Therapeutic potential of seaweed extracts: In vitro and in vivo studies on alleviating inflammation and enhancing intestinal barrier function.

Rich in diverse compounds such as polysaccharides, pigments, and phenols, seaweed offers not only nutritional benefits but also functional elements such as fucoidan, which demonstrates anticoagulant, anticancer, and anti-inflammatory properties. This investigation screened 22 seaweed extracts obtained using either water or ethanol as solvents from a total of fourteen seaweed species to evaluate their potential as dietary supplement ingredients. In inflammation-induced Caco-2 cell models, Saccharina japonica, Capsosiphon fulvescens, Hizikia fusiforme, and Chondrus ocellatus exhibited a significant increase in TEER values 24 h after treatment with seaweed extracts, in contrast to the cocktail group (p < 0.05). Additionally, permeability significantly decreased compared to the cocktail group (p < 0.05). Notably, these species exhibited a reduction in mRNA expression of TNF-alpha and iNOS, coupled with an elevation in the protein expression of tight junction proteins. Moreover, when tested in DSS-induced mice, these seaweeds demonstrated enhancements in colon health indices, suggesting their potential as beneficial treatments for inflammatory bowel diseases and associated conditions. This study demonstrates the therapeutic promise of these four seaweed species and emphasizes their prospective role in treating inflammatory bowel diseases, urging further exploration of their therapeutic mechanisms and clinical applications.