Resumen del Libro
Marine ecosystems have a very large amount of resources, most of them are still partially unknown, and few have been exploited for development of new industrial and toxicological products. The objective of this investigation was to determine if ascidia Rhopalaea sp. from the Pacific coast of Costa Rica had these chemical defenses against the bacteria Staphylococcus aureus and fungi Geotrichum candidum, and if so, to determine their main secondary metabolites in the extract. Ascidian was collected from the zone of Cuajiniquil, Guanacaste, between December 2007 and March 2008. Activity evaluation against the Gram positive bacteria and fungi was performed on ethanolic (95%) and acetonic extracts. Both extracts showed activity against Geotrichum candidum but only the acetonic extract showed activity against Staphylococcus aureus. A coumarin and one hydroxyanthraquinone were isolated from a crude extract of Rhopalaea sp. as metabolites present in the active fraction. The purification and isolation were performed by chromatographic techniques and solid phase extraction. Structural information was obtained by spectroscopy analyses: Ultraviolet (UV-Visible), Fourier Transform Infrared (FT-IR), Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS), Gas Chromatography Mass Spectrometry (GC/MS), Nuclear Magnetic Resonance of Proton (1H-NMR), and Carbon-13 (13C-NMR). Further studies are necessary for a characterization of their active components of this extract and a possible elucidation of the mechanisms of action.