperitoneal injection of STZ (60 mg/kg). Silymarin (25 mg/kg and 50 mg/kg) was orally administered to diabetic rats for a period of 15 days. Blood glucose levels, serum lipid profile and liver glycogen levels were estimated following the established procedures. Biochemical observations were supplemented with histological examination of liver sections. Oral administration of silymarin to diabetic rats significantly (P vs. [25 mg] & [50 mg]). The most interesting finding was the significant (p vs. [25 mg] & [50 mg]) whereas, there was a significant decrease in serum total cholesterol (TCh), triglycerides (TG), low density lipoprotein (LDL) and very low density lipoprotein (VLDL) cholesterol levels observed in silymarin treated diabetic rats. STZ treatment caused significant degeneration of liver parenchyma, which was normalized to near normal morphology by administration of silymarin. The findings indicate that silymarin effectively improved the overall lipid profile and restored the glycogen stores in the liver of STZ-induced diabetic rats, in a dose dependent manner. The results indicate existence of abnormalities in lipid metabolism in STZ-induced diabetic rats and suggest a protective effect of silymarin in this animal model.