A study of fucoidan from the brown seaweed Chorda filum

Immunomodulatory activity of fucoidan against aspirin-induced gastric mucosal damage in rats

Gastric ulcers and related complications associated with the use of non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin, represent a major global health problem. In the present study, we investigate the immunological activity of fucoidan against aspirin-induced gastric mucosal damage in rats. Thirty-six rats were randomly divided into the following, normal (Carboxy methyl cellulose 0.05 %), aspirin (Asp-400mg/kg) treated, fucoidan alone (Fu-0.02 g/kg, daily for 14 days) and Fu+Asp. Cytokines, total nitrite and nitrate (NOx) analysis and tissue localization of Cyclooxygenase 1, 2 and epidermal growth factor receptor (EGFR) were done using Elisa and immunohistochemistry respectively. Histopathology of gastric tissue, collagen deposition was performed using Hematoxylin and Eosin and Masson's trichrome were performed. Treatment of rats with a single dose of aspirin (400mg/kg, orally) led to significant alterations in the levels of total nitrite and nitrate (NOx), interleukins (IL-4, 6, 10, 12), tumor necrosis factor (TNF-α), and interferon gamma (IFN-γ). Notably, collagen deposition in glandular tissue and localization of cyclooxygenase 1, 2, and epidermal growth factor were considerably affected in aspirin-treated rats. These severities were prevented to a significant extent in rats pretreated with fucoidan (0.02 g/kg/day for two weeks orally). Our findings collectively indicate that the gastro-protective effect of fucoidan against aspirin-induced ulceration in rats is mediated through its immunomodulatory properties.

Attenuation of N-nitrosodiethylamine-induced liver fibrosis by high-molecular-weight fucoidan derived from Cladosiphon okamuranus

BACKGROUND AND AIM

Liver fibrosis is closely associated with the progression of various chronic liver diseases. Fucoidan exhibits different biological properties such as anti-inflammatory, anti-oxidant and anti-fibrotic activities. The aim of this study was to determine whether oral fucoidan administration inhibits N-nitrosodiethylamine (DEN)-induced liver fibrosis.

METHODS

Liver fibrosis was induced in rats by injecting DEN (50 mg/kg). Rats were given 2% of crude fucoidan solution or 2% of high-molecular-weight (HMW) fucoidan solution. They were divided into a crude fucoidan group, an HMW fucoidan group, a DEN alone group, a DEN + crude fucoidan group, a DEN + HMW fucoidan group and a control group.

RESULTS

Liver fibrosis and hepatic hydroxyproline levels were significantly more decreased in the DEN + HMW fucoidan group than in the DEN-alone group. Anti-fibrogenesis was unremarkable in the DEN + crude fucoidan group. Hepatic messenger RNA levels and immunohistochemistry of transforming growth factor beta 1 were markedly increased by DEN. This increase was attenuated by HMW fucoidan. Hepatic chemokine ligand 12 expression was increased by DEN. This increase was suppressed by HMW fucoidan. HMW fucoidan significantly decreased the DEN-induced malondialdehyde levels. Also, fucoidan markedly increased metallothionein expression in the liver. Fucoidan was clearly observed in the liver by immunohistochemical staining in HMW fucoidan-treated rats, while it was faintly stained in the livers of crude fucoidan-treated rats.

CONCLUSION

These findings suggest that the HMW fucoidan treatment causes anti-fibrogenesis in DEN-induced liver cirrhosis through the downregulation of transforming growth factor beta 1 and chemokine ligand 12 expressions, and that scavenging lipid peroxidation is well-incorporated in the liver.

Further studies on the composition and structure of a fucoidan preparation from the brown alga Saccharina latissima

The polysaccharide composition of a fucoidan preparation isolated from the brown alga Saccharina latissima (formerly Laminaria saccharina) was reinvestigated. The preparation was fractionated by anion-exchange chromatography, and the fractions obtained were analyzed by chemical methods combined with NMR spectroscopy. Several 2D procedures, including HSQC, HMQC-TOCSY, and HMQC-NOESY, were used to obtain reliable structural information from the complex spectra, and the signal assignments were additionally confirmed by comparison with the literature spectra of the related polysaccharides and synthetic oligosaccharides. In accordance with the previous data, the main polysaccharide component was shown to be a fucan sulfate containing a backbone of 3-linked alpha-l-fucopyranose residues sulfated at C-4 and/or at C-2 and branched at C-2 by single sulfated alpha-l-fucopyranose residues. In addition, three other types of sulfated polysaccharide molecules were detected in the total fucoidan preparation: (i) a fucogalactan having a backbone of 6-linked beta-d-galactopyranose residues branched mainly at C-4 and containing both terminal galactose and fucose residues; (ii) a fucoglucuronomannan having a backbone of alternating 4-linked beta-d-glucopyranosyluronic acid and 2-linked alpha-d-mannopyranose residues with alpha-l-fucopyranose residues as single branches at C-3 of alpha-d-Manp; and (iii) a fucoglucuronan having a backbone of 3-linked beta-d-glucopyranosyluronic acid residues with alpha-l-fucopyranose residues as single branches at C-4. Hence, even a single algal species may contain, at least in minor amounts, several sulfated polysaccharides differing in molecular structure. Partial resolution of these polysaccharides has been accomplished, but unambiguous evidence on their presence as separate entities was not obtained.

