Synthesis and Cytotoxic Activity of Novel Mono- and Bis-Indole Derivatives: Analogues of Marine Alkaloid Nortopsentin.

Background: The oceans cover more than 70% of the earth's surface, which represents over 95% of the biosphere. Therefore, oceans provide a wealth of marine invertebrates, especially sponges, ascidians, bryozoans and molluscs that produce structurally unique bioactive metabolites such as alkaloids. The bioactive scaffolds of marine alkaloids exhibit cytotoxic activities against human cancer cell lines.