Structural characterization of a water-soluble purple sweet potato polysaccharide and its effect on intestinal inflammation in mice

Abstract

• A water-soluble polysaccharide (WPSPP-1) was isolated from purple sweet potato. • WPSPP-1 was mainly composed of →4)-α-D-Glc p- (1→ and →4,6)-α-D-Glc p- (1→. • WPSPP-1 could improve inflammatory lesions in vivo . • WPSPP-1 could adjust microbial diversity caused by intestinal inflammation. A water-soluble polysaccharide (WPSPP-1) was isolated from purple sweet potato. The chemical structures of WPSPP-1 were characterized by high performance size-exclusion chromatography, methylation analysis, and 1D ( 1 H, 13 C) and 2D NMR spectra. Results showed the molecular weight of WPSPP-1 were 103 kDa. Monosaccharide analysis revealed WPSPP-1 consisted of glucose and mannose in the molar ratio of 20.44:1.00. The backbones of WPSPP-1 were composed of 1,6-α-D-Glc p , 1,4-α-D-Glc p , 1,2-α-D-Man p and 1,4,6-α-D-Glc p with β-D-Glc p on the branches. In vivo anti-inflammatory effect of WPSPP-1 on dextran sulfate sodium (DSS)-induced inflammatory mice was also determined. Results indicate that WPSPP-1 could improve inflammatory lesions by increasing IL-10, SOD and T-AOC levels and decreasing IL-1β, TNF-α, IL-6 and MDA levels. In addition, the consumption of WPSPP-1 adjusted the reduction of microbial diversity caused by intestinal inflammation, and restored the microbiota of the enteritis model group close to normal level.