Heterolactone and Heterolactams A–M, Verticillane Diterpenoids with Anti-Inflammatory and Hepatoprotective Activities from the Soft Coral <i>Heteroxenia ghardaqensis</i>

Fourteen new verticillane diterpenoids, heterolactone (1) and heterolactams A–M (2–14), were isolated from the soft coral Heteroxenia ghardaqensis. They structurally share the same 6/12 bicyclic carbon skeleton that is not commonly encountered in marine organisms. The structures, including the absolute configurations, were determined by extensive spectroscopic analysis, single-crystal X-ray diffraction analysis, calculated ECD spectra, and DP4+ probability analyses. Compounds 5, 8, and 9 showed anti-inflammatory activities, and 2, 8, and 12 displayed hepatoprotective activities in zebrafish assays.