Modulatory effect of vanillic acid on antioxidant status in high fat diet-induced changes in diabetic hypertensive rats

The worldwide incidence of diabetes has increased dramatically along with widespread lifestyle and dietary changes. Diets high in fat are strongly associated with the development of obesity and can induce insulin resistance in humans and animals. It is clear that obesity constitutes a risk factor for contributing to the development of type 2 diabetes. In the present study, we investigated the therapeutic potential action of vanillic acid on diabetes associated complications using a rat model. Rats were made diabetic hypertensive by high fat diet (HFD) for 20 weeks and were treated with vanillic acid (50 mg/kg bw) for last 8 weeks. The effects of vanillic acid on glucose, plasma insulin, systolic and diastolic blood pressure, thiobarbituric acid reactive substances (TBARS), hydroperoxides as a lipid peroxidation marker, and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), vitamin C and vitamin E as an antioxidant marker, AST and ALT as a liver function marker, urea, uric acid and creatinine as a kidney function marker were investigated. Histopathology of liver and kidney was also investigated as part of the pathology of diabetes. Treatment of diabetic rats with oral administration of vanillic acid at a dose of 50 mg kg/body weight for 8 weeks resulted in a significant decrease in fasting plasma glucose, insulin and blood pressure levels in comparison with diabetic control group. The antioxidant activities were significantly increased and the levels of lipid peroxidation markers were significantly decreased in diabetic hypertensive rats treated with vanillic acid. These results suggest that vanillic acid offer a modulatory effect on control of diabetic hypertension by reduction of blood glucose, insulin and blood pressure, combating oxidative stress by activation of tissue antioxidants.