An arabinogalactan from Lycium barbarum attenuates DSS-induced chronic colitis in C57BL/6J mice associated with the modulation of intestinal barrier function and gut microbiota

Ulcerative colitis (UC) is an incurable chronic inflammation of the enteric tract. The aim of this study was to investigate the protective effects of arabinogalactan from Lycium barbarum on DSS-induced chronic colitis. A homogeneous arabinogalactan was isolated and purified from L. barbarum, named LBP-3, which mainly consisted of arabinose and galactose with a molar ratio of 1.00 : 0.82. LBP-3 treatment remarkably alleviated body weight loss, histopathological damage and the overproduction of pro-inflammatory cytokines and enzymes in UC mice. Additionally, the intestinal barrier integrity was partially recovered by the up-regulated expression of MUC2 and tight junction proteins. Moreover, the gut microbiota shift was reversed by LBP-3 administration by enriching potential probiotic bacteria (e.g., Ruminococcaceae) and inhibiting the proliferation of harmful bacteria (e.g., Enterobacteriaceae). Furthermore, SCFAs, as major metabolites of LBP-3 fermentation by gut microbiota, were also promoted so as to maintain relatively favorable intestinal homeostasis. Overall, our findings suggested LBP-3 from L. barbarum could be a potential therapeutic candidate against UC via improving intestinal barrier function and partially restoring gut microbiota and its metabolites.