Biological activities of seaweed extracts from British Columbia, Canada, and Korea .1. Antiviral activity

We report the results of the first screening of 89 seaweeds collected from British Columbia, Canada, and Korea for antiviral activity. Various concentrations of methanol extracts of dried algae were tested against 100 plaque-forming units of herpes simplex virus type 1 and Sindbis virus in Vero cell monolayers. Eleven extracts inhibited both viruses, and 22 extracts were active against only one of the viruses. Thus, in total 37% of the species were active, and only two of these extracts also showed cytotoxicity at the concentrations tested. The antiviral activities were proportionately more frequent in the Korean extracts (56% compared with 27% of Canadian extracts), but in general the more potent extracts were of Canadian origin. Analipus japonicus was the most potent anti-herpes species, and the Korean species of Codium fragile was the most potent against both viruses. This high yield of antiviral extracts illustrates the potential of seaweeds as a resource for bioactive compounds.