Investigation of the anti-hyperglycemic and antioxidant effects of wheat bread supplemented with onion peel extract and onion powder in diabetic rats

Abstract

Aim Onion is one of the commonly cultivated and consumed vegetables rich in nutrients and phytochemicals. Various nutraceuticals are found in the outer fleshy layers and dry peel of onion which usually is treated as a common biowaste. Diabetes mellitus is a leading non communicable disease causing hyperglycemia and increased production of free radicals that potentially disrupts antioxidant enzymatic activity. Considering global consumption of wheat, the present study was designed to evaluate the anti-hyperglycemic and antioxidant effects of wheat bread supplemented with onion peel extract (OPE) or onion powder (OP) on diabetic rats. Methods In this study, ethanolic extract of onion peel and onion bulb were prepared separately. Male Sprague Dawley rats were divided into 6 groups (n = 7). Different regimens of supplemented wheat bread (OPE (1% and 3%) and OP (5% and 7%)) were given to diabetic rats for eight weeks, plain bread was used as the control. Blood glucose level, body weight and activities of SOD, CAT, GPx, GR, GSH and MDA in the liver and kidney tissues were evaluated. Statistical analysis was performed using SPSS Version (25) and Dunnett’s multiple comparison test. Results Bread supplemented with 1% and 3% onion peel extract and 7% onion powder significantly reduced blood glucose levels and MDA in the treated rats compared with the control group diabetic rats. Body weight of diabetic rats was reduced for control group, while onion supplemented diet improved the body weight of treated rats. Onion supplementation also brought significant improvement in antioxidant enzyme activities among the treated diabetic rats. Conclusion These findings suggested that onion supplementation is effective in lowering blood glucose and could potentially aid in protecting organs from oxidative stress.

Innovative Application of Chicken Eggshell Calcium to Improve the Functional Value of Gingerbread

“…Bread products are also preferred by the elderly, who are at a greater risk of osteoporosis, from different regions in the world [ 18 ]. A study reported that wheat bread supplemented with the antioxidant from onion brought a significant improvement in antioxidant enzyme activities of diabetic rats [ 35 ]. Pastoriza et al [ 36 ] reported the positive effect on the antioxidant defense in the liver of rats after a long-term Maillard reaction products-containing bread crust diet, manifested in increased antioxidant enzyme activities and glutathione.…”

Hepatoprotective Effect of Actinidia deliciosa against Streptozotocin-Induced Oxidative Stress, Apoptosis, and Inflammations in Rats

“…These results support the hypothesis that hyperglycemia in diabetes is linked with oxidative stress, the formation of ROS, or the shortage of antioxidant defensive systems [ 23 ]. Furthermore, the considerable reduction in enzymatic and nonenzymatic antioxidants in diabetic rats could be related to an increase in ROS production, as well as the presence of H 2 O 2 and other hydrogen radicals [ 4 , 21 , 24 , 25 ]. Because glutathione is an important nonenzymatic antioxidant involved in maintaining cellular integrity, its depletion signals the advancement of cellular damage caused by free radicals.…”

“…Kiwifruit is also a good source of antioxidants and natural pancreatic lipase and α -glucosidase inhibitors [ 47 ]. Similarly, diabetic rats given onion as part of their diet had considerably higher body weights and antioxidant enzyme activity [ 25 ]. In diabetic rats, hesperetin, a citrus flavonoid, also attenuates high blood glucose and lipid levels through boosting antioxidant proficiency.…”

Antioxidant potential and α-glucosidase inhibitory activity of onion (Allium cepa L.) peel and bulb extracts

“…Several researches conducted on plants and herbs which contain phenolics in abundant quantities have reported a link between antioxidant activity of extract and inhibition of α-glucosidase activity (Kwon et al, 2006) and particularly Allium cepa bulb have been evaluated for it's several physiological effects including anti-diabetic properties (Wu and Xu, 2011). But for onion outer skin and peels very few studies have investigated their anti-diabetic potential even though they present great concentrations of phytochemicals (Masood et al, 2021). It was stated that methyl alcohol extracts of Allium cepa.…”