Crude extracts of the marine sponge Geodia corticostylifera from Brazilian Coast have
previously shown antibacterial, antifungal, cytotoxic, haemolytic and neurotoxic activities.
The present work describes the isolation of the cyclic peptides geodiamolides A, B, H and I
(1–4) from G. corticostylifera and their anti-proliferative effects against sea urchin eggs and
human breast cancer cell lineages. Its structure–activity relationship is discussed as well. In
an initial series of experiments these peptides inhibited the first cleavage of sea urchin eggs …