Natural Products in Diabetes Mellitus: A Narrative Review of Mechanistic Insights into Metabolic Regulation and Therapeutic Potential.

Diabetes mellitus is a complex metabolic disease characterized by persistent hyperglycemia resulting from impaired insulin secretion, insulin action, or both. In addition to disturbances in glucose metabolism, the disease is accompanied by abnormalities in mitochondrial dysfunction, oxidative stress, lipid and protein metabolism, and chronic inflammation that contribute to progressive tissue injury and the development of vascular complications. Although current pharmacological therapies effectively improve glycemic control, many patients continue to experience disease progression and diabetes-associated complications, highlighting the need for complementary therapeutic strategies that target multiple pathogenic mechanisms. Growing evidence suggests that naturally occurring bioactive compounds may provide such multitarget benefits. Plant-derived polyphenols, medicinal herbs, culinary spices, and functional foods have demonstrated antioxidant, anti-inflammatory, hypoglycemic, hypolipidemic, and insulin-sensitizing properties in experimental and clinical studies. Compounds including curcumin, honey, garlic, fenugreek, cumin, shilajit, and guduchi have been reported to influence several molecular pathways involved in diabetes pathogenesis, including NF-κB-mediated inflammatory signaling, oxidative and endoplasmic reticulum stress, PPARγ activation, advanced glycation end-product formation, and pancreatic β-cell preservation. This review critically examines current evidence regarding the role of natural products in diabetes management, integrating findings from cell-based studies, animal models, and human clinical investigations. Particular emphasis is placed on the interplay between oxidative stress, inflammation, mitochondrial dysfunction, and metabolic regulation, as these interconnected processes represent key drivers of disease progression. In addition to summarizing established mechanisms, the review discusses current limitations, translational challenges, and future research priorities. A deeper understanding of how natural products modulate these pathways may facilitate the development of evidence-based adjunctive strategies to improve long-term metabolic health and reduce the burden of diabetic complications. This narrative review critically synthesizes published peer-reviewed mechanistic, preclinical, and clinical evidence regarding selected natural products and functional foods relevant to diabetes mellitus.