Abstract
Various active anticancer agents are derived from plants and terrestrial microorganisms. Isolation of C-nucleosides from the Caribbean sponge, Cryptotheca crypta, four decades ago, provided the basis for the synthesis of cytarabine, the first marine derived anticancer agent to be developed for clinical use. Cytarabine is currently used in the routine treatment of patients with leukaemia and lymphoma. Gemcitabine, one of its fluorinated derivatives, has also been approved for use in patients with pancreatic, breast, bladder, and non-small-cell lung cancer. Over the past decade, several new experimental anticancer agents derived from marine sources have entered preclinical and clinical trials. Present study address anticancer drug discovery from an evolutionary perspective and present a series of case studies that demonstrate that the rate of anticancer drug discovery can be increased greatly by targeted screening of natural compounds from marine sources.