The Journal of Phytopharmacology 2026; 15(2):196-202 DOI:10.31254/phyto.2026.15211

Research Article

Oxidative stress and antioxidant enzyme imbalance in patients with diabetes mellitus: a cross-sectional study

Utpal Kant Singh¹ , Chanda Hemaliya¹ , Santosh Kumar Singh¹ , Arun Kumar Singh¹

Utpal Kant Singh,Chanda Hemaliya,Santosh Kumar Singh,Arun Kumar Singh

1. Department of General Medicine, Institute of Medical Sciences (IMS), Banaras Hindu University, Varanasi-221005, Uttar Pradesh, India

*Author to whom correspondence should be addressed.

Received: 5th February, 2026 / Accepted: 4th May, 2026 / Published : 8th May, 2026

Abstract

Background: Diabetes mellitus is a chronic metabolic disorder characterized by persistent hyperglycemia, leading to oxidative and nitrosative stress that contributes to microvascular and macrovascular complications. Alterations in antioxidant defense mechanisms and increased production of reactive oxygen species play a key role in diabetes-associated tissue damage. Objective: To evaluate oxidative stress markers, antioxidant enzyme activity, and the expression of insulin signaling- and glucose transporter-related genes in patients with diabetes mellitus compared with healthy controls. Materials and Methods: In this cross-sectional study, oxidative stress markers, including superoxide dismutase (SOD), NADPH oxidase activity, nitric oxide metabolites (NOx), and lipid peroxidation (LPO; malondialdehyde levels), were assessed in healthy controls (n = 15) and diabetic patients (n = 10). Gene expression analysis of insulin signaling and glucose transporter genes (IRS1, IRS2, GLUT1-4, and PPARG) was performed using quantitative PCR and normalized using the 2?ΔΔCt method. Results: Diabetic patients exhibited significantly reduced SOD activity (3.0 ± 0.3 vs 4.7 ± 0.4, p < 0.01) and NADPH oxidase activity (4.3 ± 0.5 vs 6.7 ± 0.6, p < 0.01) compared to controls. In contrast, NOx levels (48.0 ± 5.5 vs 23.0 ± 4.0, p < 0.001) and lipid peroxidation (3.9 ± 0.5 vs 1.5 ± 0.3, p < 0.001) were significantly increased. Gene expression analysis revealed significant downregulation of IRS1, IRS2, and GLUT1-4, while PPARG expression was significantly upregulated in diabetic patients. Conclusion: The findings demonstrate that diabetes mellitus is associated with oxidative stress imbalance and impaired antioxidant defence, along with altered insulin signaling gene expression. These changes may contribute to disease progression and complications, highlighting oxidative stress as a potential therapeutic target.