title: Heterofucans from Dictyota menstrualis have anticoagulant activity.
abstract: Fucan is a term used to denote a family of sulfated L-fucose-rich polysaccharides which are present in the extracellular matrix of brown seaweed and in the egg jelly coat of sea urchins. Plant fucans have several biological activities, including anticoagulant and antithrombotic, related to the structural and chemical composition of polysaccharides. We have extracted sulfated polysaccharides from the brown seaweed Dictyota menstrualis by proteolytic digestion, followed by separation into 5 fractions by sequential acetone precipitation. Gel electrophoresis using 0.05 M 1,3-diaminopropane-acetate buffer, pH 9.0, stained with 0.1% toluidine blue, showed the presence of sulfated polysaccharides in all fractions. The chemical analyses demonstrated that all fractions are composed mainly of fucose, xylose, galactose, uronic acid, and sulfate. The anticoagulant activity of these heterofucans was determined by activated partial thromboplastin time (APTT) using citrate normal human plasma. Only the fucans F1.0v and F1.5v showed anticoagulant activity. To prolong the coagulation time to double the baseline value in the APTT, the required concentration of fucan F1.0v (20  g/ml) was only 4.88-fold higher than that of the low molecular weight heparin Clexane  (4.1  g/ml), whereas 80  g/ml fucan 1.5 was needed to obtain the same effect. For both fucans this effect was abolished by desulfation. These polymers are composed of fucose, xylose, uronic acid, galactose, and sulfate at molar ratios of 1.0:0.8:0.7:0.8:0.4 and 1.0:0.3:0.4:1.5:1.3, respectively. This is the fist report indicating the presence of a heterofucan with higher anticoagulant activity from brown seaweed.
authors.affiliation: Laboratório de Biotecnologia de Polímeros Naturais, Departamento de Bioquímica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil.
authors.forename: I R L
authors.initials: IR
authors.lastname: Albuquerque
authors.forename: K C S
authors.initials: KC
authors.lastname: Queiroz
authors.forename: L G
authors.initials: LG
authors.lastname: Alves
authors.forename: E A
authors.initials: EA
authors.lastname: Santos
authors.forename: E L
authors.initials: EL
authors.lastname: Leite
authors.forename: H A O
authors.initials: HA
authors.lastname: Rocha
mesh_terms: D000925:Anticoagulants / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002849:Chromatography, Gas; D004587:Electrophoresis, Agar Gel; D006801:Humans; D008970:Molecular Weight; D010314:Partial Thromboplastin Time; D000459:Phaeophyceae / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D011517:Prothrombin Time; D012624:Seaweed / Q000737:chemistry*
chemical_list: D000925:Anticoagulants; D011134:Polysaccharides; C007789:fucoidan