Integrated network pharmacology, gut microbiome, and metabolomics analyses reveal the protective mechanism of Guizhi Gegen decoction against influenza.

Guizhi Gegen Decoction (GGD), a classical formula first recorded in the Treatise on Febrile Diseases, has been commonly used in clinical practice for the treatment of influenza, but its underlying mechanism remains unclear. This study aimed to elucidate the protective mechanisms of GGD against influenza using an integrated approach combining network pharmacology, microbiomics, and serum metabolomics. The results showed that GGD significantly alleviated influenza-induced injury, as indicated by improved body weight, reduced lung index and viral load, decreased inflammatory cytokine expression (IL-2, IL-6, IFN-γ, TNF-α, ROR-γt, and GM-CSF) in lung and intestinal tissues, and ameliorated histopathological damage. Mechanistically, GGD suppressed the STAT3/HIF-1α signaling axis and downregulated downstream pro-inflammatory mediators. In addition, GGD restored gut microbial homeostasis in influenza mice, characterized by increased relative abundance of p_Bacteroidetes and reduced abundance of p_Actinobacteria, c_Flavobacteriia, c_Alphaproteobacteria, and c_Betaproteobacteria. Serum metabolomics further demonstrated that GGD significantly corrected influenza-associated metabolic disturbances, particularly by regulating metabolites such as indole-3-acrylic acid, gentisic acid, epinephrine, and 5-aminovaleric acid. Correlation analyses revealed close associations among differential microbial taxa, serum metabolites, and host pathological indicators. In conclusion, GGD ameliorates influenza-induced pulmonary and intestinal injury by reshaping gut microbial composition, restoring metabolic homeostasis, and inhibiting the STAT3/HIF-1α signaling pathway.