Antitumor potential of natural products from Mediterranean ascidians

Ascidians, invertebrates belonging to the subphylum Urochordata (Tunicata), are renowned for their great chemical diversity, and during the last 25 years, they have been shown to produce an array of cytotoxic molecules. Among the first six marine-derived compounds that have reached clinical trials as antitumor agents, three are derived from ascidians, as evidence of the high potential of these organisms as a new source of antitumor compounds. Reported in this communication are some recent results on the chemistry of Mediterranean ascidians; a number of new molecules with different structural features but all endowed with antiproliferative or cytotoxic activity are discussed. These results strongly evidence the highly significant role that Mediterranean ascidians natural products could play in anticancer drug discovery and development process.