Phytochemical–SGLT2 Inhibitor Combinations in Type 2 Diabetes: Mechanistic Complementarity, Preclinical Evidence and Translational Perspectives

Abstract

Type 2 diabetes mellitus (T2DM) is a multifactorial metabolic disorder in which insulin resistance, progressive impairment of pancreatic β-cell function, abnormal hepatic glucose production and disturbances in lipid metabolism contribute to persistent hyperglycemia. Sodium-glucose cotransporter 2 (SGLT2) inhibitors have become an important component of diabetes pharmacotherapy because they lower blood glucose by reducing renal glucose reabsorption and promoting urinary glucose excretion. Their pharmacological effects, however, extend beyond glucose lowering and include mechanisms that may contribute to renal and cardiovascular protection. Phytochemicals have also attracted considerable interest in diabetes research because many of these naturally occurring compounds can influence glucose metabolism, insulin signaling, oxidative stress, inflammation and lipid homeostasis. These actions provide a potential basis for combining selected phytochemicals with established SGLT2 inhibitors. The rationale for such combinations is not necessarily based on both agents acting on the same molecular target; rather, complementary effects on different components of diabetic pathophysiology may provide a basis for investigation. At present, however, direct evidence for phytochemical–SGLT2 inhibitor combinations remains limited compared with the extensive literature available for individual agents. This review examines the pharmacological basis and available experimental evidence for combining phytochemicals with SGLT2 inhibitors, with particular attention to chlorogenic acid, resveratrol, quercetin, curcumin and berberine. Evidence from direct combination studies is distinguished from findings derived from monotherapy experiments, cellular models and mechanistic or computational investigations. Among the available combination studies, resveratrol with dapagliflozin provides an example of mechanistically supported combination research, with reported effects involving PI3K/Akt and FoxO1-related pathways. Emerging evidence involving quercetin-rich preparations and dapagliflozin has also suggested an additive response, although formal pharmacological synergy has not been established. Several factors currently limit translation of this research into clinical practice. These include poor or variable phytochemical bioavailability, differences in botanical composition, dose standardization, possible pharmacokinetic interactions and the limited number of adequately designed human combination studies. Future research should therefore focus on standardized phytochemicals, well-characterized SGLT2 inhibitor combinations, pharmacokinetic/pharmacodynamic assessment and experimental designs capable of distinguishing additive effects from true synergy. Phytochemical–SGLT2 inhibitor combinations remain an emerging area of drug-discovery research, and their therapeutic potential requires further systematic investigation before clinical conclusions can be drawn.