Unusual pyranosyl cembranoid diterpene from sarcophyton trocheliophorum

9-Hydroxy-10,11-dehydro-sarcotrocheliol (1), a new pyrane-based cembranoid diterpene, has been isolated along with three other known compounds, namely, sarcotrocheliol acetate (2), (+)-sarcophytol A (3), and (-)-sarcophytonin A (4), from the organic extract of the soft coral Sarcophyton trocheliophorum. The chemical structures of compounds 1-4 were determined on the basis of their 1D and 2D NMR [1H, 13C, 1H-1H correlation spectroscopy, heteronuclear multiple-quantum coherence, heteronuclear multiple-bond correlation, and nuclear Overhauser effect (NOE)] and mass spectra [electron ionization (EI), electrospray ionization, and high resolution mass spectrometry (HRMS)], and by comparison with related structures. The compounds 1-4 showed neither antimicrobial activity against 11 diverse tested microorganisms, nor cytotoxicity against brine shrimp, whereas the soft coral extract showed low cytotoxicity with a mortality rate of 1.7%.