Structural characterization and human gut microbiota fermentation in vitro of a polysaccharide from Fucus vesiculosus.

In this study, an acidic polysaccharide (FVP-7 A) was isolated from Fucus vesiculosus by DEAE-Sepharose™ fast flow. The chemical composition, glycosidic bonds and in vitro fecal fermentation characteristics of FVP-7 A were studied. Results shown that FVP-7 A was a homogenous polysaccharide with average molecular weight of 30.94 kDa. Combined with FT-IR, monosaccharide composition, methylation and NMR analysis, the glycosidic bonds of FVP-7 A mainly composed of →4)- β -D-Man p -(1→, →3)- α -L-Fuc p -(1→, α -D-Man p -(1→, →3)- β -D-Man p -(1 → and →4,6)- α -D-Man p -(1→. The zeta potential and atomic force microscopy images indicated that FVP-7 A could exist stably as a single chain-like structure in dilute solution. After gut fermentation, FVP-7 A was utilized and promoted multiple short-chain fatty acids production, especially acetic acid, butyric acid and valeric acid. For prebiotics, FVP-7 A significantly increased the relative abundance of short-chain fatty acids producing bacteria such as Bacteroides , Lachnospira , Faecalibacterium , Ruminococcus , Oscillospira and Dialister , and inhiited the growth of the harmful bacteria Shigella. These results indicated that FVP-7 A could be used as a potential dietary supplement to improve intestinal health. [Display omitted] • A novel heteropolysaccharide (FVP-7 A) was purified from Fucus vesiculosus. • Its glycosidic bonds mainly consisted of →4)- β -D-Man p -(1→, →3)- α -L-Fuc p -(1→, α -D-Man p -(1→, →3)- β -D-Man p -(1 → and →4,6)- α -D-Man p -(1 →. • FVP-7 A was molecularly dispersed in water to adopt chain-like shape. • FVP-7 A could modulate the richness and community structure of gut microbiota. [ABSTRACT FROM AUTHOR]