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.