Two new cembrane-type diterpenoids, lobophytins A (1) and B (3), and four new prostaglandins, (5E)-PGB2 (10), (5E)-13,14-dihydro-PGB2 (11), 13,14-dihydro-PGB2 (12) and 13,14-dihydro-PGB2-Me (13), together with ten known compounds were isolated from the soft coral Lobophytum sarcophytoides. The structures of these new secondary metabolites were identified by high resolution mass spectrometry (HR-ESIMS), nuclear magnetic resonance (NMR) and electron circular dichroism (ECD) analyses, as well as the modified Mosher's method. Compounds 6, 7, 9, 10, 12, 13, 15 and 16 showed potential anti-inflammatory activity by inhibiting the production of nitric oxide (NO) in RAW264.7 cells that were activated by lipopolysaccharide, with IC50 values ranging from 7.1 to 32.1 μM and were better than the positive control indomethacin, IC50 = 39.8 μM.
Keywords: anti-inflammatory; cembrane-type diterpenoid; prostaglandin; soft coral.