Flavonoid-Rich mulberry leaf extract modulate lipid metabolism, antioxidant capacity, and gut microbiota in high-fat diet-induced obesity: potential roles of FGF21 and SOCS2

Mulberry leaves are a rich source of active ingredients exhibiting notable antioxidant activity and have been demonstrated to possess hypolipidemic and hypoglycemic effects. Non-alcoholic fatty liver disease (NAFLD), the most prevalent chronic liver disease, is increasingly prevalent worldwide, with a strong correlation between NAFLD occurrence and obesity. We aimed to investigate the association between the active ingredient targets in mulberry leaves and stems and the disease targets of NAFLD/NASH through network pharmacology, and designed animal experiments to verify our findings. In addition to the normal and model groups, three intervention groups were established for the experiment: the mulberry leaf aqueous extract (MLQE), Orlistat, and swimming exercise groups. The intervention effect of MLQE on NAFLD was observed by comparing it with widely recognized weight loss drugs and exercise interventions. The results demonstrated that all three interventions effectively reduced body weight and body fat, exhibited robust antioxidant capacity, and significantly improved the dysbiosis of gut microbiota induced by a high-fat diet. Histological analysis also supported the conclusions of lipid-lowering, anti-inflammatory, and amelioration of liver injury. Through RNA-seq analysis, we identified the key genes FGF21 and SOCS2 that may be associated with the effective intervention of mulberry leaves in NAFLD, and validated the genes and proteins related to NAFLD and lipid metabolism by qPCR and WB analysis. Our study found that MLQE has an anti-NAFLD effect not inferior to orlistat and swimming exercise, indicating that it is a promising candidate for the treatment of NAFLD. Meanwhile, FGF21 and SOCS2 may be key targets for the treatment of NAFLD, and more studies are needed to verify this.