title: The system of fucoidans from the brown seaweed Dictyota dichotoma: chemical analysis and antiviral activity.
abstract: Room-temperature acid (pH 2) extraction of Dictyota dichotoma thalli yielded 2.2% of sulfated polysaccharides. Further extraction with the same solvent at 70°C was conducted sequentially for nine times, with a total yield of 7.2%. Fucose was the main monosaccharide only in the room-temperature extract (EAR) and in the first 70°C extract (EAH1). The remaining fractions showed increasing amounts of mannose (the main neutral monosaccharide), xylose and uronic acids. Fractionation by means of cetrimide precipitation and redissolution in increasing sodium chloride solutions has allowed obtaining several subfractions from each extract. The fractions redissolved at lower NaCl concentrations have large amounts of uronic acids and lesser sulfate contents, whereas those redissolved at higher NaCl concentrations are heavily sulfated and have low uronic acid contents. For the fucose-rich extracts (EAR and EAH1), fractionation leads to uronoxylomannofucan-rich and galactofucan-rich fractions. The remaining extracts gave rise to complex mixtures, with mannose and uronic acid-rich polysaccharides. Moderate inhibitory effect against herpes virus (HSV-1) and Coxsackie virus (CVB3) were found for the galactofucan-rich fractions. Most of the other fractions were inactive against both viruses, although some xylomannan-rich fractions were also active against HSV-1.
authors.affiliation: Departamento de Química Orgánica-CIHIDECAR, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires, Argentina; Instituto de Biotecnología y Biología Molecular, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calle 49 y 115, 1900 La Plata, Argentina.
authors.forename: Melissa
authors.initials: M
authors.lastname: Rabanal
authors.forename: Nora M A
authors.initials: NM
authors.lastname: Ponce
authors.forename: Diego A
authors.initials: DA
authors.lastname: Navarro
authors.forename: Ricardo M
authors.initials: RM
authors.lastname: Gómez
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Stortz
mesh_terms: D000998:Antiviral Agents / Q000737:chemistry* / Q000494:pharmacology*; D004770:Enterovirus / Q000187:drug effects; D018259:Herpesvirus 1, Human / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D020128:Inhibitory Concentration 50; D000459:Phaeophyceae / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry* / Q000494:pharmacology*; D013696:Temperature
chemical_list: D000998:Antiviral Agents; D011134:Polysaccharides; C007789:fucoidan
keywords: Antiviral; Brown seaweeds; Dictyota dichotoma; Fucoidans; Galactofucans