Fucoidans from the phaeophyta Scytosiphon lomentaria: Chemical analysis and antiviral activity of the galactofucan component.

The brown seaweed Scytosiphon lomentaria produces moderate amounts of fucoidans. By cetrimide fractionation, typical heavily sulfated galactofucans are obtained, with no major signs of chemical heterogeneity, together with fractions with higher proportions of xylose, mannose and uronic acids. Anyway, fucose is the most important monosaccharide in most of the subfractions of the subsequent extracts. The fucan moieties appear to be mostly as 3-linked α-l-fucopyranosyl units, with several patterns of sulfate and branching. Galactose is mostly 6-linked, whereas mannose appears to be 2-linked, and xylose appears mostly as terminal stubs. Small amounts of 2-O-acetylated fucose units appear. A high and selective antiviral activity against HSV-1 and HSV-2 was determined for the galactofucan fractions whereas the uronofucoidans were inactive.