[en] This Doctoral Thesis describes the extraction and fractionation of different marine invertebrates to obtain metabolites that show cytotoxic activity. For a structural determination of the effects of metabolites, different forms of use of various spectroscopic techniques and mass spectrometry are applied. In addition, cytotoxic activities of the metabolites were evaluated. Chapter 2: From the study of the sponge Cribrochalina sp. was isolated pembamide (1), a highly N-methylated peptide compound. It showed moderate cytotoxic activity against tumor cells. Chapter 3: A new member of the family of njaoaminas called njaoamine I (2) was isolated from the chemical study of the sponge Reniera sp. It showed moderate cytotoxic activity against tumor cells. Chapter 4: The chemical study of soft coral Protodendron repens was reported for the first time, resulting in the isolation of two xenicals, called protoxenicin A (3) and B (4), and whose structural novelty is the presence of a long chain of fatty acid. Chapter 5: Two new cyclic hexapeptides from the ascidia Lissoclinum bistratum, bistratamides M (5) and N (6). They are characterized by having in theis structures oxazole and thiazole rings. These cyclic peptides show moderate cytotoxic activity against human tumor cell lines. In addition, was performed the study of the interaction of Zn2+ with bistratamide K (7) that gave rise to the formation of a mononuclear Zn2+ complex of 7. Chapter 6: Daedophamida (8), a new cyclodepsipeptide, was isolated from the sponge Daedalopelta sp. Daedophamide showed significant cytotoxic activity against human tumor cell lines.

[gl] Esta Tese Doctoral describe a extracción e fraccionamiento de diferentes invertebrados mariños co fin de obter metabolitos que mostren actividade citotóxica. Para a determinación estructural de devanditos metabolitos aplicáronse distintas estratexias así como o uso de distintas técnicas espectroscópicas e de espectrometría de masas. Ademais, se evaluaron as actividades citotóxicas dos metabolitos illados. Capítulo 2: Do estudo da esponja Cribrochalina sp. illouse pembamida (1), un composto peptídico altamente N-metilado de orixe mariña, mostrando actividade citotóxica moderada fronte a células tumorales. Capítulo 3: Un novo integrante da familia das njaoamines que se denominou njaoamine I (2) illouse do estudo químico da esponxa Reniera sp. Mostrou unha actividade citotóxica moderada fronte a células tumorales. Capítulo 4: Reportouse por primeira vez o estudo químico do coral brando Protodendron repens que deu como resultado o illamento de dous xenicanos, chamados protoxenicina A (3) e B (4) e, que cuxa novidade estructural é a presenza dunha cadea longa de ácidos grasos. Capítulo 5: Illáronse dous novos hexapéptidos cíclicos da ascidia Lissoclinum bistratum, bistratamidas M (5) e N (6). Caracterízanse por posuír nas súas estruturas aneis de oxazol e tiazol. Estes péptidos cíclicos mostran unha actividade citotóxica moderada contra catro liñas celulares tumorales humanas. Ademais, realizouse o estudo da interacción do ion Zn2+ con bistratamida K (7) que deu lugar á formación dun complexo de Zn2+ mononuclear de 7. Capítulo 6: Daedophamida (8), un novo ciclodepsipéptido, illouse da esponxa Daedalopelta sp. Daedophamide mostrou actividade citotóxica significativa contra catro liñas celulares tumorales humanas.