Structure and anticoagulant activity of a highly ramified sulfated arabinan from the green seaweed Cladophora falklandica

MARINA CIANCIA; PAULA X. ARATA; MARÍA PAULA RAFFO; ANA MARÍA LAURICELLA; IRENE QUINTANA

Moscú

Simposio; 18th European Carbohydrate Symposium; 2015

Zelinsky Institut of Organic Chemistry

STRUCTURE AND ANTICOAGULANT ACTIVITY OF A HIGHLY RAMIFIED SULFATED ARABINAN FROM GREEN SEAWEED CLADOPHORA FALKLANDICAMarina Cianciaa,b, Paula X. Arataa, María P. Raffoc, Ana M. Lauricellad, Irene QuintanadaCátedra de Química de Biomoléculas, Departamento de Biología Aplicada y Alimentos, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, 1417 Buenos Aires, Argentina. bCIHIDECAR-CONICET, Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina. cCentro Nacional Patagónico-CONICET, Bvd. Brown 2915, U9120ACD Puerto Madryn, Chubut, Argentina. dLaboratorio de Hemostasia y Trombosis, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria - Pabellón 2, C1428EHA Buenos Aires, Argentina. E-mail: ciancia@agro.uba.arSulfated polysaccharides from Cladophora falklandica were extracted 3 times with water at room temperature and at 90ºC. Chemical analysis showed similar results for all the extracts. The structure of a major fraction obtained by ion exchange chromatography from the second room temperature water extract (CX2F1) was studied in detail by chemical and spectroscopic methods. It comprises a backbone of 4-linked -L-arabinopyranose units with sulfate groups or single stubs of -D-xylose linked to C-2. Sulfate groups and terminal units or small chains of -galactofuranose units are linked to C-3. These side chains comprise 5- and also 6-linked galactofuranose units, the latter, in lesser amounts. Although galactose in the furanose form was detected previously in C. rupestris by Percival and coworkers1 and these units were suggested to be present in other seaweed extracts, the structure of the corresponding polysaccharides was not elucidated. However polysaccharides comprising -D-galactofuranose units are well documented as part of other organisms, as fungi2 and bacteria3. Anticoagulant activity of CX2F1 was studied by general coagulation assays. For a 100 µg.mL-1 final solution of the polysaccharide in plasma, APTT ratio (sample vs control), was 3.2 ± 0.1 and TT ratio was 2.9 ± 0.1. When purified fibrinogen was used instead of plasma, TT like-assay ratio was 2.5 ± 0.2, suggesting that the anticoagulant activity could arise, at least partially, from direct thrombin inhibition. In order to determine the effect on the fibrin network, formation, structure and lysability of plasma fibrin clots were also studied, showing significant changes in kinetic parameters. Quantitative analysis of the photographs obtained by SEM, showed that the structure of fibrin network in the presence of CX2F1 was more opened, with increased fiber length (2.1 ± 0.8 µm vs. 1.4 ± 0.7 µm), but lesser number of fibers per field (31.9 ± 8.0 vs. 60.5± 6.0) when compared with control network. CX2F1 reduced the final time of lysis and increased the lysis rate. In all assays significant differences (p