Amelioration of oxidative stress by dietary fenugreek (Trigonella foenum-graecum L.) seeds is potentiated by onion (Allium cepa L.) in streptozotocin-induced diabetic rats.

Oxidative stress has a crucial role in the progression of diabetes and its complications. Soluble fibre-rich fenugreek seeds (Trigonella foenum-graecum L.) are understood to have a beneficial effect in the management of diabetes. Previously, we have shown that the amelioration of diabetic hyperglycemia and related metabolic abnormalities was potentiated by onion (Allium cepa L.) in experimental rats. The present study evaluated the additive beneficial effect of dietary fenugreek seeds (10%) and onion (3%) on oxidative stress in diabetic rats. These dietary interventions lowered oxidative stress, the combination producing a higher beneficial effect (p < 0.05), although not additive. Dietary fenugreek, onion, or fenugreek+onion countered hypercholesterolemia (p < 0.05), especially from low-density lipoprotein-associated fraction by 43%, 35%, and 54%, respectively. Elevated concentrations of cholesterol and triglycerides in the liver and heart under diabetic conditions were significantly counteracted by these dietary interventions, with the additive combination resulting in greater effect. These findings were also corroborated by restoration of histopathological abnormalities of heart and liver tissues along with lowered heart and liver weights. It is inferred that an alleviation of oxidative stress contributes further to the antidiabetic influence and this nutraceutical potential of fenugreek seeds and onion was higher when consumed together.