Bergamot polysaccharides relieve DSS-induced ulcerative colitis via regulating the gut microbiota and metabolites

This study aimed to explore the efficacy of polysaccharides from bergamot (BP) in alleviating DSS-induced colitis. Results showed that BP was primarily composed of two components, BP-1 and BP-2, with similar monosaccharide compositions to BP (mainly glucose and xylose) and molecular weights (Mw) of 4.50 × 10⁵ and 2.35 × 10⁵ Da. This study found BP relieved disease symptoms such as weight loss and colon shortening in mice with colitis. Gut microbiota and metabolomics analysis revealed that the BP could also promote the proliferation of beneficial bacteria such as Bifidobacteria, Butyrivibrio, and Blautia, resulting in increased levels of SCFAs and L-phenylalanine, which were associated with phenylalanine, tyrosine, and tryptophan metabolism pathways. Further analysis validated the inflammatory activity of L-phenylalanine. Hence, BP may relieve colitis symptoms by regulating the gut microbiota and metabolism, which reduced inflammation and enhanced the expression of tight junctional proteins (TJ proteins) and mucin in the intestine.