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The elucidation of the precise structure of fucan sulfate is essential for understanding the structure-activity relationship and promoting potential biomedical applications. In this work, the structure of a distinct fucan sulfate fraction V (PmFS in Ref 15 and FSV in Ref 16 → PFV) from Pattalus mollis was investigated using an oligosaccharide mapping approach. Six size-homogeneous fractions were purified from the mild acid hydrolyzed PFV and identified as fucitols, disaccharides and trisaccharides by 1D/2D NMR and MS analysis. Significantly, the sulfation pattern, glycosidic linkages, and sequences of all the oligosaccharides were unambiguously identified. The common 2-desulfation of the reducing end residue of the oligosaccharides was observed. Overall, the backbone of PFV was composed of L-Fuc 2S (major) and L-Fuc 3S (minor) linked by α1,4 glycosidic bonds. Importantly, the branches contain both monosaccharide and disaccharide linked to the backbone by α1,3 glycosidic linkages. Thus, the tentative structure of natural PFV was shown to be {-(R -α1,3)-L-Fuc 2S -α1,4-(L-Fuc 2S/3S -α1,4) x -} n , where R is L-Fuc (2S)4S -α1,3/4-L-Fuc 4S(0S) - or L-Fuc (2S)4S -. Our results provide insight into the heterogeneous structure of the fucan sulfate found in sea cucumbers. Additionally, PFV and its fractions showed strong anticoagulant and anti-iXase activities, which may be related to the distinct structure of PFV. [Display omitted] • A distinct fucan sulfate was investigated using an oligosaccharide mapping approach. • The structures of oligosaccharides were unambiguously identified. • The structure of the mainchain and the branches of PFV has been revised. • PFV displayed strong anticoagulant and anti-iXase activities. [ABSTRACT FROM AUTHOR]

Abstract: A process of depolymerization of a new fucosylated chondroitin sulphate from Thelenata ananas by free-radicals was developed. The fractions with different molecular weights and a narrow molecular weight distribution was obtained. The products were characterised by physicochemical properties, FT-IR spectra and NMR spectra. The results confirm the retention of primary structure of the fractions after the depolymerization. Furthermore, the anticoagulant activity of the fractions was evaluated by the activated partial thromboplastin time (APTT). The APTT activity decreases in proportion to the molecular weight following a logarithmic-like function, and the potentiating of prolongation of APTT activity requires at least an oligosaccharide chain of about 6–8 units (6000–7000Da). Compared to high doses of low molecular weight heparin (LMWH), a more desirable molecular weight fraction (13,950Da) demonstrates significantly lower anticoagulant activity. Thus, the fraction has more potential as an antithrombotic agent with reduced bleeding risk relative to LMWH. [Copyright &y& Elsevier]

Abstract: A process of depolymerization of a new fucosylated chondroitin sulfate from Thelenata ananas by free radicals was developed. The fractions with different molecular weights and narrow molecular weight distribution were obtained. The parameters of the process were investigated by high-performance gel permeation chromatography. The kinetics of the depolymerization of THG by H2O2 was studied, and a possible mechanism was proposed. The results indicated that the levels of final products fragmentation and reproducibility were different depending on the conditions of depolymerization used. The fragmentation of the main chain of THG occurred randomly and obeyed pseudo-first-order kinetics, and produced species with rather narrow and unimodal distribution of molar mass. Chemical compositions of partially depolymerized samples by 1H/13C nuclear magnetic resonance spectroscopy and by elementary analyzer suggested that there was no preferential cleavage of sulfated α-l-fucopyranose side-chain, and chemical composition of products was kept almost unchanged from that of native THG. [Copyright &y& Elsevier]

Abstract: A glycosaminoglycan from sea cucumber Thelenata anana (THG) was isolated as a polymer of molecular weight of around 70kDa. Its low molecular weight derivatives were first prepared by free radical depolymerization with hydrogen peroxide in the presence of copper(II) ion. The parameters of the process were investigated by a high-performance gel permeation chromatography. Analyses of chemical composition and molecular weight distribution indicated that the fragmentation of the main-chain of THG occurred randomly, obeyed pseudo first-order kinetics, and produced species with rather narrow and unimodal distribution of molar mass. The characterization of different molecular weight fractions was investigated by using viscometry and atomic force microscopy (AFM). Analysis of molecular weight and intrinsic viscosity in terms of the known theories for unperturbed wormlike cylinder yielded 1201±110nm−1, 15.3±1.5nm, and 1.5±0.3nm for molar mass per unit contour length M L, persistence length q, and diameter d, respectively. The M L and d values were approximately consistent with those observed by AFM. The present data suggest that THG may dissolve in 0.1M aqueous NaCl as single-stranded helical chains. [Copyright &y& Elsevier]

