Polysaccharides from Sargassum tenerrimum: Structural features,chemical modification and anti-viral activity

Herpes simplex viruses (HSVs) display affinity for cell-surface heparan sulfate proteoglycans with biological relevance in virus entry. Here, we exploit an approach to inhibiting HSV infection by using a sulfated fucoidan, and a guluronic acid-rich alginate derived from Sargassum tenerrimum, mimicking the active domain of the entry receptor. These macromolecules have apparent molecular masses of 30 ± 5 and 26 ± 5 kDa, respectively. They and their chemically sulfated derivatives showed activity against herpes simplex virus type 1 (HSV-1). Their inhibitory concentration 50% (IC₅₀) values were in the range 0.5–15 μg/ml and they lacked cytotoxicity at concentrations up to 1000 μg/ml. The anti-HSV activity increased with increasing sulfate ester content. Our results suggest the feasibility of inhibiting HSV infection by blocking viral entry with polysaccharide having specific structure.