Grafting of syringic acid onto fucoidan: Enhanced functional properties and therapeutic potential in histamine-induced liver injury

This study explores the grafting of syringic acid onto fucoidan and assesses the resultant graft's (F S) enhanced functional properties and therapeutic potential in a histamine-induced liver injury model. Utilizing a redox system of ascorbic acid and hydrogen peroxide, the grafting process achieved a grafting rate of 290.45 mg CAE/g, confirmed through UV–Vis spectroscopy, FT-IR spectroscopy, scanning electron microscopy, and thermogravimetric analysis. In vivo investigations using histamine-sensitive mice demonstrated that F S significantly mitigated histamine-induced damage, evidenced by improvements in body weight, organ index, and colon length. F S exhibited superior efficacy in restoring liver function indices (ALT, AST, ALP, GGT), enhancing antioxidant defenses (GSH, SOD), and reducing oxidative stress markers (MDA). Anti-inflammatory effects included reduced levels of pro-inflammatory cytokines (TNF- α , IL-6, IL-1 β ) and modulation of apoptosis-related proteins (BCl 2 , BAX). Additionally, F S upregulated key antioxidant genes in the Nrf2/KEAP1 pathway and downregulated inflammatory genes in the NF- κ B pathway. Restoration of colonic tight junction proteins (ZO-1, Occludin, Claudin-1) and normalization of gut microbiota composition further underscored the therapeutic potential of F S. The study highlights the significant enhancement in functional properties of fucoidan through SA grafting, presenting F S as a promising candidate for developing functional foods and nutraceuticals aimed at preventing and mitigating liver damage and related disorders.