Synergistic Therapeutic Potential of Curcumin and Metformin: a Multipathway Approach to Disease Management

Metformin, a first-line pharmacologic agent for type 2 diabetes, exerts its primary antidiabetic effects by suppressing hepatic gluconeogenesis via both AMP-activated protein kinases-dependent and -independent pathways. Beyond glycemic control, metformin exhibits pleiotropic benefits, including improved insulin sensitivity, modulation of gut microbiota, and protection against various metabolic, cardiovascular, renal, neurodegenerative, and inflammatory diseases. However, its clinical use is often limited by gastrointestinal side effects, vitamin B12 deficiency, and rare but serious complications such as lactic acidosis, highlighting the need for adjunctive strategies to enhance efficacy and reduce adverse effects. Curcumin, as a bioactive polyphenol, has garnered significant attention because of its extensive pharmacological activities and excellent safety profile. Curcumin modulates key intracellular signaling pathways, including nuclear factor-kappa B, mitogen-activated protein kinases, and phosphatidylinositol 3-kinase/protein kinase B, providing anti-inflammatory, antioxidant, anticancer, and metabolic regulatory effects. Nonetheless, its clinical application is constrained by poor bioavailability because of limited absorption, rapid metabolism, and systemic elimination. Recent evidence suggests that coadministration of metformin and curcumin yields synergistic therapeutic outcomes in diverse disease models. This combination improves glycemic control, mitigates oxidative stress and inflammation, and provides organ-protective effects, particularly in the liver, heart, and skin. Furthermore, it shows promise in cancer prevention and therapy, polycystic ovary syndrome management, and pain modulation, with enhanced outcomes when delivered via nanoparticle-based systems. This review aims to provide a comprehensive analysis of the combined therapeutic potential of metformin and curcumin across a spectrum of pathological conditions.