Structural, stereochemical, and bioactive studies of cembranoids from Chinese soft coral &ITSarcophyton trocheliophorum&IT

A series of highly oxidative new cembranoids with diverse structural features such as a dienoate moiety (sarcophytonolides S - U, 1-3) or an alpha,beta-unsaturated epsilon-lactone (sartrolides H - J, 4-6) were obtained from Hainan soft coral Sarcophyton trocheliophorum, along with known related analogues 7-13. It is an extremely challenging work to determine the absolute configurations of these metabolites. For compounds 1, 3 and 4, solution TDDFT calculation of ECD and specific rotation were applied in combination with conformational analysis and NMR data to determine their relative and absolute configurations, leading to the revision of relative configuration of 14. The absolute configurations of compounds 8-10 were determined by the solid-state TDDFT-ECD approach, and that of 8 was further confirmed by singlecrystal X-ray diffraction experiment with Cu K alpha radiation. In the bioassays, compound 8 exhibited not only moderate protein tyrosine phosphatase 1B (PTP1B) inhibitory activity (IC50 = 15.4 mu M) but also moderate antibacterial activity against Staphylococcus aureus Newman strain (MIC50 = 250 mu M). (C) 2018 Elsevier Ltd. All rights reserved.