Antiviral and Cytotoxic Activities of Polysaccharides Extracted from Four Tropical Seaweed Species

Polysaccharides extracted from Rhodymenia pseudopalmata, Solieria filiformis, Hydropuntia cornea (Rhodophyta) and Sargassum fluitans (Phaeophyceae) were evaluated for its cytotoxic and antiviral activities against Herpes simplex virus (HSV-Type 1). Chemical structures were characterized by FT-IR spectroscopy and C-13-NMR analyses. Polysaccharides from Sargassum fluitans (EC50 = 42.8 mu g/ml) and Solieria filiformis (EC50 = 136.0 mu g/ml) showed antiviral activity against herpes simplex virus type-I in vitro at a multiplicity of infection (MOI) of 0.01 ID50/cells without cytotoxicity (1-200 mu g/mL). The activity observed suggests that sulphation, molecular weight and carbohydrate nature of these polysaccharides may be involved in this activity. To better understand the antiviral activity of the polysaccharides evaluated, it seems important to study the mechanism of action involved. These polysaccharides could be studied further to evaluate their potential use as antiviral drugs.