Structural studies on a novel fucogalactan sulfate extracted from the brown seaweed Laminaria japonica

A low molecular weight fucogalactan, obtained from the brown seaweed Laminaria japonica, was separated into three fractions (LF1, LF2 and LF3) by DEAE-Sepharose FF column chromatography. All three fractions contained predominantly fucose, sulfate group and galactose. The results showed that the main fraction LF2 consisted of l-fucose, d-galactose and sulfate at a molar ratio 6:1:9. Structural study on the LF2 was carried out by NMR spectroscopy. The backbone of LF2 was primarily (1-->3)-linked alpha-l-fucopyranose residues (75%) and a few (1-->4)-alpha-l-fucopyranose linkages (25%). The branch points were at C-4 of 3-linked alpha-l-fucopyranose residues by beta-d-galactopyranose unites (35%, molar ratio) or at C-2 of 3-linked alpha-l-fucopyranose residues by non-reducing terminal fucose unites (65%, molar ratio). Sulfate groups occupied at position C-4 or C-2, sometimes C-2, 4 to fucose residues, and C-3 and/or C-4 to galactose residues. The structure of LF2 was supposed as following: .

Fucoidan, a sulfated polysaccharide, inhibits adipogenesis through the mitogen-activated protein kinase pathway in 3T3-L1 preadipocytes

AIMS

Fucoidan, consisting of L-fucose together with xylose, galactose and mannose, is a sulfated polysaccharide from brown seaweeds, which has been reported to affect the development of adipocytes. However, the role of fucoidan in adipogenesis remains elusive. In the present study, we have investigated the inhibitory effects of fucoidan on adipocyte differentiation via mitogen-activated protein kinase (MAPK) signaling pathway in 3T3-L1 preadipocytes.

MAIN METHODS

Differentiation of 3T3-L1 preadipocytes was induced in the presence or absence of fucoidan. The effects of fucoidan on adipogenic gene expression and MAPK activation were investigated.

KEY FINDINGS

Fucoidan treatment inhibits adipocyte differentiation, evidenced by decreased lipid accumulation and down regulation of adipocyte markers. Fucoidan then inhibited the expression of both early CCAAT-enhancer-binding proteins alpha (C/EBPalpha) and peroxisome proliferator-activated receptors gamma (PPARgamma) and late activating protein 2 (aP2) adipogenic transcription factors, which is a crucial role for adipocyte development. Moreover, our results revealed that fucoidan inhibited the early activation of p38 MAPKs, extracellular signal-regulated kinases (ERK) and Jun N-terminal kinase (JNK).

SIGNIFICANCE

Overall, these findings are a strong indication that fucoidan might inhibit adipogenesis in 3T3-L1 preadipocytes, due to inhibition of the MAPK signaling pathway that involves adipogenic transcription factors.

Fucoidan increases TNF-alpha-induced MMP-9 secretion in monocytic cell line U937

OBJECTIVE

To investigate the effect of fucoidan on the expression of matrix metalloproteinase-9 (MMP-9) from monocytes.

METHODS

Human monocytic cell line U937 was purchased from ATCC. During the experiment, FBS-free 1640 was used and U937 was cultivated with 20 ng/ml TNF-alpha and/or different concentrations of fucoidan for 24 h. RT-PCR experiments were used to determine the MMP-9 mRNA expression. ELISA and gelatin zymography detected MMP-9 amounts and activity in the supernatant. The intracellular level of MMP-9 was assayed by Western blot, and the level of CD44 on the surface was assayed by FACS.

RESULTS

In this study, we showed that pro-inflammatory cytokine TNF-alpha up-regulated U937 MMP-9 mRNA and protein levels (P < 0.05). Fucoidan can increase the TNF-alpha-induced MMP-9 secretion from U937 (P < 0.05), but no significant difference was observed in MMP-9 mRNA. The intracellular level of MMP-9 treated with TNF-alpha and fucoidan was lower (P < 0.05) than that treated with TNF-alpha alone. In addition, we demonstrated that fucoidan downregulated the surface level of CD44, the main molecule to which MMP-9 attaches.

CONCLUSIONS

We demonstrated that fucoidan post-translationally regulated MMP-9 secretion from U937. Reduced intracellular level and decreased membrane attachment may contribute to the increase in MMP-9 secretion.

Characteristics and nutritional and cardiovascular-health properties of seaweeds

While marine algae have traditionally formed part of the Oriental diet, their major use in Western countries has been in the phytocolloid industry. Only a few coastal communities outside Asia have customarily used seaweeds as components of special dishes. Of late, however, seaweeds have gained importance as foodstuffs in Western countries and most recently as components of functional foods because of their high dietary fiber, mineral, vitamin, and phytochemical content, low energy levels, and high concentrations of certain polyunsaturated fatty acids. The present paper reviews the available data for some of the components of the major edible algae and studies several factors that can affect their physiochemical properties (e.g., hydration, water and oil-holding capacity, fermentability, binding capacity, etc.) and, in turn, their nutritional importance. The effects of marine alga consumption on growth and body weight, mineral availability, lipid metabolism, blood pressure, and antioxidant properties are reviewed, together with preliminary data on the effects of some functional foods containing seaweeds on lipid metabolism and gene expression of enzymes engaged in antioxidant protection. This review concludes with some remarks regarding the danger of the improper use of seaweeds in herbal medications. In addition, as the properties of algae are highly dependent on their individual composition, any generalization regarding these properties may be considered misleading and scientifically inappropriate.

