Isolation,purification and structural characterization of a water-soluble polysaccharide HM41 from Halenia elliptica D. Don

A water-soluble polysaccharide, HM₄₁, was obtained from Halenia elliptica D. Don by acidic ethanol fractionation and gel filtration. Its homogeneity was confirmed by chromatography using multiple systems. HM₄₁ was composed of rhamnose (Rha), arabinose (Ara), xylose (Xyl), mannose (Man), galactose (Gal), glucose (Glc) with a molar ratio of 1.0:5.5:1.8:3.0:9.4:21. The average molecular weight of HM₄₁ was approximately 1.17 × 10⁴ . Periodate oxidation, Smith degradation, methylation and GC, IR, NMR, XRD, GC-MS analysis were used for the structural analysis of HM₄₁. Its main chain was composed mainly of β-(1→4)Gal, β-(1→4)Glc and β-(1→6)Glc. β-(1→4)Gal were substituted at 6-O and on average there were 14 branches among 23 main chain residues; (1→4)Glc had no branch; (1→6)Glc were substituted at 3-O and on average there were 9 branches among 14 main chain residues. The side chain was composed of (1→3,6)-Rha, (1→4)/(1→5)-Ara, (1→4)/(1→5)-Xyl, (1→4,6)-Man and (1→2)-Glc. The terminal residue was composed of Ara, Xyl, Man, Gal, and Glc. Then, we demonstrated that HM and HM₄₁ had strong scavenging activities in vitro hydroxyl. Overall, HM and HM₄₁ may have potential applications in the antioxidants for medical and food industry.