Sulfated Fucoidan Research Articles

Sulfated polysaccharide from Apostichopus japonicus viscera exhibits anti-inflammatory properties in vitro and in vivo

Polysaccharides from sea cucumbers are known for their biological activities, but little is known about those from sea cucumber viscera. The present study isolated a sulfated polysaccharide (SCVP-2) from the viscera of Apostichopus japonicas, which had a molecular weight of 209.1 kDa. SCVP-2 comprised 66.3 % total sugars, 2.1 % uronic acid, 4.5 % proteins, and 25.5 % sulfate groups, containing glucosamine, galactosamine, glucose, galactose, and fucose. FT-IR and NMR analyses identified SCVP-2 as a fucoidan sulfate with sulfation patterns of the fucose branches as Fuc2S, Fuc4S, and Fuc0S. SEM and AFM analyses showed irregular clusters and linear conformations. SCVP-2 demonstrated strong anti-inflammatory properties both in vitro and in vivo. In lipopolysaccharide (LPS)-induced inflammation in macrophage RAW264.7 cells, SCVP-2 significantly reduced nitric oxide (NO) and cytokine secretion (IL-1β, IL-6, TNF-α). Additionally, it downregulated the expression of these cytokine genes. Furthermore, the anti-inflammatory mechanism of SCVP-2 was related to the inhibition of the MAPKs and NF-κB pathways. SCVP-2's anti-inflammatory capacity was confirmed in acute inflammation models, including xylene-induced ear swelling and acetic acid-induced peritoneal capillary permeability, and in high-fat diet-induced systemic low-grade chronic inflammation. In conclusion, SCVP-2 exhibits significant anti-inflammatory activity, suggesting its potential for development as a functional food ingredient or therapeutic agent for inflammation-related diseases.

Alleviative effects of sulfated polysaccharide from Ishige Okamurae against DSS-induced ulcerative colitis via inhibiting inflammation and modulating gut microbiota

A water-soluble polysaccharide from the brown alga Ishige Okamurae, designated IOP-0, was obtained by preparative anion-exchange and size-exclusion chromatography. Chemical and spectroscopic investigations revealed that IOP-0 was a sulfated fucoidan with a backbone primarily composed of 3-linked and 4-linked-L-fucose with sulfate groups at C-2/C-4 of the 3-linked-L-fucose. The protective effect of IOP-0 on ulcerative colitis was evaluated in this work. The results showed that IOP-0 could significantly alleviate the symptoms of ulcerative colitis by preventing weight loss, preserving the structure of intestinal tissues, and ameliorating the dysregulation of inflammatory cytokines (TNF-α, IL-6, and IL-10). Meanwhile, IOP-0 protected the colonic mucosal barrier by promoting the tight junction protein ZO-1 and occludin expression. In addition, IOP-0 was able to maintain intestinal homeostasis and improve intestinal function by regulating the gut microbiota and their metabolites, such as short-chain fatty acids (SCFAs). These results suggest that IOP-0 might be a potential dietary supplement for the prevention and treatment of ulcerative colitis.

Targeting ferroptosis withnatural products inliver injury: new insights frommolecular mechanisms totargeted therapies.

Ferroptosis is a brand-new type of controlled cell death that is distinguished by its reliance on iron and the production of lipid peroxidation. The role of ferroptosis in damaging liver disorders has attracted a lot of attention in recent years. One effective strategy to reduce liver damage is to target ferroptosis. The purpose of this review is to clarify the connection between ferroptosis and liver damage and to look into the potential contribution of natural products to the clinical management of liver damage and the discovery of novel medications. To study the methods by which natural products operate on ferroptosis to cure liver damage and their main signaling pathways, we searched databases from the time of initial publication to August 2023 in PubMed, EMBASE, Web of Science, Ovid, ScienceDirect, and China National Knowledge Infrastructure. The liver illness that each natural product treats is categorized and summarized. It's interesting to note that several natural compounds, such Artemether, Fucoidan sulfate, Curcumin, etc., have the benefit of having many targets and multiple pathways of action. We saw that in human samples or animal models of liver injury, ferroptosis indicators were activated, lipid peroxidation levels were elevated, and iron inhibitors had the ability to reduce liver damage. Liver damage can be treated with natural products by regulating ferroptosis. This is mostly accomplished through the modulation of Nrf2-related pathways (e.g., Conclusions and Astaxanthin), biological enzymes like GPX4 and the SIRT family (e.g., Chrysophanol and Decursin), and transcription factors like P53 (e.g., Artemether and Zeaxanthin). This review proposes a promising path for the therapeutic therapy of liver damage by providing a theoretical foundation for the management of ferroptosis utilizing natural ingredients.

