Youssoufenes A2 and A3, Antibiotic Dimeric Cinnamoyl Lipids from the Δ dtlA Mutant of a Marine-Derived Streptomyces Strain.

Two new dimeric cinnamoyl lipids (CL) featuring with an unusual dearomatic carbon-bridge, named youssoufenes A2 ( 1 ) and A3 ( 2 ), were isolated from the Δ dtlA mutant strain of marine-derived Streptomyces youssoufiensis OUC6819. Structures of the isolated compounds were elucidated based on extensive MS and NMR spectroscopic analyses, and their absolute configurations were determined by combination of the long-range NOE-based ¹ H- ¹ H distance measurements and ECD calculations. Compounds 1 and 2 exhibited moderate growth inhibition against multi-drug-resistant Enterococcus faecalis CCARM 5172 with an MIC value of 22.2 μM.