An antiplasmodial new (bis)indole alkaloid from the hard coral Tubastraea sp.

Tubastarea sp., a stony coral (Dendrophylliidae) from the Great Hanish in the Archipelago of the Hanish Islands, Yemen, contains, in addition to the known aplysinopsin (1) and 6-bromo-3'-deimino-3'-oxoaplysinopsin (2), the new bis(indole) alkaloid (3). The structures of compounds (1-3) were elucidated by interpretation of spectral data. Compound 3 inhibits the growth of Plasmodium falciparum (chloroquine-resistant strain) with an IC(50) 1.2 microg mL(-1).