Serum metabonomic study to explore the amelioration mechanisms of co-fermented collagen peptide-jackfruit juice on the immunosuppressed mice

The main purpose of this study was to investigate the improvement effect and serum metabolomic analysis of co-fermented collagen peptide-jackfruit juice (FPJ) against immunosuppression in cyclophosphamide-induced mice. Serum samples were analyzed using ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS/MS) targeted metabolomics technology, including the normal group, model group, and FPJ group, and determine if such treatments were able to revert immunosuppression-related metabolic changes to normal status. The results showed that 32 differential metabolites were upregulated and 42 metabolites were downregulated in the model group compared with the normal group. After FPJ intervention, there was a trend of normal callback. Adenosine, inosine, guanosine, 2-deoxyadenosine, hypoxanthine, xanthine,  d-xylulose-5-phosphate, ribulose-5-phosphate, phenylpyruvic acid, hippuric acid, 3-(3-hydroxyphenyl)-propionic acid, 3-ureidopropionate, uridine, dCDP and malonic acid may be used as predictive markers of immunosuppression. Notably, these biomarkers were involved in purine metabolism, pentose phosphate pathway, phenylalanine metabolism, and pyrimidine metabolism. In this study, FPJ inhibited oxidative stress and improved the gut microbes by regulating the disorders of metabolic pathways. The metabolomics approach developed herein provides novel insight into the metabolic disturbances associated with immunosuppression, which will contribute to understanding the mechanism of FPJ on immunosuppression further and providing a basis for further research.