Diabetes-Induced Damages in Rat Kidney and Brain and Protective Effects of Natural Antioxidants

Context: In case of diabetes, persistent and chronic hyperglycaemia may generate free radicals and reactive oxygen species (ROS), which trigger an oxidative stress. Garlic (Allium sativum) is a rich source of bioactive compounds and is used in folk medicine for the treatment of various diseases, including diabetes. Besides, α-tocopherol and magnesium have been shown to possess antioxidative properties. Objective: Protective effects of either a garlic aqueous extract or an association of α-tocopherol and magnesium association upon oxidative stress and dysfunctions in kidney and brain of alloxan-diabetic rats were investigated. Results: Both garlic extract and the combination of α-tocopherol and magnesium were found to normalize many parameters which were shifted to pathological values as a consequence of the alloxan-induced diabetes: plasma creatinine and urea levels were decreased, protein leakage in urine was reduced and cortisol level was brought back to control value. In addition, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities, which were lowered in kidney and brain of diabetic animals, were restored by both treatments and, consequently, level of lipids peroxidation was reduced in these organs, as compared to diabetic animals. Conclusion: Both garlic extract and α-tocopherol + magnesium association display beneficial effects upon nephropathy and oxidative stress in alloxan-diabetic rats. The protective effect of garlic is mainly attributed to antioxidant properties and the presence of phenolic acids and flavonoids.