NMR characterization and anticoagulant activity of the oligosaccharides from the fucosylated glycosaminoglycan isolated from Holothuria coluber.

A glycosaminoglycan was isolated from the sea cucumber Holothuria coluber (HcFG). A series of oligosaccharide fragments (dp range 3-11) were prepared from its β-eliminative depolymerized product (dHcFG). Extensive NMR characterization of the oligosaccharides indicated the d-GlcA-β1,3-d-GalNAc repeating disaccharide backbone was substituted by monosaccharide branches comprising of Fuc, Fuc and Fuc, linked to O-3 of d-GlcA. For the prevailing Fuc at nonreducing end of dHcFG, the β-eliminative depolymerization process of HcFG was compared with those of the FGs from Actinopyga miliaris (AmFG, branched with Fuc) and Stichopus variegatus (SvFG, branched with Fuc). The result suggested that d-GlcA substituted with Fuc was more susceptible to depolymerization than that with Fuc. It might be due to the larger steric hindrance effects from Fuc on the esterification of GlcA. Biological assays confirmed that the minimum chain length (dp8), regardless of the Fuc branch types, was required for the potent anti-iXase and anticoagulant activities in FG fragments.