Oligomer-guided recognition of two fucan sulfate from Bohadschia argus and inhibition of P-selectin binding to its ligand

Unique structure and biological properties of fucosylated glycosaminoglycan and its oligosaccharides from sea cucumber Holothuria floridana

Fucosylated glycosaminoglycan (FG) from Holothuroidea exhibits notable structural diversity and multiple biological activities. This study investigated the HfFG isolated from the sea cucumber Holothuria floridana, focusing on its chemical structure and biological activities. Structural analysis of eleven oligosaccharides (a-k) and a depolymerized product (dHfFG-II) using NMR identified the HfFG backbone as chondroitin sulfate E (CS-E), with various branches, including L-Fuc2S4S, L-Fuc3S4S, L-Fuc4S, and the unique disaccharide D-GalNAc4S-α1,2-L-Fuc3S4S, attached at C-3 of GlcA. A high L-Fuc2S4S (40 %) and disaccharide branch (35 %) content allowed their contiguous distribution within the CS-E chain, as evidenced by the predominant hexasaccharides (i, j) in size-homogeneous Fr4 and the novel nonasaccharide k in Fr5. Notably, previously unreported branches and sequences in HfFG were confirmed, offering new understanding of the natural HfFG structure. HfFG showed potent inhibitory activities on the intrinsic tenase complex (iXase), heparanase, and P-selectin binding to PSGL-1. Depolymerization selectively modulated these activities, preserving anti-iXase potency while attenuating heparanase and P-selectin inhibition. These activities were dependent on oligosaccharide chain length and sequence. Comparing the activities of FG and its oligosaccharides highlights their potential for the rational design of targeted inhibitors of heparanase or P-selectin binding to PSGL-1, with significant implications for therapeutic applications.

Recent advances in fucoidan-based improved delivery systems: Structure, carrier types and biomedical applications

Consumer demand for nutritional supplements has fueled the rapid growth of the functional food market. However, ensuring the stability of functional factors in harsh environments remains a major challenge. The development of encapsulation systems is regarded as an effective method for enhancing the stability of functional factors, encapsulation carriers can offer protection for these functional factors. However, the selection of materials remains a significant constraint in the construction of delivery systems. Therefore, developing new encapsulation materials is crucial for advancing delivery systems, preserving the stability of functional factors, and ensuring public health. Fucoidan, a sulfated marine polysaccharide, has garnered significant attention in the field of encapsulation due to its notable advantages, including its remarkable bioactivity, biocompatibility, and targeted binding properties. Fucoidan-improved delivery systems provide new strategies for encapsulation of functional factors. This review first describes the structure of fucoidan, its modification and lists the applications of modified fucoidan, and assesses its feasibility for enhancing delivery systems. Second, it summarizes several common encapsulation technologies and methods, and outlines various carrier types based on fucoidan. Finally, it elucidates recent advances in the biomedical applications of fucoidan-improved delivery systems. Notably, it also presents the challenges and future prospects of this promising field.

A comprehensive review of sulfated fucan from sea cucumber: Antecedent and prospect

Sulfated fucan from sea cucumber is mainly consists of L-fucose and sulfate groups. Recent studies have confirmed that the structure of sulfated fucan mainly consists of repeating units, typically tetrasaccharides. However, there is growing evidence indicating the presence of irregular domains with heterogeneous units that have not been extensively explored. Moreover, as a key contributor to the nutritional benefits of sea cucumbers, sulfated fucan demonstrates a range of biological activities, such as anti-inflammatory, anticancer, hypolipidemic, anti-hyperglycemic, antioxidant, and anticoagulant properties. These biological activities are profoundly influenced by the structural features of sulfated fucan including molecular weight and distribution patterns of sulfate groups. The latest research indicates that sulfated fucan is dispersed in the extracellular matrix of the body wall of sea cucumbers. This article aimed to review the research progress on the in-situ distribution, structures, structural elucidation strategies, functions, and structure-activity relationships of sulfated fucan, especially in the last decade. It also provided insights into the major challenges and potential solutions in the research and development of sulfated fucan. Moreover, the fucanase and carbohydrate binding modules are anticipated to play pivotal roles in advancing this field.

Purification and Structural Analyses of Sulfated Polysaccharides from Low-Value Sea Cucumber Stichopus naso and Anticoagulant Activities of Its Oligosaccharides

Three polysaccharides (SnNG, SnFS and SnFG) were purified from the body wall of Stichopus naso. The physicochemical properties, including monosaccharide composition, molecular weight, sulfate content, and optical rotation, were analyzed, confirming that SnFS and SnFG are sulfated polysaccharides commonly found in sea cucumbers. The highly regular structure {3)-L-Fuc2S-(α1,}n of SnFS was determined via a detailed NMR analysis of its oxidative degradation product. By employing β-elimination depolymerization of SnFG, tri-, penta-, octa-, hendeca-, tetradeca-, and heptadeca-saccharides were obtained from the low-molecular-weight product. Their well-defined structures confirmed that SnFG possessed the backbone of {D-GalNAc4S6S-β(1,4)-D-GlcA}, and each GlcA residue was branched with Fuc2S4S. SnFS and SnFG are both structurally the simplest version of natural fucan sulfate and fucosylated glycosaminoglycan, facilitating the application of low-value sea cucumbers S. naso. Bioactivity assays showed that SnFG and its derived oligosaccharides exhibited potent anticoagulation and intrinsic factor Xase (iXase) inhibition. Moreover, a comparative analysis with the series of oligosaccharides solely branched with Fuc3S4S showed that in oligosaccharides with lower degrees of polymerization, such as octasaccharides, Fuc2S4S led to a greater increase in APTT prolongation and iXase inhibition. As the degree of polymerization increases, the influence from the sulfation pattern diminishes, until it is overshadowed by the effects of molecular weight.

The therapeutic effects of marine sulfated polysaccharides on diabetic nephropathy

Marine sulfated polysaccharide (MSP) is a natural high molecular polysaccharide containing sulfate groups, which widely exists in various marine organisms. The sources determine structural variabilities of MSPs which have high security and wide biological activities, such as anticoagulation, antitumor, antivirus, immune regulation, regulation of glucose and lipid metabolism, antioxidant, etc. Due to the structural similarities between MSP and endogenous heparan sulfate, a majority of studies have shown that MSP can be used to treat diabetic nephropathy (DN) in vivo and in vitro. In this paper, we reviewed the anti-DN activities, the dominant mechanisms and structure-activity relationship of MSPs in order to provide the overall scene of MSPs as a modality of treating DN.

Structural characterization of a distinct fucan sulfate from Pattalus mollis through an oligosaccharide mapping approach

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-Fuc2S (major) and L-Fuc3S (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-Fuc2S-α1,4-(L-Fuc2S/3S-α1,4)x-}n, where R is L-Fuc(2S)4S-α1,3/4-L-Fuc4S(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.