A comprehensive understanding of the relationships between the structure and function is critical for the targeted preparation of functional pectins. In this study, we compared the alleviating effects of five orange pectins (200 mg/kg) extracted using acid (P2), alkali (P10), cellulase (C), acid + cellulase (P2 + C), and alkali + cellulase (P10 + C) on dextran sodium sulfate-induced acute colitis. The physiological and histopathological indicators revealed that the alleviating effects were most significant for P10 + C, followed by P10, P2 + C, P2, and C. P10 + C increased the diversity and relative abundance of Akkermansia, leading to increased generation of colonic short-chain fatty acids as well as mRNA and protein expressions of GPR43, GPR109A, claudin-1, ZO-1, and occludin. Therefore, proinflammatory cytokines were decreased, and anti-inflammatory cytokines were increased. A compact conformation of P10 + C contributed to the alleviation effects on acute colitis. Alkali + cellulase-extracted orange pectin with a compact conformation has potential as adjuvant treatment for intestinal inflammation.
Keywords: acute colitis; extraction; gut microbiota; orange pectin; signaling pathway; structure.