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

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 (H-1, C-13) 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-alpha-D-Glcp, 1,4-alpha-D-Glcp, 1,2-alpha-D-Manp and 1,4,6-alpha-D-Glcp with beta-D-Glcp 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-1 beta, TNF-alpha, 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.