Structural and functional characterization of the novel endo-α(1,4)-fucoidanase Mef1 from the marine bacterium Muricauda eckloniae.

Fucoidanases (EC 3.2.1.-) catalyze the hydrolysis of glycosidic bonds between fucose residues in fucoidans. Fucoidans are a compositionally and structurally diverse class of fucose-containing sulfated polysaccharides that are primarily found in brown seaweeds. Here, the structural characterization of a novel endo-α(1,4)-fucoidanase, Mef1, from the marine bacterium Muricauda eckloniae is presented, showing sequence similarity to members of glycoside hydrolase family 107. Using carbohydrate polyacrylamide gel electrophoresis and nuclear magnetic resonance analyses, it is shown that the fucoidanase Mef1 catalyzes thecleavage of α(1,4)-linkages between fucose residues sulfated on C2 in the structure [-3)-α-L-Fucp2S-(1,4)-α-L-Fucp2S-(1-]n in fucoidan from Fucus evanescens. Kinetic analysis of Mef1 activity by Fourier transform infrared spectroscopy revealed that the specific Mef1 fucoidanase activity (Uf) on F.evanescens fucoidan was 0.1 × 10-3 Uf µM-1. By crystal structure determination of Mef1 at 1.8 Å resolution, a single-domain organization comprising a (β/α)8-barrel domain was determined. The active site was in an extended, positively charged groove that is likely to be designed to accommodate the binding of the negatively charged, sulfated fucoidan substrate. The active site of Mef1 comprises the amino acids His270 and Asp187, providing acid/base and nucleophile groups, respectively, for the hydrolysis of glycosidic bonds in the fucoidan backbone. Electron densities were identified for two possible Ca2+ ions in the enzyme, one of which is partially exposed to the active-site groove, while the other is very tightly coordinated. A water wire was discovered leading from the exterior of the Mef1 enzyme into the active site, passing the tightly coordinated Ca2+ site.

In-silico antiviral screening of native seaweed fucoidan and its derivatives against dengue virus-2 RNA dependant RNA polymerase (RdRp)

