Cembranoid Diterpenes from the Soft Coral Lobophytum crassum and Their Anti-inflammatory Activities

Nine cembranoid diterpenes 1-9, including four new compounds, crassumols D-G (1-4), were isolated from the methanol extract of the Vietnamese soft coral Lobophytum crassum. Spectroscopic methods were used to elucidate the structures of these compounds. Compound 5 exhibited a potent inhibitory effect on tumor necrosis factor-alpha (TNF alpha)-induced nuclear factor-kappa B (NF-kappa B) transcriptional activation in HepG2 cells and significantly inhibited the mRNA expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in a dose-dependent manner.