Bioactive Compounds from Marine Extremophiles

With the development of the self-contained underwater breathing apparatus (SCUBA) and other recently developed marine collecting techniques, numerous bioactive secondary metabolites have been isolated and characterized from eubacteria, archaea, and fungi. These microorganisms have adopted strategies to grow in marine environments, which, for the purposes of this book, the authors define to be extreme environments. The classification of these extremophiles is challenging, as they typically inhabit environments high in salinity, with extreme temperatures as well as variable acidity and pressure. In addition, when these extremophiles are isolated, they are typically grown under mesophilic conditions in research laboratories. Herein, the authors discuss the isolation, bioactivity, and preclinical evaluation of bioactive natural products produced by both culturable and unculturable marine microorganisms, demonstrating that the marine world is an unexploited source of new chemical entities. Notably, there are seven FDA-approved marine-derived drugs, five of which are derived from mutualistic interactions between microorganisms and marine invertebrates. Based on their success in the clinics, there has been a major focus on natural product isolation from marine environments. As of January 2014, out of the 36 marine-derived agents in Phase I–III clinical trials, 31 are derived from microorganisms, demonstrating the ability of marine extremophiles to be inexhaustible sources of drug candidates. Furthermore, as ecological niches evolve, these extremophiles will also evolve and be unique sources of novel pharmacophores.