Onion peel extracts ameliorate oxidative stress in streptozotocin-induced diabetic rats

Abstract

Background: Onion peel extracts contain quercetin derivatives, flavonoids that have been shown to significantly improve diabetic status and to exhibit antioxidant properties in animal models. Vitamin E is an important antioxidant that is present within the cell membrane and acts as a lipid-soluble scavenger. This study aimed to compare the efficacy of an onion peel extract and vitamin E to alleviate the altered redox balance of diabetic rats. Methods: Streptozotocin-induced diabetic male Wistar rats (n = 34) were randomly divided into three treatment groups. For 45 days, the first group was fed a normal diet (diabetic control group), the second group was fed a normal diet plus 20 mg/kg body weight vitamin E and the third group was fed a normal diet plus 1% OPE . Results: The formation of malondialdehyde and protein carbonyls was significantly suppressed and the activity of superoxide dismutase was increased in different areas of the brain upon onion peel extract administration (P < 0.001) compared to the diabetic control group. Furthermore, vitamin E did not significantly decrease the level of oxidative stress or the blood glucose concentration in these rats. Conclusion: OPE is better able to ameliorate oxidative stress and hyperglycaemia than vitamin E in a diabetic rat model.