UPLC-QE-Orbitrap-MS-Based Metabolomics and Gut Microbiome Analysis to Reveal Codonopsis pilosula (Franch.) Nannf. Extract Improves Cyclophosphamide-Induced Immunosuppression in Mice

Immune system dysfunction leads to recurrent or severe infections, increased susceptibility to concurrent illnesses, and heightened risk of tumors. Current immunomodulators often carry side effects, whereas phytotherapy offers relative stability, making this therapeutic approach worthy of exploration. Codonopsis pilosula (Franch.) Nannf. nourishes blood, generates fluids, and tonifies qi to address deficiency. Codonopsis pilosula water extract (LDSOL) possesses immune-enhancing properties, but its potential biomarkers and mechanisms of action remain unclear. This study investigated the pharmacological basis of LDSOL using a cyclophosphamide-induced immunosuppression mouse model. Results showed that oral administration of LDSOL alleviated hepatosplenomegaly and thymic atrophy, regulated white and red blood cell counts, significantly elevated IL-2, IL-6, TNF-α, IFN-γ, and IgG concentrations, modulated Th17/Treg and Th1/Th2 cell ratios, and enhanced the body's immune response capacity. Metabolomics combined with 16S rRNA gut microbiota analysis suggested that LDSOL may enhance immune function by regulating endogenous metabolites (L-phenylalanine, serotonin, methionine sulfoxide, propionylcarnitine) and immune-related gut microbiota (Lactobacillus, Ruminococcus, Bacteroides). Multi-omics correlation analysis indicates that LDSOL exerts immunomodulatory effects by regulating Serotonin, 5-Hydroxytryptophan, and L-Glutamine through modulating microbial communities such as Ligilactobacillus, Longibaculum, and Pseudomonadota. In summary, LDSOL effectively mitigates immune organ damage, significantly improves blood cell counts, cytokine levels, and immune cell ratios. It enhances immunity by regulating metabolism and the gut microbial environment while alleviating immunosuppression.