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Abstract: Chemical investigation of the soft coral Lobophytum durum resulted in the isolation of seven new cembranolides, durumolides F–L (1–7), as well as one previously characterized cembranolides, sinularolide D (8). The molecular structures of these isolated metabolites were determined mainly through NMR techniques and HRESIMS analysis. Moreover, the absolute configurations of 1 and 5 were established by application of modified Mosher’s method. The antibacterial activities, anti-inflammatory effects, and anti-HCMV (Human cytomegalovirus) endonuclease activity of metabolites 1–8 were also evaluated in vitro. Anti-inflammatory activity of metabolites 1 and 6 (10μM) significantly reduced the levels of the iNOS protein to 0.8±0.6% and 5.7±2.2%, respectively, and COX-2 protein to 47.8±9.0% and 71.6±5.8%, respectively. Metabolites 1–8 (100μg/disk) exhibited weak antibacterial activity against Salmonella enteritidis. [Copyright &y& Elsevier]

Using a bioactivity-guided fractionation procedure, five cembranolides, 11- epi -sinulariolide acetate ( 1 ), 11-dehydrosinulariolide ( 2 ), sinulariolide ( 3 ), dihydrosinularin ( 4 ), and 3,4:8,11-bisepoxy-7-acetoxycembra-15(17)-en-1,12-olide ( 5 ), along with two nucleosides, 2′-deoxyadenosine and thymidine, were isolated from the Formosan soft coral Sinularia flexibilis . Moreover, 7,8-epoxy-11- epi -sinulariolide acetate ( 1a ), 11-sinulariolide acetate ( 3a ), dihydrosinulariolide ( 3b ), 3,4:8,11-bisepoxy-7-hydroxycembra-15(17)-en-1,12-olide ( 3c ), 11-acetoxyl-15(17)-dihydrosinulariolide ( 3d ), 7,8-epoxy-11-sinulariolide acetate ( 3e ), and 3,4:8,11-bisepoxy-7-hydroxycembra-15(17)-dihydro-1,12-olide ( 3f ) were derived from compounds 1 and 3 , respectively. These structures were deduced on the basis of physical and chemical evidence. Among them, 1a , 3d , 3e , and 3f are new cembranolide analogues. The structure of compound 1 was further confirmed by X-ray analysis. In addition, the isolated cembranolides and the analogues under went a cytotoxicity assay, and the structure-activity relationship (SAR) of these compounds was studied. [ABSTRACT FROM AUTHOR]