Structural analysis of a fucoidan from the brown alga Fucus evanescens by MALDI-TOF and tandem ESI mass spectrometry

A fucoidan, a heterogeneous sulfated polysaccharide from the brown alga Fucus evanescens, was depolymerized under solvolytic conditions, and its ethanol-extracted low-molecular-weight fraction was analyzed by MALDI-TOFMS and ESIMS/MS. It was found that the mixture contained unsulfated oligosaccharides including some monosulfated components, which were shown to consist of mainly (1-->3)-linked 2-O-sulfonated fucose residues (from 1 to 4). Minor components of the mixture were shown to contain 2-O- and 4-O-sulfonated xylose and galactose residues. Among them, mixed monosulfonated fucooligosaccharides were detected and characterized: Xyl-(1-->4)-Fuc, Gal-(1-->4)-Fuc, Gal-(1-->4)-Gal-(1-->4)-Fuc, Gal-(1-->4)-Gal. Fucose, galactose, and xylose residues were shown to be mainly 2-O-sulfonated with traces of 4-O-sulfonation. Glucuronic acid was also found as a part of non-sulfated fucooligosaccharides: Fuc-(1-->3)-GlcA, Fuc-(1-->4)-Fuc-(1-->3)-GlcA, Fuc-(1-->3)-Fuc-(1-->4)-Fuc-(1-->3)-GlcA.

Quantification and localization of fucoidan in Laminaria japonica using a novel antibody

The establishment of a simple technique to determine the concentration of fucoidan was developed by using a monoclonal antibody against fucoidan. This antibody reacted with fucoidans purified from Laminaria japonica Areschoug (Makombu in Japanese) and Kjellmaniella gyrate Miyabe (Gagome), but not with polysaccharides from Undaria pinnatifida Suringar (Wakame). Neither laminarin nor algenic acid, which are constituents in Laminaria japonica, were recognized by the prepared antibody. Application of the enzymed-linked immunosorbent assay (ELISA) inhibition assay increased the specificity of fucoidan in measuring the fucoidan contents. On the basis of these results, it was ascertained that the ELISA inhibition assay of using the anti-fucoidan monoclonal antibody was rapid, accurate, and sensitive in measuring the content of fucoidan. In addition, the localization of fucoidan in Laminaria japonica was investigated. This is the first report of fucoidan being restricted to the outer cortical layer.

Structure, biology, evolution, and medical importance of sulfated fucans and galactans

Sulfated fucans and galactans are strongly anionic polysaccharides found in marine organisms. Their structures vary among species, but their major features are conserved among phyla. Sulfated fucans are found in marine brown algae and echinoderms, whereas sulfated galactans occur in red and green algae, marine angiosperms, tunicates (ascidians), and sea urchins. Polysaccharides with 3-linked, beta-galactose units are highly conserved in some taxonomic groups of marine organisms and show a strong tendency toward 4-sulfation in algae and marine angiosperms, and 2-sulfation in invertebrates. Marine algae mainly express sulfated polysaccharides with complex, heterogeneous structures, whereas marine invertebrates synthesize sulfated fucans and sulfated galactans with regular repetitive structures. These polysaccharides are structural components of the extracellular matrix. Sulfated fucans and galactans are involved in sea urchin fertilization acting as species-specific inducers of the sperm acrosome reaction. Because of this function the structural evolution of sulfated fucans could be a component in the speciation process. The algal and invertebrate polysaccharides are also potent anticoagulant agents of mammalian blood and represent a potential source of compounds for antithrombotic therapies.

Effects of molecular weight and hydrolysis conditions on anticancer activity of fucoidans from sporophyll of Undaria pinnatifida

Hydrolyzed fucoidans, from sporophyll of Undaria pinnatifida, were used to determine the effects of molecular weight (Mw) and hydrolysis conditions on cancer cell growth. Native fucoidans showed anticancer activity of 37.6%. When hydrolyzed in boiling water with HCl for 5 min, fucoidans (Mw = 490 kDa) significantly increased anticancer activity to 75.9%. However, fucoidans hydrolyzed in a microwave oven showed little improvement of anticancer activity and even exhibited the inhibition activity below 30% when treated more than 90s. This suggests that anticancer activity of fucoidans could be significantly enhanced by lowering their Mw only when they are depolymerized by mild condition.