Fucan sulfates from echinoderm possess characteristic structures and various biological activities. Herein, comprehensive methods including enzymolysis, ion-exchange chromatography and size exclusion chromatography lead to the purification of five fucan sulfates (FSI, FSII, FSIII, FSIV, FSV) from the sea cucumber Pattalus mollis. Chemical composition analysis showed that they were all composed of l -fucose. Their sulfate content was determined by a conductimetric method. The molecular weight (Mw) of FSI, FSII, FSIII, FSIV and FSV were measured as 238.3 kDa, 81.0 kDa, 82.0 kDa, 23.2 kDa and 6.12 kDa, respectively. Detailed NMR spectroscopic analysis revealed that the structural sequence of FSI and FSII was →3)- l -Fuc S -α(1→, where Fuc S were Fuc 2S4S (10%), Fuc 2S (44%), Fuc 0S (10%), Fuc 4S (36%), that of FSIII was →4)- l -Fuc 2S -(α1 → 4)- l -Fuc 2S -(α1 → 4)- l -Fuc 0S/3S -(α1→, where Fuc 0S and Fuc 3S were in equal molar, and that FSIV was →4)- l -Fuc 2S3S -(α1 → 4)- l -Fuc 2S3S -(α1 → 4)- l -Fuc 2S -(α1→4)- l -Fuc 2S -(α1 → 4)- l -Fuc 2S -(α1 → 4)- l -Fuc 2S -(α1 →. This is the first report that such a diversity of fucan sulfates were obtained from the same sea cucumber species. Biological activity showed that FSI, FSII, FSIII and FSIV exhibited potent anticoagulant by prolonging the APTT. Among them, FSII, FSIII and FSIV showed the similar potency, while FSI owned the strongest. Structure-activity relationships analysis showed that molecular weight and sulfation degree should be the crucial factors for the activity. • Five fucan sulfates were purified from sea cucumber Pattalus mollis. • The physicochemical properties of four fucan sulfates were characterized. • Structural unit of FSI and FSIII was →3)- l -Fuc S -α(1→ and →4)- l -Fuc 2S -(α1→4)- l -Fuc 2S -(α1→4)- l -Fuc 0S/3S -(α1→, respectively. • FSIV was composed of an α1,4-linked hexafucose repeating unit. • FSI exhibit strong inhibition of the intrinsic coagulation pathway. [ABSTRACT FROM AUTHOR]

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-Fuc 3S4S -(α1 → 3)]-D-GlcA-(β1 → 3)-D-GalNAc 4S6S -(β1 → and →4-L-Fuc-(3SO 3 −)-α1→, respectively. The primary structure of SFI was →3)-L-Fuc 2S4S -(α1 → 4)-L-Fuc-(α1 → 3)-L-Fuc 2S -(α1 → 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. • Four sulfated polysaccharides were purified from the sea cucumber H. fuscopunctata. • The physicochemical properties of these polysaccharides were characterized. • The depolymerization methods could facilitate to separate sulfated polysaccharides. • The anticoagulant activities of these polysaccharides were evaluated. [ABSTRACT FROM AUTHOR]

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 -Fuc p -(3 S O 3 − )-1→, →4-α- l -Fuc p -(2 S O 3 − )-1→ and →3-α- l -Fuc p -(2 S O 3 − )-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. [ABSTRACT FROM AUTHOR]

Sulfated polysaccharides such as fucosylated glycosaminoglycan and fucan sulfate from echinoderm possess complex chemical structure and various biological activities. The two sulfated polysaccharides were purified from the low-value sea cucumber Holothuria coluber . Their physicochemical properties and chemical structures were analyzed and characterized by chemical and instrumental methods. Structural analysis clarified that the sea cucumber fucosylated glycosaminoglycan contains a chondroitin sulfate-like backbone and fucosyl branches with four various sulfation patterns. The fucan sulfate with molecular weight of 64.6 kDa comprises a central core of regular α(1 → 4)-linked tetrasaccharide repeating units, each of which is linked by a 4- O -sulfated fucose residue. Anticoagulant assays indicated that these sulfated polysaccharides possessed strong APTT prolonging activities and intrinsic factor Xase inhibitory activities, both of which decreased with the reduction of their molecular weights. Our results expand knowledge on the structural types of sulfated polysaccharides from sea cucumbers and further illustrate their functionality. [ABSTRACT FROM AUTHOR]

