Digestibility of sulfated polysaccharide from the brown seaweed Ascophyllum nodosum and its effect on the human gut microbiota in vitro

Sulfated polysaccharides from marine algae exhibit various bioactivities with potential benefits for human health and well-being. In this study, the in vitro digestibility and fermentability of polysaccharides from the brown seaweed Ascophyllum nodosum (AnPs) were examined, and the effects of AnPs on gut microbiota were determined using high-throughput sequencing technology. Salivary amylase, artificial gastric juice, and intestinal juice had no effect on AnPs, but the molecular weight of AnPs and reducing sugar decreased significantly after fermentation by gut microbiota. AnPs significantly modulated the composition of the gut microbiota; in particular, they increased the relative abundance of Bacteroidetes and Firmicutes, suggesting the potential for AnPs to decrease the risk of obesity. Furthermore, the total SCFA content after fermentation increased significantly. These results suggest that AnPs have potential uses as functional food components to improve human gut health.