2.3.2.3 Anticancer
Molecules with anticancer properties comprise the majority of bioactive molecules derived from marine sources. However, relatively few compounds enter pre-clinical and clinical trials and only a small group stems from microbes. Although chemically synthesised, ara-C (cytarabine) was designed based on the nucleosides from spongothymidine and spongouridine, originally isolated from the marine sponge, Tethya crypta, and is in clinical use for more than 40 years. Today, Yondelis®, a potent anticancer drug developed by Pharmamar from compounds produced by the tunicate Ecteinascidia tur-binata, is probably the most successful example of how marine natural products can lead to anticancer treat-ments.