In vitro and in vivo effects of pectin‐type polysaccharides isolated from crabapples (Malus prunifolia) on inflammatory colitis models

Abstract

SummaryThe aim of this study was to investigate the anti‐inflammatory effects of polysaccharides extracted from crabapples (Malus prunifolia; MP) in vitro and in vivo. Crabapples were subjected to hot water extraction to obtain MP‐HW, which was further separated into low (MP‐L) and high molecular weight (MW) (crude polysaccharide; MP‐CP) fractions by ethanol precipitation. Based on MW distribution, general composition, component sugars, and Fourier transform infrared spectroscopy, MP‐CP was identified as a pectin‐type polysaccharide rich in galacturonic acid with an MW of 106.2 kDa. MP‐CP inhibited the production and mRNA expression of proinflammatory factors in an IL‐1β‐treated intestinal epithelial cell model. In addition, MP‐CP significantly alleviated the body weight, disease activity index score, colon length, and spleen weight in mice with dextran sulfate sodium (DSS)‐induced colitis. The MP‐CP‐treated group showed effective regulation of the expression of pro‐ and anti‐inflammatory factors and immunoglobulin A than the DSS‐treated group. Haematoxylin and eosin and Alcian blue staining revealed that MP‐CP alleviated inflammatory manifestations and mucin expression in the intestinal lumen. Collectively, pectin‐type polysaccharides isolated from crabapples may be used as a new functional food and pharmaceutical agent for the prevention and treatment of inflammatory colitis.