Four new cembranoids from the South China Sea soft coral Sarcophyton trocheliophorum .

Four new cembrane diterpenes, 1,13-di--13-acetoxy launine P (), 13-oxo-thunbergol (), isocrassumol B () and 7α, 8α-sarcophine (), together with two known launine P ( and sarcophytonin B (), were isolated from the extract of the South China Sea soft coral . The structures were elucidated by spectroscopic analysis, ECD analysis and comparison with literature data. All compounds were tested for their antimicrobial activity and antiviral activity. Compounds , and were found to exhibit weak antibacterial activity, while showed strong inhibition activity against and (MIC＜0.5 µg/mL). Compounds showed moderate inhibitory effect against influenza A viruses H1N1 with IC of 17.8 μM.