Inhibition of diabetes-induced oxidative-nitrative stress in rat kidneys by the alkaloid-free fraction of galega officinalis extract

Oxidative-nitrative stress induced by hyperglycaemia plays a key role in the development of complications of diabetes mellitus (DM), in particular, nephropathy. Thus, it is important to study the antioxidant activity of various compounds, including natural antioxidants of plant origin, to reduce the risk of diabetic complications. The combination of antioxidants and traditional antidiabetic drugs will provide more effective glycaemic control, and naturally occurring drugs have fewer side effects. The present study aims to investigate the corrective effect of alkaloid-free fraction (AFF) from Galega officinalis extract on the markers of oxidative and nitrative stress in the experimental diabetes mellitus (EDM) in the rat kidney. In this study, we used medicinal plant (Galega officinalis L.). This plant has long been used in folk medicine to treat mild forms of diabetes, but the content of toxic alkaloids limits the possibility of its use in therapeutic amounts. AFF enriched with components with potential hypoglycemic and antioxidant activity, and demonstrating no toxicity, was obtained from the aerial parts of Galega officinalis. An increase in the levels of stable NO metabolites – nitrite and nitrate anions and the activity of inducible NO-synthase (iNOS) was observed in the kidneys of rats, which, along with elevated levels of TBARS (thiobarbituric acid reactive substances), indicates the development of oxidative-nitrative stress under experimental diabetes mellitus (EDM) conditions. A reduction in nitrite and nitrate anion content, NOS activity, and TBARS levels was noted in diabetic animals treated with the AFF from Galega officinalis extract for 14 days. The obtained results confirm the antioxidant properties of AFF from G. officinalis extract under diabetic conditions. The main active components of G. officinalis extract responsible for its antioxidant activity are phytol, flavonoids, and phenolic acids. The combination of hypoglycemic and antioxidant effects of AFF from G. officinalis extract may not only contribute to the compensation of hyperglycemia but also reduce the risk of developing diabetes-associated complications such as neuropathy, nephropathy, and retinopathy caused by oxidative-nitrative stress.