Inhibition of Diabetes-Related Enzymes by Plant Secondary Metabolites: A Promising Therapeutic Strategy

Diabetes mellitus is a chronic and increasingly prevalent metabolic disorder characterized by persistent hyperglycemia, resulting from defects in insulin secretion, insulin action, or both. Despite the availability of pharmacological agents that effectively manage blood glucose levels, many are associated with adverse effects, limited efficacy over time, and high costs. Consequently, there is growing interest in alternative therapies, especially those derived from traditional medicinal plants, that have long been employed in various cultures for managing diabetes. Recent advances in phytochemistry have identified bioactive plant secondary metabolites with promising antidiabetic properties. This review aims to provide a comprehensive overview of plant-derived compounds that exhibit inhibitory activity against key diabetes-related enzymes, including α-glucosidase, α-amylase, protein tyrosine phosphatase 1B (PTP1B) and dipeptidyl peptidase-4 (DPP-4). These enzymes play critical roles in glucose metabolism and insulin signaling pathways. The review highlights the structural diversity of these natural inhibitors, their mechanisms of action, and their effectiveness in preclinical models. Understanding the molecular interactions and pharmacological profiles of these metabolites may facilitate the development of safer and more effective antidiabetic agents.