Antiviral activity of a sulphated polysaccharide from the red seaweed nothogenia fastigiata

Abstract The antiviral activity of polysaccharide fractions obtained from water extracts of the red seaweed Nothogenia fastigiata was investigated. Fraction F6, corresponding to a sulphated xylomannan, was found to inhibit efficiently the replication of herpes simplex virus type 1 (HSV-1). Furthermore, F6 selectively inhibited the replication of several other enveloped viruses including herpes simplex virus type 2, human cytomegalovirus (HCMV), respiratory syncytial virus, influenza A and B virus, Junin and Tacaribe virus and simian immunodeficiency virus. F6 was only weakly active against human immunodeficiency virus type 1 and 2. The mode of action of F6 against HSV-1 and HCMV could be ascribed to an inhibitory effect on virus adsorption.