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)-beta-D-Fruf residue backbone with an internal alpha-D-Glcp residue and (2 -> 1)-beta-D-Fruf 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.