Structural requirements for biological activity of the marine alkaloid ascididemin

Comparison of the biological activities observed for ascididemin (2) and synthetic precursors/analogs has established the importance of N-8 in ring A, and a completed ring E, to topoisomerase II enzyme inhibition, human tumor cytotoxicity and antifungal/antibacterial properties. The results also suggest the presence of multiple mechanisms of toxicity by 2 towards mammalian cell systems.