Mechanisms of Fuling Zexie decoction against metabolic dysfunction-associated steatotic liver disease: Integrative metabolomics, gut microbiota and serum pharmacochemistry

BACKGROUNDMetabolic dysfunction-associated steatotic liver disease (MASLD) currently lacks specific therapeutic options.Fuling Zexie decoction (FZD) is a Chinese herbal formula that shows potential for treating MASLD, but its mechanism and active ingredients remain unclear. AIMTo explore the mechanism and active ingredients of FZD against MASLD. METHODSFree fatty acid-stimulated steatotic HepG2 cells and high-fat diet-fed MASLD rats were used to assess the functionality of FZD.To investigate the mechanisms by which FZD affects endogenous metabolites and intestinal microbiota in rats, a combination of metabolomics and 16S rRNA sequencing was utilized.Serum pharmacochemistrymetabolomics integration identified FZD's active ingredients and core targets, while molecular docking and cellular experimentation were utilized for the validation of the association of these ingredients and targets. RESULTSFZD ameliorated hepatic steatosis and hepatocellular injury in rats with MASLD, ameliorated serum and hepatic lipid levels, augmented antioxidant capacity, and mitigated inflammatory responses.Mechanistically, FZD restored 226 endogenous metabolites and regulated 17 metabolic pathways.This included reducing the Firmicutes/Bacteroidota ratio and diminishing the levels of potentially harmful microbes (Unclassified_f_Lachnospiraceae, Candidatus Saccharimonas, and Turicibacter).A total of 39 FZD-originated constituents were detected in the serum.Among these, 24 were recognized as key pharmacodynamic constituents that modulated 17 targets, 10 metabolic pathways, and 18 endogenous metabolites.The key pharmacodynamic 4 / 66 compound group downregulated the expression of NOS2, MAOA, and MIF, thereby alleviating hepatic steatosis. CONCLUSIONThe results demonstrate that FZD alleviates MASLD by regulating 10 metabolic pathways, decreasing the abundance of Unclassified_f_Lachnospiraceae, Candidatus Saccharimonas, and Turicibacter, and normalizing 18 endogenous metabolite levels, which may be primarily attributed to the 24 FZD-derived active ingredients.