Adzuki Bean Water Extract Attenuates Obesity by Modulating M2/M1 Macrophage Polarization and Gut Microbiota Composition

Scope Obesity is a chronic condition resulting in excessive fat accumulation in adipose tissues. Adipose tissue is now considered as an immune organ, at the crossroads between metabolism and immunity. Thus, this study investigates the effects of adzuki beans on obesity and gut microbiota in high fat diet-induced mice. Methods and results In this study, adzuki bean hot water extract (AWE) is determined to have the most significant anti-adipogenic effect; it is able to inhibit lipid accumulation in 3T3-L1 adipocytes and reduces body weight and adipose tissue weight in a dose-dependent manner. AWE treatment also decreases M1-polarized adipose tissue macrophages (ATMs) while inducing M2-polarized ATMs. The number and size of fat vacuoles in liver lesions are significantly reduced, indicating that AWE could ameliorate steatosis in high fat diet-induced mice. The results also demonstrate that AWE-treated groups inhibit adipogenesis via activating the Wnt/beta-catenin pathway and reduce peroxisome proliferator-activated receptor gamma and CCAAT/enhancer binding proteins alpha expression. Moreover, the studies confirm that AWE decreases obesity through modulating gut microbiota. Conclusion The results demonstrate that AWE supplementation ameliorates high fat diet-induced obesity and gut microbiota composition and suggests that AWE may have the potential to be developed into a functional food to improve metabolic disorders.