Dengue virus (DENV) infections are a major life threat around the globe with millions of people's life is at risk. The lack of Antidengue drugs and vaccines demands lead molecules for the treatment of Dengue infections. DENV-2 RNA Dependant RNA polymerase (RdRp) was designated as the prime target because of its major role in the viral replication cycle. The purpose of the study is to isolate fucoidan and perform logical and acceptable structural modification of fucoidan for the in-silico screening against DENV for the treatment of DENV DENV-2 NS5 RdRp 6IZY RdRp enzyme was selected for the research on antiviral drugs. The sulfated polysaccharide Fucoidan was derived from brown seaweed Stoechospermum marginatum. It was subjected to acid hydrolysis to yield low molecular weight fucoidan monomer and denoted as SMFUC. SMFUC was characterized by spectroscopic studies like FTIR, NMR, and Mass spectroscopy. The SMFUC molecule was designed to yield its derivatives by the structural modification of the two 2 methyl (–CH3) and two hydroxyls (–OH) of the native fucoidan. The methyl moieties were converted to the carboxyl group, and it was further converted to its ester, amide, aldehyde, acid chloride, and ketone, the hydroxyl groups were acetylated, benzoylated, and phosphorylated. Further, Desulphate SMFUC was designed for the Insilco docking, ADMET, MMSD, and Molecular dynamic study against DENV RdRp 6IZY. SMFUC SMFUC1, SMFUC2, SMFUC3, SMFUC4, and SMFUC5 showed ligand binding affinity GLIDE scores in the range of −5.03 to −7.67541 kcal/mol against DENV-2 RdRp 6IZY amongst the native fucoidan and its derivatives. SMFUC2 showed the highest ligand binding affinity of −7.657 kcal/mol. In-silico pharmacokinetic studies of these molecules were screened using SwissADME studies and sarADMET and it was proved that these compounds were well absorbed by the GI tract and do not cross the blood–brain barrier. Simulated toxicity simulation studies proved that except for aminated, sulfated fucoidans they are non-toxic and without a metabolic enzyme inhibition activity. A simulated molecular dynamics study against the optimized fucoidans showed an RMSD score of 1.5, which indicated the ideal interaction of the fucoidan against DENV-2 RdRp. Hence, it may be concluded that seaweed fucoidan and its derivatives have high antiviral potential against DENV-2 cell wall proteins. Hence these molecules might be a lead for the emergence of antiviral drugs against DENV-2 infections.

Fucoidan from Spatoglossum schröederi promotes B16-F10 malignancy features modulation and antimelanoma in vivo activities

Although recent advances in targeted and immunotherapy, metastatic melanoma treatment still poses as a challenge, with limited success and a variety of severe adverse effects. Polysaccharides from natural sources have been explored as a new approach to tackle cancer and melanoma treatment limitations, even reaching clinical trials. One prominent group of biological active polysaccharides are fucoidans - sulfated polysaccharides mainly constituted of fucose and obtained from brown seaweed. In the present study, we explored the antimelanoma activities of Fucan A, a highly sulfated fucoidan obtained from Spatoglossum schröederi. Fucan A presented a selective antiproliferative effect against murine melanoma B16-F10 cell line impacting cell cycle progression in concentrations of 100 and 1000 μg⸱mL−1 while also reducing its colony formation and invasive capacity, as well as modulating invasion mechanistically related genes - namely MMP-9, MMP-14, glypican-3 and perlecan. Fucan A also reduced in vivo solid tumor volume in a daily post-cell inoculation treatment regimen with a 100 mg⸱Kg−1 dosage. Additionally, using a 48 h pre-treatment regimen in a reduced dosage (30 mg⸱Kg−1), Fucan A reduced pulmonary metastasis colonization, with limited to non-detectable adverse effects. These results associated with the explorable commercial potential of S. schröederi indicate an interesting compound to be further explored as a possible antimelanoma drug.

Heparin and heparin proteoglycan-mimetics activate platelets via PEAR1 and PI3Kβ

BackgroundPlatelet endothelial aggregation receptor 1 (PEAR1) is a single-transmembrane orphan receptor primarily expressed on platelets and endothelial cells. Genetic variants of PEAR1 have repeatedly and independently been identified to be associated with cardiovascular diseases, including coronary artery disease. ObjectivesWe have identified sulfated fucoidans and their mimetics as ligands for PEAR1 and proposed that its endogenous ligand is a sulfated proteoglycan. The aim of this study was to test this hypothesis. MethodsA heparin proteoglycan-mimetic (HPGM) was created by linking unfractionated heparin (UFH) to albumin. The ability of the HPGM, UFH and selectively desulfated heparins to stimulate platelet aggregation and protein phosphorylation was investigated. Nanobodies against the 12th to 13th epidermal growth factor-like repeat of PEAR1 and phosphoinositide 3-kinase (PI3K) isoform-selective inhibitors were tested for the inhibition of platelet activation. ResultsWe show that HPGM, heparin conjugated to an albumin protein core, stimulates aggregation and phosphorylation of PEAR1 in washed platelets. Platelet aggregation was abolished by an anti-PEAR1 nanobody, Nb138. UFH stimulated platelet aggregation in washed platelets, but desulfated UFH did not. Furthermore, HPGM, but not UFH, stimulated maximal aggregation in platelet-rich plasma. However, both HPGM and UFH increased integrin αIIbβ3 activation in whole blood. By using PI3K isoform-selective inhibitors, we show that PEAR1 activates PI3Kβ, leading to Akt phosphorylation. ConclusionOur findings reveal that PEAR1 is a receptor for heparin and HPGM and that PI3Kβ is a key signaling molecule downstream of PEAR1 in platelets. These findings may have important implications for our understanding of the role of PEAR1 in cardiovascular disease.