Dietary fiber and antioxidant capacity in Fucus vesiculosus products

Several nutraceutical products have been developed from Fucus vesiculosus, a brown edible seaweed, rich in dietary fiber and polyphenolic antioxidants (phlorotannins). The aim of this work was to compare the antioxidant capacity and polysaccharide composition of raw Fucus with those of some common commercial nutraceuticals. All tested products contained a high percentage of dietary fiber (45-59%), raw Fucus powder being the sample with the highest content. Also, raw Fucus powder exhibited significantly higher antioxidant capacity (determined by FRAP, ABTS and ORAC assays) than the commercial fucoidans and commercial antioxidant extracts. Polyphenols (phlorotannins) seem to be the main contributors to Fucus' antioxidant capacity in both raw powder and commercial fucoidans.

A sulfated glucuronofucan containing both fucofuranose and fucopyranose residues from the brown alga Chordaria flagelliformis

A fucoidan fraction composed of l-fucose, sulfate, and d-glucuronic acid in a molar proportion of about 1:1:0.25 and small amount of acetyl groups was isolated from the brown alga Chordaria flagelliformis. Several modified polysaccharides were prepared from the native fucoidan using solvolytic desulfation, carboxyl reduction, and partial acid hydrolysis. Polysaccharide structures were elucidated by methylation analysis and 1D and 2D NMR spectroscopy. The fucoidan was shown to contain a backbone of 3-linked alpha-l-fucopyranose residues, about one-third of which are glycosylated at C-2 by alpha-d-glucopyranosyluronic acid residues. About half of the latter residues are glycosylated at C-4 by single alpha-L-fucofuranose residues or by disaccharides alpha-L-Fucf-(1-->2)-alpha-L-Fucf-(1-->. Fucofuranose residues are mono- and disulfated at different positions, whereas some additional sulfate groups occupy C-2 and C-4 of the backbone, the latter position being also partially acetylated.

Structural Analysis of Fucoidans

Sulfated polysaccharides of brown algae (“fucoidans”) constitute a wide variety of biopolymers from simple sulfated fucans up to complex heteropolysaccharides composed of several neutral monosaccharides, uronic acid and sulfate. The increased interest in this class of polysaccharides is explained by their high and versatile biological activities, and hence, by their possible use in new drug design. Structural analysis of several fucoidans demonstrates that their biological properties are determined not only by charge density, but also by fine chemical structure, although distinct correlations between structure and biological activity cannot be formulated at present. The aim of this review is to describe the methods of structural analysis currently used in fucoidan chemistry, and to discuss some new information on the structures of fucoidans presented in recent publications.

Inhibition of thrombin and factor Xa by Fucus evanescens fucoidan and its modified analogs

Specimens of fucoidan extracted from Fucus evanescens were purified from protein and polyphenols, deacetylated and depolymerized by fucoidanase for evaluation of their biological activity. Deacetylation did not modify the capacity of fucoidan to inhibit thrombin and factor Xa, while purification from protein and polyphenols reduced this capacity. Depolymerization of fucoidan increased its capacity to inhibit thrombin mainly through heparin cofactor II. All the studied specimens formed complexes with protamine sulfate.

Fucoidan: structure and bioactivity

Fucoidan refers to a type of polysaccharide which contains substantial percentages of L-fucose and sulfate ester groups, mainly derived from brown seaweed. For the past decade fucoidan has been extensively studied due to its numerous interesting biological activities. Recently the search for new drugs has raised interest in fucoidans. In the past few years, several fucoidans' structures have been solved, and many aspects of their biological activity have been elucidated. This review summarizes the research progress on the structure and bioactivity of fucoidan and the relationships between structure and bioactivity.

Structure, biological activity, and enzymatic transformation of fucoidans from the brown seaweeds

Recent advances in the study of fucoidans, biologically active sulfated alpha-L-fucans of diverse structures and synthesized exclusively by marine organisms, are overviewed. Their structure, biological activity, the products of their enzymatic degradation and the different enzymes of degradation and modification are considered.

Inhibitory effects of fucoidan on activation of epidermal growth factor receptor and cell transformation in JB6 Cl41 cells

Algal fucoidan is a marine sulfated polysaccharide with a wide variety of biological activities including anti-thrombotic, anti-inflammatory, and anti-tumor activities. In this study, we tested the hypothesis that fucoidan may suppress neoplastic cell transformation by inhibiting the phosphorylation of epidermal growth factor receptor (EGFR) in mouse epidermal JB6 Cl41 cells. Our results provided the first evidence that fucoidan from Laminaria guryanovae exerted a potent inhibitory effect on EGF-induced phosphorylation of EGFR. Consistent with its inhibitory action on phosphorylation of EGFR, fucoidan clearly suppressed the phosphorylation of extracellular signal-regulated kinase or c-jun N-terminal kinases induced by EGF. Moreover, EGF-induced the c-fos and c-jun transcriptional activities were inhibited by fucoidan, resulting to suppressing of activator protein-1 (AP-1) activity and cell transformation induced by EGF. Taken together, these results indicate that fucoidan might exert chemopreventive effects through the inhibition of phosphorylation of the EGFR.

