Pyrane-based cembranoid and 2-dehydro-4-peroxy-sarcophine: two new diterpenes from Sarcophyton glaucum

Soft corals, particularly Sarcophyton sp. are rich in metabolites with variety of biological activities. In this study, a pyran-based 9-exo-methylene-10-hydroxy-sarcotrocheliol (1) and 2-dehydro-4-peroxy-sarcophine (2), two new cembranoide diterpenes, were isolated together with 9-hydroxy-10,11-dehydro-sarcotrocheliol, sarcotrocheliol, sarcotrocheliol acetate, sarcophine, (+)-7α,8β-dihydroxydeepoxysarcophine, (±)-sarcophytonine B, and peridinin from the organic extract of Sarcophyton glaucum collected at the coasts of Hurghada, Egypt. The structures of the new diterpenes 1-2 were identified based on cumulative analyses of HRESIMS and NMR (1D/2D NMR) spectra. The relative configurations of both compounds were verified by NOESY spectra and comparison with our recently reported analogues. The compounds showed no antimicrobial activity against a set of diverse tested microorganisms.