Fucoidan and Alginate from the Brown Algae Colpomenia sinuosa and Their Combination with Vitamin C Trigger Apoptosis in Colon Cancer.

Brown seaweeds are producers of bioactive molecules which are known to inhibit oncogenic growth. Here, we investigated the antioxidant, cytotoxic, and apoptotic effects of two polysaccharides from the brown algae Colpomenia sinuosa, namely fucoidan and alginate, in a panel of cancer cell lines and evaluated their effects when combined with vitamin C. Fucoidan and alginate were isolated from brown algae and characterized by HPLC, FTIR, and NMR spectroscopy. The results indicated that highly sulfated fucoidans had higher antioxidant and cytotoxic effects than alginate. Human colon cancer cells were the most sensitive to the algal treatments, with fucoidan having an IC50 value (618.9 µg/mL−1) lower than that of alginate (690 µg/mL−1). The production of reactive oxygen species was increased upon treatment of HCT-116 cells with fucoidan and alginate, which suggest that these compounds may trigger cell death via oxidative damage. The combination of fucoidan with vitamin C showed enhanced effects compared to treatment with fucoidan alone, as evidenced by the significant inhibitory effects on HCT-116 colon cancer cell viability. The combination of the algal polysaccharides with vitamin C caused enhanced degeneration in the nuclei of cells, as evidenced by DAPI staining and increased the subG1 population, suggesting the induction of cell death. Together, these results suggest that fucoidan and alginate from the brown algae C. sinuosa are promising anticancer compounds, particularly when used in combination with vitamin C.

Extraction of Fucoidan from Turbinaria decurrens and the Synthesis of Fucoidan-Coated AgNPs for Anticoagulant Application.

Brown seaweeds usually contain alginate as a major polymer. The second major sulfated polymer in brown seaweeds is fucoidan, which has huge potential in medicinal applications. In this study, the photosynthetic pigments from Turbinaria decurrens were first extracted using chloroform/methanol in the ratio of 1:1 (v/v), followed by fucoidan extraction with yields of 5.58% (crude) and 1.28% (purified fucoidan) from the dry weight of seaweed, whereas alginate was extracted with a yield of 14.7% DW of seaweed. The isolated fucoidan possessing anticoagulation property was identified and characterized as (1–3)-α-l-fucopyranosyl residues with sulfate groups primarily at the C4 position and to a lesser extent at the C2 position, whereas in the case of galactose, at the C3 and C6 positions. The AgNPs synthesized using isolated fucoidan exhibit strong anticoagulant activity and possess a good antibacterial property against Gram-negative clinical bacteria. Functional groups such as O–H, C–H, and S=O associated with sugar residues in sulfated fucoidan are involved in the synthesis of the nanoparticles with a spherical shape, size ranging from 10 to 60 nm, and showing polydispersity. From this study, we conclude that fucoidan-coated anionic AgNPs synthesized from T. decurrens have tremendous potential in drug development.

Inhibition of SARS-CoV-2 Virus Entry by the Crude Polysaccharides of Seaweeds and Abalone Viscera In Vitro.

