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, (+)-7 α ,8 β -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.