Characterization of a fucoidan from Lessonia vadosa (Phaeophyta) and its anticoagulant and elicitor properties

Blades of Lessonia vadosa (Phaeophyta) were extracted with 2% CaCl(2) solution, affording in 4.4% yield a polysaccharide which contained fucose and sulfate groups in the molar ratio 1.0:1.12. The high negative optical activity value ([alpha](D)(22)=-134.0 degrees ), FT-IR and NMR analysis suggest the presence of a fucoidan. (13)C NMR spectrum of the polysaccharide obtained by solvolytic desulfation of native fucoidan indicated the major presence of 1-->3 linked alpha-l-fucan. Depolymerization of the native fucoidan with H(2)O(2) in the presence of copper(II) acetate gave in 54.8% yield a fraction with 33.7% of sulfate content. The native fucoidan (MW 320,000) showed good anticoagulant activity whereas the radical depolymerized fraction (MW 32,000) presented a weak anticoagulant activity. These polysaccharides showed significant activation of phenylalanine-ammonia lyase (PAL), lipooxygenase (LOX) and glutathione-S-transferase (GST) defence enzyme activities in tobacco plants.

Effect of sulphated polysaccharides on erythrocyte changes due to oxidative and nitrosative stress in experimental hyperoxaluria

Kidney stones are known to haunt humanity for centuries and increase in oxalate is a predominant risk factor for stone formation. The present study was initiated with a notion to study the oxidative and nitrosative stress on erythrocytes under oxalate stress and the putative role of sulphated polysaccharides. Hyperoxaluria was induced in two groups by the administration of 0.75% ethylene glycol in drinking water for 28 days and one of them was treated with sulphated polysaccharides from Fucus vesiculosus from the 8th day to the end of the experimental period of 28 days at a dose of 5 mg/kg body weight subcutaneously. Control and drug control (sulphated polysaccharides alone) were also included in the study. Glycolic and glyoxylic acid levels of urine were analyzed as an index of hyperoxaluria. The plasma enzymic markers of cellular integrity, redox status of red blood cells, osmotic fragility, and (14)C-oxalate binding were investigated. Urine and plasma nitric oxide metabolites, expression of inducible nitric oxide synthase protein, and mRNA were assessed in kidney to evaluate the nitrosative stress. Increased levels of glycolic and glyoxylic acid in urine indicated the prevalence of hyperoxaluria in ethylene glycol-administered groups. Plasma aspartate and alanine transaminase were not altered, but alkaline phosphatase and lactate dehydrogenase of hyperoxaluric group were increased indicating tissue damage. Activities of antioxidant enzymes were decreased, whereas erythrocyte membrane lipid peroxidation was increased in hyperoxaluric rats. Moreover, an altered fragility with an increase in oxalate binding activity was observed in hyperoxaluric group. Increase in nitric oxide metabolites levels in urine and plasma along with an increase in expression of inducible nitric oxide synthase protein and mRNA in kidney were observed in hyperoxaluric rats. Administration of sulphated polysaccharides to hyperoxaluric rats averted the abnormal increase in urinary glycolic and glyoxylic acid levels and enzyme activities, decreased lipid peroxidation, and increased the activities of antioxidant enzymes. Furthermore, increased nitrosative stress accompanying hyperoxaluria was also normalized on sulphated polysaccharides treatment. To conclude, sulphated polysaccharide administration was able to maintain the integrity of erythrocyte membrane and decrease the damage to erythrocytes in hyperoxaluria.

Sulphated polysaccharides: new insight in the prevention of cyclosporine A-induced glomerular injury

The scope of the current study was to examine the possible effects of sulphated polysaccharides against cyclosporine A-induced glomerular injury. Nephrotoxicity induced by cyclosporine A continues to be a major problem despite its potent immunosuppressive action. Adult male albino rats of Wistar strain were categorized into four groups. Two groups (II and IV) were administered cyclosporine A (25 mg/kg body weight, orally) for 21 days, in which Group IV rats were also treated simultaneously with sulphated polysaccharides (5 mg/kg body weight, subcutaneously) for the same period. A significant loss in body weight was noted in the cyclosporine A-induced rats. Renal damage was assessed in terms of decreased creatinine clearance and increased activity of lysosomal enzymes. The levels of glycoproteins were found to be decreased in the renal tissue, and a noticeable rise in glycosaminoglycanuria coupled with marked proteinuria was more prominent in the cyclosporine A-induced animals. Furthermore, the extent of kidney damage was assessed by histopathological findings. Toxic manifestations were also confirmed by transmission electron microscopic studies. These morphological abnormalities and other alterations in the renal tissue were significantly offset by sulphated polysaccharides supplementation. These findings underline that restoration of normal cells accredits sulphated polysaccharides, from Sargassum wightii, with nephroprotective role, against cyclosporine A-induced renal injury.

Electrospray ionization mass spectrometry of oligosaccharides derived from fucoidan of Ascophyllum nodosum

Algal fucoidan is a complex sulfated polysaccharide whose structural characterization requires powerful spectroscopic methodologies. While most of the structural investigations reported so far have been performed using NMR as the main spectroscopic method, we report herein data obtained by negative electrospray ionization mass spectrometry. MS analysis has been carried out on oligosaccharides obtained by partial hydrolysis of fucoidan from the brown algae Ascophyllum nodosum. Oligosaccharide mixtures were fractionated by size exclusion chromatography, which allowed the analysis of oligomers ranging from monosaccharide to pentasaccharide. Monosaccharides were detected as monosulfated as well as disulfated forms. Besides, part of the oligosaccharides exhibited a high content of sulfate, evidencing that fucoidan contains disulfated fucosyl units. Fragmentation experiments yielded characteristic fragment ions indicating that the fucose units are mainly 2-O-sulfated. This study demonstrates that highly sulfated oligosaccharides from fucoidan can be analyzed by ESIMS which gives additional information about the structure of this highly complex polysaccharide.

