Preparation and structure characterization of a natural acetylated fructooligosaccharide from Polygonatum sibiricum and its alleviative effect on colitis by inhibiting NLRP3 pathway

This study aimed to isolate oligosaccharides from P. sibiricum , analyze its structure, and elucidate the pharmacological mechanism for colitis improvement. First, a homogeneous oligosaccharide PSO-A was isolated and its structure was characterized. Then, the colitis model was induced with 3 % dextran sulfate sodium (DSS) and intervened with PSO-A. The results show that PSO-A was an agavin-type acetylated fructooligosaccharide with a molecular weight of 2.12 kDa. PSO-A consisted of (2 → 6)-β-D-Fru f residue backbone with an internal α-D-Glc p residue and (2 → 1)-β-D-Fru f residue side chains. Further, PSO-A increased mucin content, protected intestinal barrier integrity of colitis mice, and significantly inhibited the levels of inflammatory factors. Moreover, the protein expressions of NLRP3, ASC, and Caspase-1 in colitis mice was statistically inhibited by PSO-A. In summary, PSO-A could alleviate colitis by inhibiting NLRP3 inflammasome pathway, which provides a basis for the development and application of P. sibiricum oligosaccharides as drug or functional food to relieve colitis.