Focus on gut microbiota regulation: exploring the potential of fermented traditional Chinese medicines in the prevention and treatment of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM), a globally prevalent metabolic disorder, has dysbiosis of the gut microbiota as a significant pathogenic factor. Traditional Chinese medicine (TCM) fermentation, originating from traditional processing techniques, is a technology that combines modern microbiological methods with solid-state fermentation, submerged fermentation, and bidirectional fermentation of medicinal fungi. Under specific conditions, it facilitates the biotransformation of herbal raw materials, demonstrating distinct advantages in regulating gut microbiota. This study aims to outline the concept of fermented TCM, elucidate the relationship between gut microbiota and T2DM, and explore the mechanisms by which fermented TCM modulates gut microbiota to improve T2DM. Literature searches in databases such as PubMed, Google Scholar, and Web of Science reveal that fermented TCM improves T2DM by targeting gut microbiota regulation as a core mechanism. The mechanisms may involve: modulating gut microbiota composition (fermentation products increase beneficial bacteria abundance, decrease harmful bacteria proportion, and restore microbial balance); influencing gut microbiota metabolites (promoting short-chain fatty acid (SCFA) production by microbiota, which participates in glucose and energy metabolism); protecting intestinal barrier function (SCFAs enhance intestinal epithelial cell function, upregulate tight junction protein expression, preserve barrier integrity, and reduce endotoxin leakage into the bloodstream); and modulating intestinal immune function (inhibiting inflammatory responses, enhancing antioxidant activity, and regulating intestinal immune homeostasis). This study reviews the application research of fermented TCM in improving T2DM by regulating the gut microbiota, aiming to validate and reveal its potential in the prevention and treatment of T2DM through gut microbiota modulation.