Structural Characterizationof a Glucan from Zingiber officinale and Its Efficacy in AlleviatingUlcerative 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.