Antitumor potential of natural products from marine ascidians of the Gibraltar Strait:: A survey

The chemical study of a selection of marine ascidians from the Gibraltar Strait has led to the characterization of a collection of natural products of diverse biosynthetic origin. The structures were elucidated by spectroscopic methods and, in certain instances, the absolute stereochemistry was determined using chiral auxiliaries following the Mosher method. In particular, the new compounds isolated from the ascidians Phallusia fumigata (Grube, 1864), Botryllus leachi (Savigny, 1816), Stolonica socialis (Hartmayer, 1903), and Pseudodistoma obscurum (Peres, 1959) are presented and key aspects of the structural elucidation are discussed. In order to anticipate a possible antitumor application, the cytotoxicity of the new compounds was evaluated against cell lines P-388 (suspension culture of a lymphoid neoplasm from a DBA/2 mouse), A-549 (monolayer culture of a human lung carcinoma), HT-29 (monolayer culture of a human colon carcinoma), and MEL-28 (monolayer culture of a human melanoma).