Flavonoids of Mao Jian Green Tea Ameliorate Glycemic Metabolism in Type-2-Diabetic Rats via AMPK Signaling Pathways and Gut Microbiota Regulation

Mao Jian Green Tea flavonoids (MJGT_F) contain luteolin, luteolin-7-O-glucoside, eriodictyol, and eriodictyol-7-O-glucoside, among which the first three components have hypoglycemic effects; however, the overall hypoglycemic potential of MJGT_F remains unclear. This study demonstrated that MJGT_F inhibited α-glucosidase in vitro and improved metabolic parameters in a dose-dependent manner in T2DM (type 2 diabetes mellitus) rats (reducing blood glucose, triglyceride, total cholesterol, low-density lipoprotein, insulin, and the homeostatic model assessment of insulin resistance; increasing high-density lipoprotein, insulin sensitivity index, and glucagon-like peptide-1). High-dose MJGT_F (MJGT_F_H) showed optimal efficacy. Mechanistically, MJGT_F_H activated the AMPK pathway, evidenced by a significant increase in the p-AMPK/AMPK ratio and downregulation of hepatic gluconeogenic enzymes G6Pase and PEPCK. These coordinated effects collectively suggest enhanced hepatic glucose utilization and suppression of glucose overproduction. MJGT_F_H also modulated gut microbiota by enriching beneficial taxa (e.g., Akkermansia muciniphila, 11.17-fold vs. metformin) and reducing pathogens like Enterobacteriaceae. These findings highlight MJGT_F’s dual regulatory roles in glucose metabolism and microbiota, supporting its potential for diabetes management.