Sulfated Xylomannans from the Red Seaweed Sebdenia Polydactyla: Structural Features, Chemical Modification and Antiviral Activity

Abstract

Background: Many viruses display affinity for cell surface heparan sulfate proteoglycans with biological relevance in virus entry. This raises the possibility of the application of sulfated polysaccharides in antiviral therapy. Methods: In this study, we analysed polysaccharide fractions isolated from Sebdenia polydactyla. Results: The purified xylomannan sulfate and its further sulfated derivatives showed strong activity against herpes simplex virus type-1 (HSV-1). Their 50% inhibitory concentration values were in the range 0.35–2.8 µg/ml and they lacked cytotoxicity at concentrations up to 1,000 µg/ml. The major polysaccharide, which had 0.6 sulfate groups per monomer unit and an apparent molecular mass of 150 kDa, contained a backbone of α-(1→3)-linked D-mannopyranosyl residues substituted at position 6 with a single stub of ß-D-xylopyranosyl residues. Conclusions: The degree of sulfation seemed to play an important role because desulfation and/or further sulfation of the isolated macromolecules largely influenced their in vitro anti-HSV-1 activity.