A fucan sulfate was isolated and purified from the sea cucumber Holothuria albiventer by papain enzymolysis, alkaline hydrolysis and ion-exchange chromatography. The water-soluble polysaccharide had high molecular weight and contained fucose and sulfate in a molar ratio of about 1:0.83. Methylation analysis of the native polysaccharide indicated that its glycosidic linkages and sulfate substituents might be at O- 3 or O -3, 4 or O -2, 3, or O -2, 3, 4 positions. FT-IR and 2D NMR spectroscopies further revealed that the fucan sulfate is characteristically composed of a regular α (1 → 3) linked hexasaccharide repeating unit which is substituted with sulfate esters in a distinctive pattern. Anticoagulant properties of the fucan sulfate and its depolymerized product were assessed in vitro in comparison with a low-molecular-weight heparin. The fucan sulfate exhibits strong APTT and TT prolonging activities and intrinsic factor Xase inhibitory activity, and its molecular size seemed to be required for these activities. [ABSTRACT FROM AUTHOR]

The digestibility of fucosylated glycosaminoglycan (FG) and its effects on digestive enzymes were investigated using an in vitro digestion model. Results showed that the molecular weight and the reducing sugar content of FG were not significantly changed, and no free monosaccharides released from FG were detected after the salivary, gastric and intestinal digestion, indicating that both the backbone and the sulfated fucose branches of FG are resistant to be cleaved in the saliva and gastrointestinal tract environments. Furthermore, FG can dose-dependently inhibit digestive enzymes such as α-amylase, pepsin and pancreatic lipase in different degrees under the simulated digestion conditions due to the sulfate and carboxyl groups. These physiological effects of FG may help control the postprandial glucose concentration and have the potential in the prevention or treatment of reflux disease and obesity. The findings may provide information on the digestibility and beneficial physiological effects of FG as a potential natural product to promote human health. [ABSTRACT FROM AUTHOR]

• Structural refinement of fucan sulfate from Stichopus herrmanni (Sh FS) was employed. • 21 oligosaccharides were elucidated from the mild acid hydrolysate of Sh FS. • Factors and depolymerization mechanism of mild acid hydrolysis were analyzed. • Moderate saccharide chain conferred potent anticoagulant and anti-thrombin activities. Fucan sulfate (FS) from sea cucumbers possesses linear sequences with repeating units that differ principally in the pattern of sulfation and position of glycosidic linkage. FS from Stichopus herrmanni (Sh FS) was preliminarily identified as the relatively simple structure {-3)-L-Fuc 2S -(α1-}n. Herein, mild acid hydrolysis was employed on Sh FS to yield 21 oligosaccharides. Analyses on their structures complemented the features of Sh FS to refine its spectral signal assignments. Combining with the methylation analysis, unit L-Fuc 2S4S was determined as the micro-component in its intact structure. The irregularity came from minor sulfation on O-4. Temperature and acid concentration were the critical parameters to the depolymerization and formation of oligosaccharides. Meanwhile, a three-step cleavage of the hydrolysis mechanism involving the partial O-2 de-sulfation and preferential cleavage between Fuc 0S and Fuc 2S4S was proposed. Bioactivity assays revealed that the Mw 15–16 kDa conferred the potent anticoagulation via inhibiting the thrombin activity mediated by heparin cofactor II. [ABSTRACT FROM AUTHOR]

Highlights: [•] DFG with the anhydro-d-talose units at new reducing ends was obtained by degradation. [•] The reaction conditions of the deacetylation and deaminative cleavage were investigated. [•] The chemical structures of DFGs such as sulfated fucose chains may remain stable. [•] Decreasing of molecular weight (M w) may weaken the anticoagulant activity in vitro. [•] M w might not affect inhibition of factor Xase and HCII-mediated inhibition of thrombin. [ABSTRACT FROM AUTHOR]

Abstract: Fucosylated chondroitin sulfate (FuCS) is a glycosaminoglycan from sea cucumber, made up of alternating β-d-glucuronic acid and N-acetyl-β-d-galactosamine units. The β-d-glucuronic acid residues have branches of sulfated fucose, while the fucose branches may have distinguishable patterns and proportions of sulfate substitution. The structure of the sulfated fucose branches of the fucosylated chondroitin sulfate from the sea cucumber Thelenata ananas has been characterized by mild acid hydrolysis and NMR technology. The results showed that the fucose residues are made up of 3-,4-mono-O-sulfated fucose and 2,4-di-O-sulfated fucose with about 25:22:53, respectively. The sulfated fucose branches are essential for the anticoagulant action of FuCS, and this potent effect is possibly related to the occurrence of 2,4-di-O-sulfated fucose units. Furthermore, these branches could constitute the structural requirement for the binding of the glycosaminoglycan to coagulant enzymes, such as thrombin by HCII, factor X by the intrinsic tenase complex. [Copyright &y& Elsevier]