Polysaccharide and lipid composition of the brown seaweed Laminaria gurjanovae

Polysaccharide and lipid composition of the Pacific brown seaweed Laminaria gurjanovae is determined. Alginic acid is shown to be the main polysaccharide of its biomass (about 28%); it consists of mannuronic and guluronic acid residues at a ratio of 3 : 1. The yield of water-soluble polymannuronic acid is low and does not exceed 1.1% of dry biomass. High laminaran content (about 22%) is found, whereas the yield of fucoidan is no more than 3.6%. Laminaran consists of two fractions, soluble and insoluble in cold water, their ratio is 2.5 : 1. Practically, insoluble laminaran is a linear 1,3-beta-D-glucan, and the soluble fraction was shown to be 1,3;1,6- 3-D-glucan. The oligosaccharide products of desulfation or partial acidic hydrolysis of fucoidan were studied by MALDI TOF MS; they were found to be fuco- and galactooligosaccharides. The fucoidan is suggested to be a highly sulfated partially acetylated galactofucan (Fuc/Gal is -1 : 1). The main lipid components of the dried L. gurjanovae are neutral lipids and glyceroglycolipids, whereas phospholipids are found in minor amounts. The main fatty acid components of lipids are 14 : 0, 16 : 0, 16 : 1 n-7, 18 : 1 n-7, and 18 : 2 n-6 acids.

[Polysaccharides of algae: 60. Fucoidan from the Pacific brown alga Analipus japonicus (Harv.) Winne (Ectocarpales, Scytosiphonaceae)]

A fucoidan containing L-fucose, sulfate, and O-acetyl groups at a molar ratio of 3 : 2 : 1, as well as minor amounts of xylose, galactose, and uronic acids was isolated from the brown alga Analipus japonicus collected in the Sea of Japan. The structures of the native polysaccharide and the products of its desulfation and deacetylation were studied by the methods of methylation, periodate oxidation, and NMR spectroscopy. It was shown that the polysaccharide molecule mainly consists of a linear carbohydrate chain of (1-->3)-linked alpha-L-fucopyranose residues, which bear numerous branches in the form of single alpha-L-fucopyranose residues (three branches at position 4 and one branch at position 2 per each ten residues of the main chain). Sulfate groups occupy positions 2 and (to a lesser extent) 4, most of the terminal nonreducing fucose residues being sulfated twice. The acetyl groups are located predominantly at positions 4. The structural role of minor monosaccharides was not established.

Structural features and antiviral activity of sulphated fucans from the brown seaweed Cystoseira indica

Natural compounds offer interesting pharmacological perspectives for antiviral drug development. In this study, we have analysed sulphated-fucan-containing fractions isolated from the brown seaweed Cystoseira indica. The crude water extract (CiWE) and the main fraction (CiF3) obtained by anion exchange chromatography had potent antiviral activity against herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) without cytotoxicity for Vero cell cultures. Furthermore, they had no direct inactivating effect on virions in a virucidal assay, and lacked anticoagulant activity. The mode of action of these compounds could be mainly ascribed to an inhibitory effect on virus adsorption. Chemical, chromatographic and spectroscopic methods showed that the major polysaccharide had an apparent molecular mass of 35 kDa and contained a backbone of alpha-(1 --> 3)-linked fucopyranosyl residues substituted at C-2 with fucopyranosyl and xylopyranosyl residues. This sulphated fucan, considered the active principle of the C. indica water extract, also contained variously linked xylose and galactose units and glucuronic acid residues. Sulphate groups, if present, are located mostly at C-4 of (1 --> 3)-linked fucopyranosyl units, and appeared to be very important for the anti-herpetic activity of this polymer.

Renal peroxidative changes mediated by oxalate: The protective role of fucoidan

Oxalate, one of the major constituents of renal stones is known to induce free radicals which damage the renal membrane. Damaged epithelia might act as nidi for stone formation aggravating calcium oxalate precipitation during hyperoxaluria. In the present study, the beneficial effects of fucoidan on oxalate-induced free radical injury were investigated. Male Wistar rats were divided into four groups. Hyperoxaluria was induced in two groups by administration of 0.75% ethylene glycol in drinking water for 28 days and one of them was treated with fucoidan from Fucus vesiculosus at a dose of 5 mg/kg b.wt subcutaneously commencing from the 8th day of induction. A control and drug control (fucoidan alone) was also included in the study. The extent of renal injury in hyperoxaluria was evident from the increased activities of alkaline phosphatase, gamma-glutamyl transferase, beta-glucuronidase, N-acetyl-beta-D-glucosaminidase in urine. There was a positive correlation between plasma malondialdehyde levels and renal membrane damage indicating a striking relation between free radical formation and cellular injury. Increased protein carbonyl and decreased thiols further exemplified the oxidative milieu prevailing during hyperoxaluria. Decreased renal membrane ATPases accentuated the renal membrane damage induced by oxalate. Renal microscopic analysis showed abnormal findings in histology as an evidence of oxalate damage. The above biochemical and histopathological discrepancies were abrogated with fucoidan administration, indicating its protective role in oxalate mediated peroxidative injury.

