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- β 1,3- d -GalNAc 4S6S repeating disaccharide backbone was substituted by monosaccharide branches comprising of Fuc 2S4S , Fuc 3S4S and Fuc 4S , linked to O-3 of d -GlcA. For the prevailing Fuc 3S4S 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 3S4S ) and Stichopus variegatus (SvFG, branched with Fuc 2S4S ). The result suggested that d -GlcA substituted with Fuc 3S4S was more susceptible to depolymerization than that with Fuc 2S4S . It might be due to the larger steric hindrance effects from Fuc 2S4S 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.