Isopropyl( ene )-type cembrene diterpene an important secondary metabolite in soft coral Sinularia flexibilis of Tun Sakaran Marine Park, Malaysia

Two cembrane diterpenes; ( 3 S, 4S, II S, 12S, 1 E, 7 E)- 3, 4: 11, 12- bisepoxycembra-1, 7 -diene (1) and (1E,3E, 7E)-11,12-epoxycembra-1,3, 7-triene (2) were isolated from a population of Sinularia flexibilis collected from Kapikan Reef, Semporna, Sabah. The chemical structures were elucidated based on 1H-NMR and 13C-NMR spectroscopic data. This is the first record of cembranoid diterpenes isolated from the Malaysian soft coral genus Sinularia. Thesecembrenes could be used as chemotaxonomical markers and have also exhibited potent anti-bacterial activity against pathogenic Escherichia coli and Staphylococcus aureus.