Structural characterization of polysaccharides from Hyriopsis cumingii

The structural characterization of purified Hyriopsis cumingii polysaccharides (HCPS) were studied by using periodic acid oxidation, Smith degradation, methylation combined with HPLC, GC, GC–MS, FTIR and NMR spectra. Results showed that sugar rings of purified HCPS were pyranose rings. In HCPS-1 and HCPS-2, glycosyl residues were linked mainly by α-configuration glycosidic bond. As to HCPS-3, sugar residues were connected by α- and β-configuration glycosidic bonds. Number of glycosyl residues in one repeat unit was 7, 9 and 10 for HCPS-1, HCPS-2 and HCPS-3 respectively. Backbone chains of purified HCPS were linked by 1 → 4 glycosidic bonds. In HCPS-1 and HCPS-2, there were one backbone chain and two branch chains (one linked by 1 → 3 glycosidic bond, another connected by 1 → 6 glycosidic bond) in one repeat unit. As to HCPS-3, three branch chains (two connected by 1 → 3 glycosidic bond, one linked by 1 → 6 glycosidic bond) were attached to backbone chain in one repeat unit.