New Casbane and Cembrane Diterpenoids from an Okinawan Soft Coral, Lobophytum sp.

A new rare casbane-type diterpenoid 1 and two new cembrane diterpenoids 2, 3 were isolated from an Okinawan soft coral, Lobophytum sp., together with four known cembrane diterpenoids 4-7. Their structures were elucidated by extensive analysis of spectroscopic data (1D and 2D NMR, IR, and MS) and a molecular modeling study. The new isolates showed weak anti-bacterial activity, mild cytotoxicity against HCT116 cells, and anti-inflammatory effect in LPS/IFN-γ-stimulated RAW 264.7 macrophage cells.