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

Four new cembrane diterpenes, 1,13-di-epi-13-acetoxy launine P (1), 13-oxo-thunbergol (2), isocrassumol B (3) and 7α, 8α-sarcophine (4), together with two known launine P (5) and sarcophytonin B (6), were isolated from the extract of the South China Sea soft coral Sarcophyton trocheliophorum. 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 1, 2 and 5 were found to exhibit weak antibacterial activity, while 6 showed strong inhibition activity against Staphylococcus aureus and Bacillus subtilis (MIC＜0.5 µg/mL). Compounds 2 showed moderate inhibitory effect against influenza A viruses H1N1 with IC50 of 17.8 μM.