||Marine invertebrates have been found to be a rich source of bioactive secondary metabolites. In order to discover bioactive compounds, we have studied the chemical constituents from the organic extracts of Formosan soft corals, Sarcophyton cherbonnieri. The study on the chemical constituents of the ethyl acetate extract of Sarcophyton cherbonnieri has led to the isolation of sixteen natural cembrane-type diterpenoids, compounds 1–16, including fifteen new compounds, cherbonolide A-N (2–15) and bischerbolide peroxide (16), along with one known compound 1, isosarcophine. |
The structures of these compounds 1-16 were established by detailed spectroscopic data analysis comprising IR, UV, specific optical rotations, circular dichroism, MS, 1D NMR, 2D NMR, and by comparison of the physical and spectral data with those of the related known compounds. The absolute configuration of 2 and 4 were determined using a modified Mosher’s method and the structures of 3, 6 and 10 were further established by organic methods. 15 is a rare cembranoid of 12, 17-ether linkage skeleton. 16 is discovered to be the first skeleton that two cembranoid were connected by peroxide group.
The cytotoxicity of compounds 1–16 against the A549 (human lung adenocarcinoma), DLD-1 (human colorectal adenocarcinoma), and HuCCT-1 (human intrahepatic cholangiocarcinoma) tumor cell lines was determined. The results didn’t show cytotoxic activity.