Marine Bi-, Bis-, and Trisindole Alkaloids

This chapter, covering the chemistry literature up until June 2013 and comprising 142 references, records the chemical structures of 130 bi-, bis-, and trisindole alkaloids isolated from a plethora of marine phyla including bacteria, algae, bryozoans, sponges, mollusks, hard corals, and ascidians. While the vast majority of bisindoles have been isolated from marine sponges, biindoles are more commonly found in red algae species than sponges. Trisindoles are far less common than bisindoles in the marine environment and have been limited to two species of sponge and a single species of marine microbe. Antimicrobial activity and cytotoxicity dominate the bioactivities explored for selected members of this family of alkaloids. Synthetic approaches to 28 natural products are presented in 33 schemes, and in the absence of any in vivo biosynthetic studies, the putative biosyntheses of eight bisindole metabolites are presented.