Much attention is being devoted to the potential of marine sulfated polysaccharides as antiviral agents in preventing COVID-19. In this study, sulfated fucoidan and crude polysaccharides, extracted from six seaweed species (Undaria pinnatifida sporophyll, Laminaria japonica, Hizikia fusiforme, Sargassum horneri, Codium fragile, Porphyra tenera) and Haliotis discus hannai (abalone viscera), were screened for their inhibitory activity against SARS-CoV-2 virus entry. Most of them showed significant antiviral activities at an IC50 of 12~289 μg/mL against SARS-CoV-2 pseudovirus in HEK293/ACE2, except for P. tenera (IC50 > 1000 μg/mL). The crude polysaccharide of S. horneri showed the strongest antiviral activity, with an IC50 of 12 μg/mL, to prevent COVID-19 entry, and abalone viscera and H. fusiforme could also inhibit SARS-CoV-2 infection with an IC50 of 33 μg/mL and 47 μg/mL, respectively. The common properties of these crude polysaccharides, which have strong antiviral activity, are high molecular weight (>800 kDa), high total carbohydrate (62.7~99.1%), high fucose content (37.3~66.2%), and highly branched polysaccharides. These results indicated that the crude polysaccharides from seaweeds and abalone viscera can effectively inhibit SARS-CoV-2 entry.

Brown seaweeds as a source of anti-hyaluronidase compounds

Hyaluronidase enzymes disrupt hyaluronic acid, causing angiogenesis, tumor invasiveness, metastasis, inflammation, and skin aging. Phlorotannin, alginate and fucoidan were extracted successively from the blade and stipe samples of two Sargassum seaweeds and Eisenia arborea thallus. These were evaluated for their in vitro anti-hyaluronidase and antioxidant activities (DPPH and reducing power assay). The crude phlorotannin content was highest in the blade of S. tenerrimum (22.405 ± 3.6 μg/mg), followed by S. vulgare blade (18.385 ± 3.29 μg/mg) with lower amounts in the stipe portion. The highest yield of alginate and fucoidans was obtained from the blade samples of S. vulgare (0.322 ± 0.38 and 0.198 ± 0.016%), followed by S. tenerrimum (0.090 ± 0.01 and 0.063 ± 0.005%) and E. arborea thallus (0.047 ± 0.008 and 0.032 ± 0.003%). The sulfate content was higher in fucoidan than alginate extracted from the stipe regions of the seaweeds. Phlorotannin, fucoidan and alginate from S. vulgare, S. tenerrimum, and E. arborea possessed anti-hyaluronidase activity as evident by a decrease in the N-acetylglucosamine release. The highest anti-hyaluronidase activity was achieved in the extract of S. tennerimum blade (37.67 ± 2.3% inhibition) due to its high phlorotannin content. Alginate and fucoidan extracted from the stipes of Sargassum species possess higher bioactivities than the blade samples. The FTIR study ascertained that alginate with a high guluronic acid and high sulfated fucoidan were extracted from the stipe samples compared to the blade samples. This increased viscosity and promoted bioactivity respectively. Further studies to evaluate the emulsifying and viscosity properties of these compounds are required before they can be considered for commercial applications.

Is the endogenous ligand for PEAR1 a proteoglycan: clues from the sea

Platelet Endothelial Aggregation Receptor 1 (PEAR1) is an orphan receptor of unknown function which mediates powerful activation of platelets and endothelial cells in response to crosslinking by antibodies and sulfated polysaccharides belonging to the dextran and fucoidan families. PEAR1 is a single transmembrane protein composed of 15 epidermal growth factor-like repeat sequences and with a conserved binding motif, YXXM, which when phosphorylated binds to phosphoinositide 3-kinase (PI3K). The 13th of the repeats has a heparin-binding sequence that is the site of interaction with the sulfated fucoidans and the only known endogenous ligand FcεRIα. Crosslinking of PEAR1 drives Src family kinase phosphorylation of the cytosolic tail leading to binding and activation of PI3K. In this Opinion Article, we summarize the literature on PEAR1 expression, structure and signaling, and the search for further endogenous ligands. We highlight one article in which phosphorylation of a 150 kDa platelet protein by heparin-containing ligands has been reported and propose that PEAR1 is a receptor for one or more glycosaminoglycan-conjugated proteins (proteoglycans). The up-regulation of PEAR1 at sites of inflammation in the vasculature and its role in angiogenesis suggests a role in the interplay of inflammation, platelets, coagulation, and thromboinflammation. We speculate that this may explain the link between single nucleotide variants in PEAR1 and cardiovascular disease.

