Cembrane-type diterpenoids from the South China Sea soft coral

ABSTRACT

Eight cembrane-type diterpenoids, namely, (+)-(6)-6-hydroxyisosarcophytoxide (), (+)-(6)-6-acetoxyisosarcophytoxide (), (+)-17-hydroxyisosarcophytoxide (), sarcomililatins A-D (-), and sarcomililatol (), were isolated from the soft coral collected from Weizhou Island, Guangxi Autonomous Region, together with 2 known related analogues, (+)-isosarcophytoxide () and (+)-isosarcophine (). The structures of these compounds were elucidated by a combination of detailed spectroscopic analyses, chemical methods, and comparison with reported data. The absolute configuration of compound was established by the modified Mosher׳s method, while the absolute configurations of compounds and were assigned by electronic circular dichroism (ECD) spectroscopy and that of compound was established by time-dependent density functional theory electronic circular dichroism (TD-DFT ECD) calculation. In bioassays, compound displayed significant cytotoxicity against the human cancer cell lines human promyelocytic leukemia cells (HL-60) and human lung adenocarcinoma cells (A-549) with IC values of 0.78±0.21 and 1.26±0.80 μmol/L, respectively. Compounds and also showed moderate inhibitory effects on the TNF-induced Nuclear factor kappa B (NF-B, a therapeutical target in cancer) activation, showing IC values of 35.23±12.42 and 22.52±4.44 μmol/L, respectively.