Role of polyphenols in combating Type 2 Diabetes and insulin resistance

Compromised carbohydrate metabolism leading to hyperglycemia is the primary metabolic disorder of non-insulin-dependent diabetes mellitus. Reformed digestion and altered absorption of carbohydrates, exhaustion of glycogen stock, enhanced gluconeogenesis and overproduced hepatic glucose, dysfunction of beta-cell, resistance to insulin in peripheral tissue, and impaired insulin signaling pathways are essential reasons for hyperglycemia. Although oral anti-diabetic drugs like alpha-glucosidase inhibitors, sulfonylureas and insulin therapies are commonly used to manage Type 2 Diabetes (T2D) and hyperglycemia, natural compounds in diet also play a significant role in combating the effect of diabetes. Due to their vast bioavailability and anti-hyperglycemic effect with least or no side effects, polyphenolic compounds have gained wide popularity. Polyphenols such as flavonoids and tannins play a significant role in carbohydrate metabolism by inhibiting key enzymes responsible for the digestion of carbohydrates to glucose, viz. alpha-glucosidase and alpha-amylase. Several polyphenols such as resveratrol, epigallocatechin-3-gallate (EGCG) and quercetin enhanced glucose uptake in the muscles and adipocytes by translocating GLUT4 to plasma membrane mainly by the activation of the AMP-activated protein kinase (AMPK) pathway. This review provides an insight into the protective role of polyphenols in T2D, highlighting the aspects of insulin resistance.

Automated summary

Compromised carbohydrate metabolism leading to hyperglycemia is the primary metabolic disorder of non-insulin-dependent diabetes mellitus. Polyphenolic compounds play an important role in regulating insulin resistance and carbohydrate metabolism through inhibiting key enzymes and activating specific pathways to control blood glucose levels.