Sinugyrosanolide A, an unprecedented C-4 norcembranoid, from the Formosan soft coral Sinularia gyrosa

Chemical investigations on the acetone extract of the Formosan soft coral Sinularia gyrosa have obtained a novel C-4 norcembranoid possessing an unprecedented tricyclo[9.3.0.03,8]tetradecane skeleton, namely sinugyrosanolide A. The NMR spectroscopic data of the novel norcembranoid were completely assigned by using a combination of 2D NMR experiments including 1H–1H COSY, HSQC, HMBC, and NOESY. The cytotoxicities, anti-HCMV (human cytomegalovirus) endonuclease activities and antibacterial activities were evaluated in vitro. It showed moderate cytotoxicity against P-388 (mouse lymphocytic leukemia) cancer cell line with an EC50 of 11.8μM.