A fructan-type polysaccharide from Lycium ruthenicum attenuates liver fibrosis via microbiota-dependent ferroptosis inhibition.

Plant-derived polysaccharides represent promising candidates for hepatic fibrosis (HF) therapy through the gut-liver axis. This study investigated the structural characteristics, anti-fibrotic efficacy, and mechanisms of LRMP1, a novel polysaccharide from Lycium ruthenicum Murr. LRMP1 was identified as a homogeneous inulin-type fructan (3.055 kDa) with a → 1)-β-D-Fruf-(2 → backbone terminated by α-D-Glcp-(1 → 2)-β-D-Fruf linkages (DP 4-20). Integrated multi-omics analysis combining hepatic transcriptomics, serum metabolomics, and gut microbiome profiling revealed that LRMP1 ameliorates HF via a gut microbiota-postbiotics-ferroptosis regulatory axis. In both CCl4-induced and MCD diet-induced chronic fibrosis models, LRMP1 significantly attenuated liver injury, fibrosis, inflammation, and oxidative stress, while restoring intestinal barrier integrity. These protective effects correlated with enrichment of beneficial bacteria (Akkermansia muciniphila, Lactobacillus spp.) and pathogen depletion. Mechanistically, LRMP1 suppressed TGF-β signaling and inhibited hepatocyte ferroptosis by restoring the GPX4/SLC7A11 antioxidant system and reducing lipid peroxidation. Serum metabolomics further revealed elevated anti-ferroptotic metabolites and suppressed pro-inflammatory lipids. Crucially, antibiotic depletion abolished LRMP1's efficacy, whereas fecal microbiota transplantation and fermentation supernatant experiments confirmed that microbiota-derived postbiotics selectively protect hepatocytes from ferroptosis. These findings establish LRMP1 as a promising microbiota-targeted polysaccharide for HF intervention through the gut-liver axis.