Novel sulfated xylogalactoarabinans from green seaweed Cladophora falklandica: Chemical structure and action on the fibrin network
Introduction
Cladophora Kützing is one of the largest green algal genera and has a worldwide distribution. Within the class Cladophorophyceae, the genus Cladophora is characterized by its simple thallus architecture: branched, uniseriate filaments of multinucleate cells. Cladophora cell walls, which are several micrometers thick, were reported to consist largely of cellulose, which represents about 15% of the biomass (Wissel, Mayr, & Lücke, 2008).
In spite of its wide distribution, which comprises mostly marine, but also fresh water environments, and of its abundance, there is only scarce information about the structure of the sulfated polysaccharides biosynthesized by algae of this genus. Percival and coworkers studied the structural features of the water soluble polysaccharides from Cladophora rupestris (Percival & McDowell, 1981). These studies established the presence of arabinose, galactose, xylose, rhamnose, and glucose in the approximate molar proportions of 3.7:2.8:1.0:0.4:0.2 (+8% protein) and 19.6% half ester sulfate. Application of degradative studies provided evidence of a highly branched structure, with xylose and galactose units at the ends of the branches and galactose, arabinose, and rhamnose residues occurring in the inner part of the molecules. Evidence of 6-linked and/or 6-sulfated galactofuranose units was obtained. Partial hydrolysis experiments led to the separation and characterization of the following fragments: l-arabinose 3-sulfate, d-galactose 6-sulfate, 3-linked and 6-linked d-galactobioses, 4- or 5-linked l-arabinobiose 3-sulfate, 4-linked d-xylobiose, a mixture of trisaccharides containing sulfated galactose and arabinose, and a mixture of pentasaccharides in which the molar ratio of arabinose to galactose was 4:1.
Later, the structural characteristics of the polysaccharides obtained from Cladophora socialis by extraction with dilute acid were reported (Sri Ramana & Venkata Rao, 1991). A molar ratio galactose:arabinose:xylose of 4.5:3.0:1.0 and 16.9% of sulfate were determined. Similar conclusions were obtained regards the arabinose units, but no galactose in the furanose form was detected. In this case, galactose units were found to be 3-linked and sulfated on C4 or C4 and C6.
Between the sulfated polysaccharides, sulfated fucans (SFs) and sulfated galactans (SGs) are currently the marine non-glycosaminoglycan (GAG) sulfated compounds most studied in glycomics. These polysaccharides exhibit therapeutic effects in several pathophysiological systems such as blood coagulation, thrombosis, neovascularization, cancer, inflammation, and microbial infections. As analogs of the largely employed GAGs and due to some limitations of the GAG-based therapies (Anand, Yusuf, Pogue, Ginsberg, & Hirsh, 2003; Kelton & Hirsh, 1980; Kelton & Warkentin, 2008), SFs and SGs comprise new carbohydrate-based therapeutics available for clinical studies. However, the degree and mechanism of action varies greatly, not only with the degree of sulfation, but also with their chemical structure, and other sulfated polysaccharides with different carbohydrate backbones and sulfate distributions have been investigated and were found to have similar properties (Ciancia, Quinitana, & Cerezo, 2010, Fernández et al., 2013).
In a previous paper, the effect in the fibrin network formation of sulfated galactans from green seaweeds of the order Bryopsidales was studied by measuring optical density (OD) at 405 nm vs time. It was shown that these galactans caused an impaired assembly of fibrin monomers into the fibrin polymer (Arata et al., 2015).
Kinetics of fibrin formation gives a different insight into the study of the coagulation process, contributing to the understanding of the mechanism of anticoagulant activity. On the other hand, the study of fibrinolysis is also crucial, because currently approved thrombolytic drugs have side effects, such as bleeding, low specificity on account of being indirect plasminogen activators, and high cost. The ‘holy grail’ for antithrombotic therapy, a drug that prevents coagulation without promoting bleeding, has yet to be found.
In this paper, structure of the major water-soluble sulfated polysaccharides from Cladophora falklandica was determined, and their anticoagulant effect was investigated, not only by general coagulation tests, but also through studies of their influence in fibrin formation and fibrinolysis. Besides, characteristics of the fibrin clot were examined using scanning electron microscopy.
Section snippets
Algal sample
Specimens of Cladophora falklandica (J.D. Hooker & Harvey) J.D. Hooker & Harvey were collected in Punta Este − Puerto Madryn − Chubut − Argentina (42°46′48″S, 64°57′W), in September 2010. The samples used in this work were in the vegetative state. Thalli of the seaweeds were washed with sea water and analyzed for epiphytic and epizoic contaminants in a Nikon AFX-II macroscope (Nikon, Japan). Voucher specimens were deposited in the Museum Bernandino Rivadavia, Buenos Aires Argentina (collection
Extraction and characterization of the sulfated polysaccharides
Water-soluble polysaccharides from green seaweed Cladophora falklandica were obtained by sequential extraction at room temperature and at 90 °C from the alcohol insoluble residue, giving a total yield of 29.2% of the dry milled material.
