Several clinically useful antitumor agents are now recognized to form complexes with one or more metals and to interact with DNA as their metal chelate(s). Further, for most of these agents, DNA interaction (i.e., binding/cleavage) is believed to represent the biochemical locus at which the therapeutic effect is mediated. The objective of this project is the identification of novel natural products that mediate DNA strand scission. Of special interest are agents that do so in a mechanistically novel fashion.