Evaluation of biochemical mechanisms of anti-diabetic functions of Anisomeles malabarica.

Anisomeles malabarica (AM) is an aromatic plant traditionally used for the treatment of diabetes mellitus in India. Following bioassay guided fractionation, we recently identified an active fraction of AM (AMAF, with potential mix of active principles) that showed significant antihyperglycemic and antihyperlipidemic activities. In addition, AMAF treatment improved insulin levels. However, the biochemical mechanism/s through which AMAF demonstrates the antidiabetic effects is largely unknown. Based on its beneficial effects we investigated the biochemical mechanism of the anti-diabetic activity of A.malabarica active fraction (AMAF) in streptozotocin (STZ) induced diabetic rats. Streptozotocin induced diabetic rats were treated with AMAF (50 mg AMAF/kg/day) for 30 days and alterations in the body weights, glycogen and protein content of tissues, functional markers of hepatic and renal tissues, carbohydrate metabolic enzymes and their genes expression were evaluated. Lipid peroxides levels and activities of antioxidant enzymes of hepatic and renal tissues were also measured. The AMAF treatment resulted in increase in body weights, hepatic and renal protein and tissue glycogen levels in diabetic treated rats compared to diabetic rats. In addition, the treatment improved activities of carbohydrate metabolic enzymes, antioxidant enzymes and, liver and renal functional markers in the AMAF treated diabetic rats. Gene expressions of key carbohydrate metabolic enzymes/factors glucokinase, glucose transporter protein (GLUT-2) and phosphoenolpyruvate carboxykinase (PEPCK) were also normalized up on AMAF treatment in diabetic rats. Our studies indicate that the isolated active fraction of AM (AMAF) from the leaves of A.malabarica positively regulated the glucose homeostasis and oxidative stress through carbohydrate metabolism and antioxidant enzyme activities respectively in hepatic and renal tissues.