Isolation and Structure of Providencin: A Highly Oxygenated Diterpene Possessing a Unique Bicyclo[12.2.0]hexadecane Ring System from the Sea Plume <i>Pseudopterogorgia kallos</i>

Abstract

[structure: see text] Providencin (1) is a naturally occurring cytotoxin isolated from the Caribbean gorgonian octocoral Pseudopterogorgia kallos. Its highly oxygenated hexacyclic structure is based on a previously undescribed bicyclo[12.2.0]hexadecane ring system and was established through spectroscopic analysis and X-ray crystallographic analysis. Providencin (1) was shown to exhibit modest anticancer activity against human breast (MCF7), lung (NCI-H460), and CNS (SF-268) cancer cell lines.