Molluscicidal Metabolites from an Assemblage of Palmyra Atoll Cyanobacteria

Molluscicides can play an important role in the control of schistosomiasis because snails of the genus Biomphalaria act as intermediate hosts for the parasite. Schistosomiasis is one of 13 neglected tropical diseases with high morbidity and mortality that collectively affect one billion of the world's poorest population, mainly in developing countries. Thiopalmyrone (1) and palmyrrolinone (2), metabolites isolated from extracts of a Palmyra Atoll environmental assemblage of two cyanobacteria, cf. Oscillatoria and Hormoscilla spp., represent new and potent molluscicidal chemotypes against Biomphalaria glabrata (LC50 = 8.3 and 6.0 mu M, respectively). A slight enhancement in molluscicidal effect (LC50 = 5.0 mu M) was observed when these two natural products were utilized as an equimolar binary mixture.