Sartrolides A-G and bissartrolide, new cembranolides from the South China Sea soft coral Sarcophyton trocheliophorum Marenzeller

The cembranolides sartrolides A-G (1-7) and the dimer bissartrolide (8) were isolated from Sarcophyton trocheliophorurn Marenzeller, along with three known analogues (9-11). Their stereochemistry was elucidated by spectroscopic analysis (IR, UV, NMR) and Flack single crystal X-ray diffraction analysis (for sarcrassin D and emblide), applied for the first time to this class of compounds. Sartrolides A-G (1-7) include an alpha,beta-unsaturated a-lactone and differ for the pattern of functionalization at C-1/C-8 moiety, including the rare 1Z,3E-diene system in sartrolide G. Bissartrolide (8) is only the third example of cembrane dimer found as a natural product. The known cembranolide 11 showed significant antibacterial activity against Staphylococcus aureus Newman strain. (C) 2013 Elsevier Ltd. All rights reserved.