Sesquiterpenoid metabolites with antiplasmodial activity from a Caribbean gorgonian coral, Eunicea sp

A chemical investigation of the Caribbean gorgonian octocoral Eunicea sp. collected along the northwest coast of Puerto Rico has afforded seven new secondary metabolites, 1-7, belonging to several types of sesquiterpenes, including elemane, eudesmane, and germacrane types, along with the known steroidal glycoside 8. Some of the new metabolites, 4-7, carry an unusual ester side chain at the C-6 position. The structures of all compounds, including their relative stereochemistry, were determined by combined spectroscopic methods. The present compounds exhibited a significant inhibitory effect upon the growth of the malarial parasite Plasmodium falciparum.