INVESTIGADORES
PONCE Nora Marta Andrea
artículos
Título:
Fucoidans from the brown seaweed Adenocystis utricularis; extraction methods, antiviral activity and structural studies
Autor/es:
PONCE, NORA M. A.; PUJOL, CARLOS A.; DAMONTE, ELSA B.; FLORES MARIA L.; STORTZ CARLOS A.
Revista:
CARBOHYDRATE RESEARCH
Editorial:
Elsevier
Referencias:
Lugar: Amsterdam; Año: 2003 vol. 338 p. 153 - 165
ISSN:
0008-6215
Resumen:
The brown seaweed Adenocystis utricularis (family Adenocystaceae, order Ectocarpales sensu lato) was extracted in parallel withthree solvents usually utilized for obtaining fucoidans: distilled water, 2% calcium chloride solution and diluted hydrochloric acid(pH 2) solution. In each case, the extraction was effected at room temperature and then at 70 °C. The extraction yields andcharacteristics of the products were similar in the three cases, with only minor differences. The analytical features of the productsindicate that two different types of fucoidans are present in this seaweed. One of them, mostly extracted at room temperature, iscomposed mainly of L-fucose, D-galactose and ester sulfate (the ‘galactofucan’). The other product (the ‘uronofucoidan’) is themajor component of the extracts obtained at 70 °C. It is composed mainly of fucose, accompanied by other monosaccharides(mostly Man, but also Glc, Xyl, Rha and Gal), significant amounts of uronic acids and low proportions of sulfate ester.Fractionation with the cationic detergent cetrimide has allowed achieving a better separation of the galactofucan and uronofucoidan components. The galactofucans show a high inhibitory activity against herpes simplex virus 1 and 2, with no cytotoxicity,whereas the uronofucoidans carry no antiviral activity. Structural studies on the galactofucan fractions were carried out bymethylation analysis, desulfation and NMR spectroscopy. The fucan constituent is mainly composed of 3-linked a-L-fucopyranosyl backbone, mostly sulfated at C-4, and branched at C-2 with non-sulfated fucofuranosyl and fucopyranosyl units, and2-sulfated fucopyranosyl units. The galactan moiety is more heterogeneous, with predominant D-galactopyranose units linked onC-3 and C-6, and sulfation mostly on C-4, even in terminal non-reducing units. It may be inferred that at least some of thesegalactose units carry the B-configuration.