Antidiabetic activity of Naregamia alata in streptozotocin induced diabetic rats and associated mechanism of action

Background

Diabetes mellitus type 2 is a common metabolic disorder characterized by an impaired insulin release, an insulin resistance followed by an altered metabolism. The use of plant based antidiabetic drugs attains an increased importance in recent days due to their potentially reduced side effects. Naregamia alata Wight & Arn. is a small plant extensively referred in Indian traditional medicine to treat various diseases including diabetes.

Aim

Evaluation of the antidiabetic activity of the methanolic extract (ME) and fractions (petroleum ether (PE), dichloromethane (DCM) and residual methanol (RM)) of N. alata.

Methods

Determination of the blood glucose, body weight and biochemical parameters (serum) in addition to the evaluation of the free radical generation, liver glycogen content and regeneration of pancreatic β-islets. An attempt was also made to investigate the major classes of phytochemicals responsible for the antidiabetic activity of N. alata.

Results

The dichloromethane fraction of N. alata showed a significant hypoglycemic effect along with improvements in the body weight (P < 0.01) and biochemical parameters (Serum protein, urea, creatinine, total cholesterol (TC), triglycerides (TG), high density lipoprotein-cholesterol (HDL-C), low density lipoprotein (LDL), very low density lipoprotein (VLDL)). Increased liver glycogen content and a reversal of serum and liver antioxidant levels in diabetic rats treated with the dichloromethane fraction were seen. The histopathological studies showed an improvement in the architecture of kidney and liver and a regeneration of pancreatic islets. The first phytochemical analyses revealed the presence of a significantly high amount of terpenes in the dichloromethane fraction of N. alata.

Conclusion

N. alata extracts showed hypoglycemic effect in STZ induced diabetic rats. Further studies to isolate the potent antidiabetic compound(s) and to identify synergistic, antagonistic or additive effects of the active ingredients are under progress.