Polysaccharide biological response modifiers

Biological response modifiers (BRMs) are substances which augment immune response. BRMs can be cytokines which are produced endogenously in our body by immune cells or derivatives of bacteria, fungi, brown algae, Aloe vera and photosynthetic plants. Such exogeneous derivatives (exogeneous BRMs) can be nucleic acid (CpG), lipid (lipotechoic acid), protein or polysaccharide in nature. The receptors for these exogeneous BRMs are pattern recognition receptors. The binding of exogeneous BRMs to pattern recognition receptors triggers immune response. Exogenous BRMs have been reported to have anti-viral, anti-bacterial, anti-fungal, anti-parasitic, and anti-tumor activities. Among different exogeneous BRMs, polysaccharide BRMs have the widest occurrence in nature. Some polysaccharide BRMs have been tested for their therapeutic properties in human clinical trials. An overview of current understandings of polysaccharide BRMs is summarized in this review.

Structure of a fucoidan from the brown seaweed Fucus serratus L

A fucoidan consisting of L-fucose, sulfate and acetate in a molar proportion of 1:1:0.1 and small amounts of xylose and galactose were isolated from the brown seaweed Fucus serratus L. The fucoidan structure was investigated by 1D and 2D 1H and 13C NMR spectroscopy of its desulfated and de-O-acetylated derivatives as well as by methylation analysis of the native and desulfated polysaccharides. A branched structure was suggested for the fucoidan with a backbone of alternating 3- and 4-linked alpha-L-fucopyranose residues, -->3)-alpha-L-Fucp-(1-->4)-alpha-L-Fucp-(1-->, about half of the 3-linked residues being substituted at C-4 by trifucoside units alpha-L-Fucp-(1-->4)-alpha-L-Fucp-(1-->3)-alpha-L-Fucp-(1-->. Minor chains built up of 4-linked alpha-fucopyranose and beta-xylose residues were also detected, but their location, as well as the position of galactose residues, remained unknown. Sulfate groups were shown to occupy mainly C-2 and sometimes C-4, although 3,4-diglycosylated and some terminal fucose residues may be nonsulfated. Acetate was found to occupy C-4 of 3-linked Fuc and C-3 of 4-linked Fuc in a ratio of about 7:3.

Structural and hemostatic activities of a sulfated galactofucan from the brown alga Spatoglossum schroederi. An ideal antithrombotic agent?

The brown alga Spatoglossum schroederi contains three fractions of sulfated polysaccharides. One of them was purified by acetone fractionation, ion exchange, and molecular sieving chromatography. It has a molecular size of 21.5 kDa and contains fucose, xylose, galactose, and sulfate in a molar ratio of 1.0:0.5:2.0:2.0 and contains trace amounts of glucuronic acid. Chemical analyses, methylation studies, and NMR spectroscopy showed that the polysaccharide has a unique structure, composed of a central core formed mainly by 4-linked beta-galactose units, partially sulfated at the 3-O position. Approximately 25% of these units contain branches of oligosaccharides (mostly tetrasaccharides) composed of 3-sulfated, 4-linked alpha-fucose and one or two nonsulfated, 4-linked beta-xylose units at the reducing and nonreducing end, respectively. This sulfated galactofucan showed no anticoagulant activity on several "in vitro" assays. Nevertheless, it had a potent antithrombotic activity on an animal model of experimental venous thrombosis. This effect is time-dependent, reaching the maximum 8 h after its administration compared with the more transient action of heparin. The effect was not observed with the desulfated molecule. Furthermore, the sulfated galactofucan was 2-fold more potent than heparin in stimulating the synthesis of an antithrombotic heparan sulfate by endothelial cells. Again, this action was also abolished by desulfation of the polysaccharide. Because this sulfated galactofucan has no anticoagulant activity but strongly stimulates the synthesis of heparan sulfate by endothelial cells, we suggested that this last effect may be related to the "in vivo" antithrombotic activity of this polysaccharide. In this case the highly sulfated heparan sulfate produced by the endothelial cells is in fact the antithrombotic agent. Our results suggested that this sulfated galactofucan may have a potential application as an antithrombotic drug.

Effect of enzyme preparation from the marine mollusk Littorina kurila on fucoidan from the brown alga Fucus distichus

A fucoidanase preparation from the marine mollusk Littorina kurila cleaved some glycosidic bonds in fucoidan from the brown alga Fucus distichus, but neither fucose nor lower oligosaccharides were produced. The main product isolated from the incubation mixture was a polysaccharide built up of disaccharide repeating units -->3)-alpha-L-Fucp-(2,4-di-SO3(-))-(1-->4)-alpha-L-Fucp-(2SO3(-))-(1-->, the structure coinciding with the idealized formula proposed for the initial substance. A polymer fraction with the same carbohydrate chain but sulfated only at positions 2 and nonstoichiometrically acetylated at positions 3 and 4 of fucose residues was isolated as a minor component. It is suggested that the native polysaccharide should contain small amounts of non-sulfated and non-acetylated fucose residues, and only their glycosidic bonds are cleaved by the enzyme. The enzymatic hydrolysis showed that irregular regions of the native polysaccharide containing acetylated and partially sulfated repeating units were assembled in blocks.

