Polybrominated diphenyl ethers from the marine organisms Lendenfeldia dendyi and Sinularia dura with anti-MRSa activity

Bioassay-guided fractionation of the marine sponge Lendenfeldia dendyi and the soft coral Sinularia dura resulted in the isolation of five polybrominated diphenyl ethers (1–5). The structures of the isolated compounds were determined using spectroscopic methods (1D and 2D NMR) and HRMS analyses. The absolute structures of compounds 1 and 2 were confirmed by X-ray analysis. Antimicrobial testing of the isolated compounds along with the acetylated derivative of compound 2 (2a) indicated that they displayed a significant and selective activity against methicillin-resistant Staphylococcus aureus (MRSa) with IC50 values of