In Vitro Anti-Coagulant Effects of Fucoidan Sulfate Grafted on TiO2 Nano-Film

The objective of this study was to examine anticoagulant effects of fucoidan sulfate grafted on a TiO₂ nano-film. Using silica sol as a film-forming binding agent and high-molecular-weight polyvinyl alcohol as a film-forming aid, a nano-TiO₂ film was produced by applying a bonding film-forming method. Photocatalytic performance and resistance to heat, corrosion, and aging were investigated. Using glutaraldehyde as a cross-linking agent, brown algal polysaccharide sulfate was grafted onto the surface of NH₃ plasma-treated nano-film. The effects of pH, reaction temperature, and reaction time on grafting effects of nano-film are discussed. XPS was used to analyze chemical elements on the surface of nano-film, and partial thromboplastin time (APTT), thromboplastin time (PT), and thrombin time (TT) were used to evaluate anticoagulant activity of the graft nano-film In Vitro. The TiO₂ nano-film showed excellent resistance to heat, water, corrosion, and aging, and produced good interfacial adhesion performance. The grafting process optimum occurred at pH 2, 40 °C, and a reaction time of 6 h. Under these conditions, the optimal value of grafted silk fibroin membrane APTT was 72 s, and coagulation time of APTT and TT was increased by 37 s and 6 s, respectively, compared with the control, suggesting anticoagulant effects. Regarding stability, grafted fucoidan sulfate did not dissolve easily from the matrix; therefore, this product appears to be a promising novel biomaterial with effective anticoagulant properties.

Functional Characterization of a New GH107 Endo-α-(1,4)-Fucoidanase from the Marine Bacterium Formosa haliotis.

Fucoidans from brown macroalgae are sulfated fucose-rich polysaccharides, that have several beneficial biological activities, including anti-inflammatory and anti-tumor effects. Controlled enzymatic depolymerization of the fucoidan backbone can help produce homogeneous, defined fucoidan products for structure-function research and pharmaceutical uses. However, only a few endo-fucoidanases have been described. This article reports the genome-based discovery, recombinant expression in Escherichia coli, stabilization, and functional characterization of a new bacterial endo-α-(1,4)-fucoidanase, Fhf1, from Formosa haliotis. Fhf1 catalyzes the cleavage of α-(1,4)-glycosidic linkages in fucoidans built of alternating α-(1,3)-/α-(1,4)-linked l-fucopyranosyl sulfated at C2. The native Fhf1 is 1120 amino acids long and belongs to glycoside hydrolase (GH) family 107. Deletion of the signal peptide and a 470 amino acid long C-terminal stretch led to the recombinant expression of a robust, minimized enzyme, Fhf1Δ470 (71 kDa). Fhf1Δ470 has optimal activity at pH 8, 37–40 °C, can tolerate up to 500 mM NaCl, and requires the presence of divalent cations, either Ca2+, Mn2+, Zn2+ or Ni2+, for maximal activity. This new enzyme has the potential to serve the need for controlled enzymatic fucoidan depolymerization to produce bioactive sulfated fucoidan oligomers.

Ion-exchange purification and structural characterization of five sulfated fucoidans from brown algae.

