Antidiabetic and antistress effects of Withania somnifera root extract in STZ-induced diabetes in Wistar rats

Abstract

Diabetes mellitus is a major metabolic disorder of both humans and animals, characterized by persistent hyperglycaemia and associated complications that significantly impact health and productivity. Conventional therapies, though effective, are often limited by cost and adverse effects, prompting interest in herbal alternatives. The present study was undertaken to evaluate the antidiabetic and antistress effects of aqueous extract of Withania somnifera root in streptozotocin (STZ)-induced diabetic Wistar albino rats and to compare its efficacy with metformin, including assessment of their combined potential. Male Wistar rats were divided into six groups (n=6 each): normal control, diabetic control, W. somnifera control, metformin-treated (100 mg/kg bw), W. somnifera-treated (200 mg/kg bw), and combination therapy (W. somnifera 100 mg/kg bw + metformin 50 mg/kg bw). Diabetes was induced with STZ (55 mg/kg bw, i.p.), and treatments were administered orally for 45 days. Diabetic rats exhibited classical symptoms including hyperglycaemia, weight loss, and oxidative stress. Treatment groups showed significant improvement in serum glucose, lipid profile, liver enzymes, cortisol levels, and antioxidant enzyme activities (SOD, CAT, GPx), with concomitant reduction in MDA levels. Histopathological examination revealed marked organ damage in diabetic controls, which was considerably ameliorated in treated groups. Metformin exerted a stronger antihyperglycemic effect compared to W. somnifera, while the latter demonstrated pronounced antistress activity. Combination therapy produced enhanced recovery, though without statistically significant synergism. The findings suggest that W. somnifera possesses notable antidiabetic and potent antistress properties, and its use in conjunction with metformin may offer therapeutic benefits in the management of STZ-induced diabetes and associated complications.