Two Laminaria japonica polysaccharides with distinct structure characterization affect gut microbiota and metabolites in hyperlipidemic mice differently

Our previous study found dietary mannogluconic acid (MA) and fucogalactan sulfate (FS) from Laminaria japonica have distinct structure characterization and potential hypolipidemic effects in vitro. Herein, we compared the benefits of MA and FS on hyperlipidemia. The result showed only FS treatment decreased body weight and serum cholesterol levels. Compared with MA, FS was more effective in mitigating hepatic fat accumulation, promoting GSH-Px activity, reducing the MDA formation, and lowering the level of TNF-α in liver. Gut microbiota and metabolism analysis revealed that FS increased the relative abundance of beneficial bacteria and boosted the level of short chain fatty acids. Particularly, taurine and 3α,7α,12α-trihydroxy-24-oxo-5-β-cholestanoyl CoA were upregulated by FS, which might attribute to the increased Oscillibacter and thus affect the enterohepatic circulation of bile acids and serum TC level. Therefore, FS with more branches and sulfate ester groups could be a good lipid-lowering dietary supplement.