ANTIHERPETIC ACTIVITY OF S1, AN ALGAL DERIVED SULFATED GALACTAN

The sulphated galactan S1 isolated from the red seaweed Pterocladia ca pillacea proved to be a selective antiviral compound against herpes si mplex virus types 1 and 2 (HSV-1 and HSV-2), human cytomegalovirus and pseudorabies virus. No cytotoxicity was observed with S1 at concentra tions about 500 mu g/mL that were in excess of the IC50 values (range from 3.2 to 12.0 mu g/mL for the different herpesviruses assayed). The antiherpetic action of S1 was independent of the host cell and the an tiviral assay. The kinetics of infectious virus adsorption to the host cell was highly inhibited in the presence of S1 whereas the subsequen t stage of virus penetration was not affected, The binding of radiolab elled HSV-1 particles was inhibited in a dose dependent manner confirm ing that the mode of action of S1 could be attributable to an inhibiti on of initial virus attachment to the host cell.