Dragmacidin G, a Bioactive Bis-Indole Alkaloid from a Deep-Water Sponge of the Genus Spongosorites

Abstract

A deep-water sponge of the genus <i>Spongosorites</i> has yielded a bis-indole alkaloid which we have named dragmacidin G. Dragmacidin G was first reported by us in the patent literature and has recently been reported by Hitora et al. from a sponge of the genus <i>Lipastrotheya</i>. Dragmacidin G is the first in this series of compounds to have a pyrazine ring linking the two indole rings. It also has a rare <i>N</i>-(2-mercaptoethyl)-guanidine side chain. Dragmacidin G shows a broad spectrum of biological activity including inhibition of methicillin-resistant <i>Staphylococcus aureus</i>, <i>Mycobacterium tuberculosis</i>, <i>Plasmodium falciparum,</i> and a panel of pancreatic cancer cell lines.