Structural Characterization of a Glucan from Zingiber officinale and Its Efficacy in Alleviating Ulcerative Colitis by Ameliorating Gut Microbiota Imbalance

Natural polysaccharides derived from Zingiber officinale (ZO) can alleviate ulcerative colitis (UC). In this study, a homogeneous glucan, ZOP-1a (250.39 kDa), was isolated from ZO and structurally characterized. ZOP-1a possessed an α-1,4-d-Glcp backbone, with branches substituted at H-6 by α-d-Glcp-(1 → 6)-α-d-Glcp-(1→ and at H-3 by α-d-Glcp-(1 → 3)-β-d-Glcp-(1→ and α-d-Glcpp-(1→ residues. In DSS-induced colitis mice, ZOP-1a markedly ameliorated colon injury, as reflected by improved body weight, colon length, and histopathological damage, inhibited NF-κB/MAPK signaling and reshaped gut microbiota dysbiosis, thereby restoring intestinal homeostasis. Moreover, ZOP-1a increased the abundance of short-chain fatty acid (SCFA)-producing bacteria, and in vitro Lactobacillus fermentation supported its potential contribution to SCFA generation. Fecal microbiota transplantation from ZOP-1a-treated colitis mice effectively alleviated UC symptoms in recipient mice. Overall, ZOP-1a may serve as a promising prebiotic candidate for maintaining intestinal homeostasis and preventing UC.