Cembrane-type diterpenoids are among the most frequently encountered natural products from the soft corals of the genus Lobophytum. In the course of our investigation to identify anti-inflammatory constituents from a wild-type soft coral Lobophytum crassum, two new cembranoids, lobophyolide A (1) and B (2), along with five known compounds (3–7), were isolated. The structures of these natural products were identified using NMR and MS spectroscopic analyses. Compound 1 was found to possess the first identified α-epoxylactone group among all cembrane-type diterpenoids. The in vitro anti-inflammatory effect of compounds 1–5 was evaluated. The results showed that compounds 1–5 not only reduced IL-12 release, but also attenuated NO production in LPS-activated dendritic cells. Our data indicated that the isolated series of cembrane-type diterpenoids demonstrated interesting structural features and anti-inflammatory activity which could be further developed into therapeutic entities.

A new polyoxygenated briarane diterpenoid, briarenol B (1), was isolated from the octocoral Briareum excavatum and its structure determined from spectroscopic data. In RAW264.7 cells, a macrophage-like murine cell line, briarane B (1) was found to enhance the protein expression of pro-inflammatory cyclooxygenase (COX-2) and inducible nitric oxide synthase (iNOS) in cells stimulated by lipopolysaccharide (LPS).