Impact of purple sweet potato (Ipomoea batatas L.) polysaccharides on the fecal metabolome in a murine colitis model

Purple sweet potato polysaccharides (PSPP) play an important role in regulating the gut microbiota, modulating intestinal immunity and ameliorating colonic inflammation. In this study, the impact of two PSPPs (PSWP-I and PSAP-I) on the metabolomic profiling of feces from dextran sulfate sodium (DSS)-induced colitis mice was evaluated by ultra-high performance liquid chromatography coupled with triple time-of-flight tandem mass spectrometry (UPLC-Triple-TOF-MS/MS). Results indicated that there were twenty-five metabolites with significant changes and four remarkable metabolic pathways, i.e., cutin, suberine and wax biosynthesis, biosynthesis of unsaturated fatty acids, fatty acid biosynthesis, and steroid hormone biosynthesis. Two key biomarkers of oleic acid and 17-hydroxyprogesterone were screened that responded to PSPPs in colitis mice. The identified metabolites were correlated with the amelioration of intestinal immune function and the modulation of the gut microbiota. Nine pro-inflammatory and eight anti-inflammatory compounds responded to PSPPs, which were related to Bacteroides, norank_f__Clostridiales_vadinBB60_group, unclassified_o__Bacteroidales, Rikenella and Lachnospiraceae_UCG-001. Moreover, PSWP-I and PSAP-I had different regulating effects on intestinal metabolites. Our results revealed a possible metabolomic mechanism of PSPPs to regulate intestinal inflammation function.