Isolation of an anti-influenza virus substance, MC26 from a marine brown alga, Sargassum piluliferum and its antiviral activity against influenza virus

Summary We previously conducted the screening of anti-influenza virus activity from 338 species of marine algae collected in Japan coasts in order to develop new anti-influenza virus agents. In this study, we attempted to isolate and purify an anti-influenza virus substance from one of the brown algae species, Sargassum piluliferum which exhibited potent anti-influenza virus activity. An anti-influenza virus substance, MC26 was isolated 1.5 mg from the MeOH extract from 200 g wet weight of s. piluliferum by various chromatographies. MC26 showed potent anti-influenza virus activity with lower cytotoxicity as compared with known active compounds, Amantadine and MC24 we previously isolated as an anti-influenza virus substance from a marine brown alga, Turbinaria ornate. The selectivity index of MC26, which shows efficacy of antiviral agents, was higher than those of a conventional anti-influenza virus agent, Amantadine and MC24, anti-influenza virus agent from other marine alga. These results suggested that MC26 might be a new effective component with ant-influenza virus activity.