Fucoidans are a diverse class of sulfated polysaccharides integral to the cell wall of brown algae, and due to their various bioactivities, they are potential drugs. Standardized work with fucoidans is required for structure–function studies, but remains challenging since available fucoidan preparations are often contaminated with other algal compounds. Additionally, fucoidans are structurally diverse depending on species and season, urging the need for standardized purification protocols. Here, we use ion-exchange chromatography to purify different fucoidans and found a high structural diversity between fucoidans. Ion-exchange chromatography efficiently removes the polysaccharides alginate and laminarin and other contaminants such as proteins and phlorotannins across a broad range of fucoidans from major brown algal orders including Ectocarpales, Laminariales and Fucales. By monomer composition, linkage analysis and NMR characterization, we identified galacturonic acid, glucuronic acid and O-acetylation as new structural features of certain fucoidans and provided a novel structure of fucoidan from Durvillaea potatorum with α-1,3-linked fucose backbone and β-1,6 and β-1,3 galactose branches. This study emphasizes the use of standardized ion-exchange chromatography to obtain defined fucoidans for subsequent molecular studies.

Structural Characterization and α-Glucosidase Inhibitory and Antioxidant Activities of Fucoidans Extracted from Saccharina japonica.

Two sulfated fucoidan fractions (Lj3 and Lj5) were extracted from Saccharina japonica and then subjected to acid hydrolysis to obtain Lj3h and Lj5h. Lj3h and Lj5h were characterized using IR, methylation analysis, and mass spectrometry. It was found that Lj3h and Lj5h were homogeneous low molecular weight fucoidans. Specifically, Lj3h was composed of the main chain of 1,3-linked α-L-fucopyranose residues with sulfate at C-2 and/or C-4 and three different monosaccharides (galactose, glucose, mannose) branched at C-2 and/or C-4 of fucose residue. Lj5h contained backbones of alternating galactopyranose residues and fucopyranose residues attached via a 1→3 linkage (galactofucan) and 1→6 linked galactan. The sulfation pattern was mainly located at C2/C4 fucose or galactose residues and more branches occupied at C-4 of fucose residue and C-2, C-3 or/and C-6 of galactose residue. In vitro assay indicated that, among the four fucoidans tested, only Lj5 showed potent α-glucosidase inhibitory activity with IC50 of 153.27±22.89 μg/mL, and the two parent fucoidans, Lj3 and Lj5, showed better antioxidant activity than their derivatives. These findings highlight the structure and bioactivity diversity of Saccharina japonica-derived fucoidans.

Structural Characterization of Fucoidan from Laminaria hyperborea: Assessment of Coagulation and Inflammatory Properties and Their Structure-Function Relationship.

The structure of fucoidan isolated from Laminaria hyperborea was elucidated and chemically tailored in order to obtain a clear structure-function relationship on bioactive properties with a minimal amount of variations among the tested molecules. Analysis revealed a sugar composition of 97.8% fucose and 2.2% galactose. Analysis of the glycosidic linkages showed (1→3)-α-l-fuco-pyranose (31.9%) to be the dominant residue, followed by 1→2-linked (13.2%) and 1→4-linked (7.7%) fuco-pyranose as well as a high degree of branching (22.4%). Inductively coupled plasma mass spectrometry (ICP-MS) revealed a sulfate content of 53.8% (degree of sulfation (DS) = 1.7). Raman spectroscopy determined SO4 located axial at 4C and equatorial at 2C as well as an absence of acetylation. SEC-MALS analysis determined a high molecular weight (Mw = 469 kDa), suggesting a highly flexible main chain with short side chains. Both chemical shifts of the fucoidan, proton, and carbon were assigned by NMR and revealed a highly heterogeneous structure in terms of glycosidic linkages. Bioactivity was assessed using a lepirudin-based whole blood model. The immediate responses by coagulation and complement cascades were measured by prothrombine factor 1 and 2 (PTF1.2) and the terminal complement complex (TCC). Cytokines involved in inflammation were detected in a 27-plex cytokine assay. Fucoidan with a high Mw and DS inhibited coagulation, complement, and the cytokines PDGF-BB, RANTES, and IP-10, while activating MCP-1. These effects were obtained at the concentration of 1000 ug/mL and partly at 100 ug/mL. In low concentrations (10 ug/mL), a coagulation stimulating effect of highly sulfated fucoidans (DS = 1.7, Mw = 469 kDa or 20.3) was obtained. These data point to a multitude of effects linked to the sulfation degree that needs further mechanistic exploration.