Partial characterization and anticoagulant activity of a heterofucan from the brown seaweed Padina gymnospora

The brown algae Padina gymnospora contain different fucans. Powdered algae were submitted to proteolysis with the proteolytic enzyme maxataze. The first extract of the algae was constituted of polysaccharides contaminated with lipids, phenols, etc. Fractionation of the fucans with increasing concentrations of acetone produced fractions with different proportions of fucose, xylose, uronic acid, galactose, and sulfate. One of the fractions, precipitated with 50% acetone (v/v), contained an 18-kDa heterofucan (PF1), which was further purified by gel-permeation chromatography on Sephadex G-75 using 0.2 M acetic acid as eluent and characterized by agarose gel electrophoresis in 0.05 M 1,3 diaminopropane/acetate buffer at pH 9.0, methylation and nuclear magnetic resonance spectroscopy. Structural analysis indicates that this fucan has a central core consisting mainly of 3-beta-D-glucuronic acid 1-> or 4-beta-D-glucuronic acid 1 ->, substituted at C-2 with alpha-L-fucose or beta-D-xylose. Sulfate groups were only detected at C-3 of 4-alpha-L-fucose 1-> units. The anticoagulant activity of the PF1 (only 2.5-fold lesser than low molecular weight heparin) estimated by activated partial thromboplastin time was completely abolished upon desulfation by solvolysis in dimethyl sulfoxide, indicating that 3-O-sulfation at C-3 of 4-alpha-L-fucose 1-> units is responsible for the anticoagulant activity of the polymer.

Isolation and partial characterization of fucan sulfates from the body wall of sea cucumber Stichopus japonicus and their ability to inhibit osteoclastogenesis

Two types of fucan sulfate were isolated from chloroform/methanol extract of the body wall of the sea cucumber Stichopus japonicus. One type (type A) contained 3.41 mmol fucose/g and 2.35 mmol sulfate/g, and the molecular mass was determined to be 9 kDa by gel permeation chromatography (GPC). Structural analysis suggested that type A consists of a backbone of (1-->3)-linked fucosyl residues that are substituted at C-4 with fucosyl residues, and that fucosyl residues are sulfated at C-2 and/or C-4. Another type (type B) contained 3.90 mmol fucose/g and 3.07 mmol sulfate/g, and the molecular mass was determined to be 32kDa by GPC. Structural analysis showed that type B is largely composed of unbranched (1-->3)-linked fucosyl residues, and that sulfate substitution(s) occur at C-2 and/or C-4. The potential of both types to inhibit osteoclastogenesis was examined by an in vitro assay system, showing that both types of fucan sulfate inhibit osteoclastogenesis more than 95% at 50 microg/mL concentration. These results suggest that types A and B fucan sulfate from sea cucumber are potent inhibitors of osteoclastogenesis.

Isolation and characterization of a fucoidan-degrading marine bacterial strain and its fucoidanase

A marine bacterial strain that degraded fucoidan from Kjellmaniella crassifolia (class Phaeophyceae, order Laminariales, family Laminariaceae) was isolated in our laboratory. The strain was gram-negative, ubiquinone 8 was the predominant respiratory quinone, and the GC-content of its genomic DNA was 36%. The cells of the strain were rod-shaped (2.0 microm long x 1.0 microm wide), and each cell was motile by means of one polar flagellum. Phylogenetic analysis of its 16S ribosomal DNA sequence indicated that it was a member of the family Alteromonadaceae. It produced a type of extracellular fucoidanase, an endosulfated fucan-digesting enzyme. The enzyme was purified with 3500-fold purity at 12.0% yield. Optimum conditions for the enzyme reaction were approximately pH 6.5 to 8.0 and temperature 30 degrees to 35 degrees C. The enzyme was activated by calcium ions, and maximum activity was observed in the presence of greater than 30 mM calcium ion.

A highly regular fraction of a fucoidan from the brown seaweed Fucus distichus L

A fucoidan fraction consisting of L-fucose, sulfate, and acetate in a molar proportion of 1:1.21:0.08 was isolated from the brown seaweed Fucus distichus collected from the Barents Sea. The 13C NMR spectrum of the fraction was typical of regular polysaccharides containing disaccharide repeating units. According to 1D and 2D 1H and 13C NMR spectra, the fucoidan molecules are built up of alternating 3-linked alpha-L-fucopyranose 2,4-disulfate and 4-linked alpha-L-fucopyranose 2-sulfate residues: -->3)-alpha-L-Fucp-(2,4-di-SO3-)-(1-->4)-alpha-L-Fucp-(2SO3-)-(1-->. The regular structure may be only slightly masked by random acetylation and undersulfation of several disaccharide repeating units.