Abstract
BACKGROUND: Accumulating evidence suggests that metabolic disorders, including type 2 diabetes mellitus (T2DM), can be treated with traditional Chinese medicine formulas, such as the Gegen Qinlian decoction (GQD). This study elucidates the mechanisms by which gut microbes mediate the anti-diabetic effects of GQD. METHODS: We conducted a double-blind randomized clinical trial involving 120 untreated participants with T2DM. During the 12-week intervention, anthropometric measurements and diabetic traits were recorded every 4 weeks. Fecal microbiota and serum metabolites were measured before and after the intervention using 16S rDNA sequencing, liquid chromatography-mass spectrometry, and Bio-Plex panels. RESULTS: Anti-diabetic effects were observed in the GQD group in the human trial. Specifically, glycated hemoglobin, fasting plasma glucose, and two-hour postprandial blood glucose levels were significantly lower in the GQD group than in the placebo group. Additionally, Faecalibacterium was significantly enriched in the GQD group, and the short-chain fatty acid levels were higher and the serum inflammation-associated marker levels were lower in the GQD group compared to the placebo group. Moreover, Faecalibacterium abundance negatively correlated with the levels of serum hemoglobin, fasting plasma glucose, and pro-inflammatory cytokines. Finally, the diabetes-alleviating effect of Faecalibacterium was confirmed by oral administration of Faecalibacterium prausnitzii (DSMZ 17677) in T2DM mouse model. CONCLUSIONS: GQD improved type 2 diabetes primarily by modulating the abundance of Faecalibacterium in the gut microbiota, alleviating metabolic disorders and the inflammatory state. TRIAL REGISTRATION: Registry No. ChiCTR-IOR-15006626.