All the extracts have important amounts of carbohydrates and sulfate (Supplementary Table 1). Colorimetric assays indicated only trace amounts of uronic acids and no pyruvic acid ketals in these extracts, which have the same monosaccharides, but in different
Conclusions
The major water-soluble polysaccharides from Cladophora falklandica are sulfated xylogalactoarabinans. Their backbone is constituted by 4-linked pyranosic β-l-arabinose units. 3-Linked sulfated pyranosic arabinans were previously isolated from Codium species (Bryopsidales). On the other hand, pyranosic arabinose units were found to be part of arabinogalactans from green seaweeds Caulerpa racemosa (Bryopsidales) and Cladophora rupestris; however, their structure was not fully determined. In
Acknowledgement
This work was supported by a grant from the University of Buenos Aires, UBACYT 2014–2017, 20020130100576BA.
References (52)
- et al.
Chemical structure and anticoagulant activity of highly pyruvylated sulfated galactans from tropical green seaweeds of the order Bryopsidales
Carbohydrate Polymers
(2015) - et al.
Structure of a highly pyruvylated galactan sulfate from the pacific green alga Codium yezoense (Bryopsidales, Chlorophyta)
Carbohydrate Research
(2007) A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein dye binding
Analytical Biochemistry
(1976)- et al.
Sulfated xylomannans isolated from red seaweeds Chondrophycus papillosus and C. flagelliferus (Ceramiales) from Brazil
Carbohydrate Research
(2007) - et al.
Separation and quantitation of enantiomeric galactoses and their mono-O-methylethers as their diastereomeric acetylated 1-deoxy-1-(2-hydroxypropylamino) alditols
Carbohydrate Research
(1995) - et al.
Chemical structure and antiviral activity of the sulfated heterorhamnan isolated from the green seaweed Gayralia oxysperma
Carbohydrate Research
(2008) - et al.
Polysaccharides from Caulerpa racemosa. Purification and structural features
Carbohydrate Polymers
(2007) - et al.
Determination of the structures of cystocarpic carrageenans from Gigurtina skottsbergii by methylation analysis and NMR spectroscopy
Carbohydrate Research
(1993) - et al.
Polysaccharides from the green seaweeds Codium fragile and C. vermilara with controversial effects on hemostasis
International Journal of Biological Macromolecules
(2007) - et al.
A simple and rapid method for the permethylation of carbohydrates
Carbohydrate Research
(1984)
Dynamic changes of fibrin architecture during fibrin formation and intrinsic fibrinolysis of fibrin-rich clots
Journal of Biological Chemistry
A fungus-type β-galactofuranan in the cultivated Trebouxia photobiont of the lichen Ramalina gracilis
FEMS Microbiology Letters
(1 → 2) and (1 → 6)-linked β-d-galactofuranan of microalga Myrmecia biatorellae: Symbiotic partner of Lobaria linita
Carbohydrate Polymers
Rhamnogalactofuranan from the microalga Myrmecia biatorellae: Symbiotic partner of Lobaria linita
Phytochemistry
Anticoagulant activity of a unique sulphated pyranosic (1(3)-β-l-arabinan through direct interaction with thrombin
Journal of Biological Chemistry
Polysaccharides from the green seaweed Codium decorticatum: Structure and cell wall distribution
Carbohydrate Polymers
Measurement of uronic acids without interference from neutral sugars
Analytical Biochemistry
Heparin-induced thrombocytopenia: A historical perspective
Blood
Microdetermination of pyruvic and α-ketoglutaric acids
Archives of Biochemistry and Biophysics
Structural characterization of an anticoagulant-active sulfated polysaccharide isolated from green alga Monostroma latissimum
Carbohydrate Polymers
Protein measurements with the Folin phenol reagent
Journal of Biological Chemistry
Hydrolysis of plant cell walls with trifluoroacetic acid
Phytochemistry
Microwave-assisted desulfation of sulfated polysaccharides
Carbohydrate Polymers
A submicrodetermination of glucose
Journal of Biological Chemistry
Determination of native capsular polysaccharide structures of Streptococcus pneumoniae serotypes 39, 42, and 47F and comparison to genetically or serologically related strains
Carbohydrate Research
Structure of complex cell wall polysaccharides isolated from Trichoderma and Hypocrea species
Carbohydrate Research
Cited by (30)
Structure, anticoagulant and cytotoxic activity of a sulfated polysaccharide from green seaweed Chaetomorpha linum
2024, Natural Product ResearchLemon gum: Non-toxic arabinogalactan isolated from Citrus × latifolia with antiproliferative property against human prostate adenocarcinoma cells
2023, International Journal of Biological MacromoleculesTwo different morphotypes of freshwater Cladophora surera (Cladophorales, Chlorophyta) produce similar sulfated cell wall polysaccharides
2023, Algal ResearchCitation Excerpt :The sulfated polysaccharides from Cladophora socialis obtained by extraction with dilute acid [11] showed similar structural features, even though this species is known to be distantly related from the bona fide Cladophora clade containing the type species of the genus [2]. More recently, studies carried out by Arata et al. (2016) [12] on the sulfated polysaccharides from the seaweed Cladophora falklandica showed that they are xylogalactoarabinans constituted by a backbone of 4-linked β-l-arabinopyranose units, partially sulfated on C-3, and also on C-2. Besides, partial glycosylation mostly on C-2 with single stubs of β-d-xylopyranose, and/or β-d-galactofuranose or short chains comprising (1 → 5)- and/or (1 → 6)- β-d-galactofuranose linkages, was also found.
- 1
Research Member of the National Research Council of Argentina (CONICET).