Antiplasmodial cembradiene diterpenoids from a Southwestern Caribbean gorgonian octocoral of the genus Eunicea

Five new representatives of the cembrane class of marine natural products have been isolated as minor metabolites from an undescribed species of Eunicea, a sea whip collected near the Colombian Southwestern Caribbean Sea. The structure of the crystalline metabolite was solved by single-crystal X-ray diffraction analysis. Structures could then be proposed for cembradienes by comprehensive spectral analyses involving 2D NMR, IR, UV, and high-resolution mass spectrometry, as well as chemical interconversion studies. Compound exhibited weak cytotoxicity in the NCI 3-cell line panel human cancer screening program, whereas compounds , and displayed significant antiplasmodial activity against Plasmodium falciparum.