Advances in Chemical Composition and Structure of Sulfated Polysaccharides from Sea Cucumber

Fucosylated chondroitin sulfate (FCS) and fucoidan (FUC) from sea cucumber are a class of fucose-rich sulfated polymers with a complex structure found in the body wall of sea cucumber. Previous studies have demonstrated that the backbone of FCS is composed of β-D-glucuronic acid and β-D-acetylgalactosamine, whose branched chains are composed of L-fucoses of different degrees of polymerization, and that the backbone of FUC is mainly composed of α-L-fucose. Both sulfated polysaccharides contain a small amount of other monosaccharides. Sulfate groups are mainly located at positions C-4, C-6 or C-4,6 of D-acetylgalactosamine in the main chain and at positions C-4, C-3,4 or C-2,4 of L-fucose in the branched chains of FCS, and located at C-2, C-4 or C-2,4 of L-fucose in FUC. Therefore, the structures of both sulfated polymers are highly heterogeneous. The currently available techniques for structural analysis of FCS and FUC mainly include methylation analysis, two-dimensional nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Here, we give an up-to-date review on the chemical composition, structural features and common analytical techniques of sea cucumber sulfated polysaccharides. We hope this review would provide useful information for future studies on the structural analysis and structure-activity relationship of sea cucumber sulfated polysaccharides.