Anti-inflammatory activity of iota-carrageenan oligosaccharide in vivo/vitro: Mechanistic insights

The biological activities of marine algal oligosaccharides (MAOs) have garnered widespread attention today. Compared with κ-carrageenase and its enzymatic hydrolysates, the research on ι-carrageenase and its enzymatic hydrolysates is still in its infancy. In this study, the ι-carrageenan oligosaccharide, ι-COs-L (DP2, DP4) and ι-COs-H (DP8) prepared by ι-carrageenase Car1293, dose-dependently suppressed the overexpression of TNF-α, IL-6, IL-1β, and NO while improve the expression of TGF-β1 and IL-10 in lipopolysaccharide-induced RAW264.7 inflammation model and exerted excellent anti-inflammatory effect via NF-κB/IκBα signaling pathway Moreover, different concentrations of ι-COs-H effectively alleviated DSS-induced colitis symptoms in mice by modulating gut microbiota composition, promoting short-chain fatty acid (SCFA) production, and enhancing intestinal barrier function. Transcriptomic and Western blot analyses indicated that the gut microbiota-SCFA-PPARγ axis plays an important role in the maintenance of intestinal homeostasis, which may represent a potential approach for colitis prevention by ι-carrageenan oligosaccharide.