Hypolipidemic effects of sulfated fucoidan from Kjellmaniella crassifolia through modulating the cholesterol and aliphatic metabolic pathways

Kjellmaniella crassifolia was cultured firstly in recent years in Dalian, China. To elucidate the hypolipidemic effects and functional mechanisms of fucoidan (KF) in K. crassifolia, hypolipidemic activities were studied using the established hyperlipemia Wistar rat model, corresponding chemical compositions and structures were analyzed. The results show that KF is 71.68% carbohydrate and 20.04% sulfate. The monosaccharides of KF mainly consist of fucose (31.89%) and galactose (23.54%), with sulfate bound at the equatorial C-4 position and at the axial C-2/3 position of fucpyranose. These findings show that an animal’s hyperlipidemia and antioxidative stress can be remarkably improved by KF and that the effects of KF are time- and dose-dependent. The molecular mechanism of KF modulates hyperlipidemia by inhibited cholesterol and aliphatic acid synthesis, accelerating the mitochondrial β-oxidation or peroxisomal oxidation degradation of aliphatic acid in vivo. These findings suggested that fucoidan extracted from K. crassifolia could be developed as a natural food used to treat hyperlipidemia.

Use of fluorescein isothiocyanate isomer I to study the mechanism of intestinal absorption of fucoidan sulfate in vivo and in vitro.

A new method to label fucoidan sulfate was established with tyramine and fluorescein isothiocyanate isomer I (FITC). Fluorescence spectrophotometry and high performance liquid chromatography verified the successful labelling of fucoidan by FITC. The results of the single-pass intestinal perfusion indicated that the jejunum and ileum are the main absorption sites, and there was carrier saturation. In addition, fucoidan sulfate at 1mg/ml had no inhibitory effect on Caco-2 cell proliferation. Studies on the transmembrane transport mechanism showed that fucoidan can be absorbed because the apparent permeability coefficient of the drugs (Papp ) A→B was 3.78+0.03 ×10-6 and that of B→A was 1.42+0.19 ×10-6 . The peak absorption of fucoidan occurred at 120min after administration; moreover, the higher the concentration used, the worse the absorption was, suggesting the saturation of transport carriers. The absorption was temperature dependent: the absorption at 37°C was much better than that at 4°C. Further, the absorption of fucoidan sulfate might rely on clathrin endocytosis as chlorpromazine (10μg/ml) significantly inhibited it.

Basic fibroblast growth factor released from fucoidan-modified chitosan/alginate scaffolds for promoting fibroblasts migration

Wound repair process is initiated immediately after injury by releasing a variety of growth factors. It is known that basic fibroblast growth factor (bFGF) promoted fibroblasts migration, proliferation and effective helped skin wound healing. However, the use of bFGF is limited by two drawbacks, which are its short half-life and easily degraded by enzymes. In this study, we fabricate fucoidan-modified chitosan/alginate (F-CS/Alg) scaffold to protect and control release bFGF to regulate fibroblast migration activity. The experimental results show that oversulfated fucoidan was successfully prepared, with 43% sulfation degree. The 43% sulfated fucoidan (F43) exhibited effective DPPH scavenging activity, good biocompatibility and protected bFGF from trypsin degradation. The F43-CS/Alg scaffold could maintain bFGF activity and control its release, reaching 2.52 ng/mL for 10 h releasing. In vitro cell studies demonstrate that F43-CS/Alg scaffold showed a considerable elevation in cell viability and promoted L929 fibroblasts migration efficiently. In brief, bFGF loaded F43-CS/Alg scaffold effectively accelerating fibroblast migration for wound repair and could have a great potential in clinical applications in the future.