Purification, structural characterization and anticoagulant activities of four sulfated polysaccharides from sea cucumber Holothuria fuscopunctata.

Sulfated polysaccharides from sea cucumber possess unique chemical structure and various biological activities. In this study, four sulfated polysaccharides were purified from the body wall of Holothuria fuscopunctata by anion exchange chromatography and chemical depolymerization. They were identified as sulfated fucan (SFI, SFII), fucosylated chondroitin sulfate (FCS) and sulfated aminoglycan (AG) by physicochemical and structural analyses. The Mw of SFI, SFII, FCS and AG were 470.6, 36.8, 42.6, 39.6 kDa and the sulfate content was 21.40%, 35.86%, 33.70%, 35.70%, respectively. Their primary structures were clarified both by monosaccharide composition and 1D/2D NMR spectroscopy analysis. As a result, the repeating sequences of FCS and SFII were →4)-[L-Fuc3S4S-(α1 â†’ 3)]-D-GlcA-(ß1 â†’ 3)-D-GalNAc4S6S-(ß1 â†’ and →4-L-Fuc-(3SO3-)-α1→, respectively. The primary structure of SFI was →3)-L-Fuc2S4S-(α1 â†’ 4)-L-Fuc-(α1 â†’ 3)-L-Fuc2S-(α1 â†’ 4)-L-Fuc-(α1→. The sulfated AG was composed of four types of monosaccharides. Their anticoagulant activities were further evaluated in vitro. FCS and AG showed potent anticoagulant activity and intrinsic factor Xase inhibition activity. These results expand the knowledge on the structure types of sulfated polysaccharides from sea cucumber and further illustration of their functionality.

Structural analysis and anticoagulant activities of three highly regular fucan sulfates as novel intrinsic factor Xase inhibitors.

Fucoidan or fucan sulfate, a sulfated polysaccharide from algae or echinoderm mainly containing fucoses, possesses complex chemical structure and various biological activities. Herein, three fucan sulfates consisted of distinctive simplest repeating units were isolated from Holothuria fuscopunctata, Thelenota ananas and Stichopus horrens. The structural sequences of these fucan sulfates from H. fuscopunctata, T. ananas and S. horrens are →4-α-l-Fucp-(3SO3-)-1→, →4-α-l-Fucp-(2SO3-)-1→ and →3-α-l-Fucp-(2SO3-)-1→, respectively, revealing the existence of the highly regular homogeneous fucan sulfates and their structural diversity in the sea cucumber species for the first time. Pharmacological assays indicated their specific sulfation pattern and position of the glycosidic linkage may contribute to the anticoagulant action. Further mechanism analysis suggested that these fucan sulfates may exhibit strong inhibition of the intrinsic coagulation pathway by targeting the intrinsic coagulation factor Xase. Our results provide novel information to enrich knowledge on structural types of fucan sulfate and to illustrate its functionality.