Further chemical investigation of a marine-derived bacterium of the genus Streptomyces has led to the isolation of ansalactams B-D (1-3) along with the previously reported metabolite ansalactam A (4). Ansalactams B-D are significantly modified ansamycins, representing three new carbon skeletons and further illustrating the biosynthetic plasticity of the ansalactam class. Unlike ansalactam A, ansalactams B and D are penta- and hexacyclic metabolites, while ansalactam C illustrates an open polyene chain with a terminal carboxylic acid.
Bibliographical noteFunding Information:
The present study was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT and Future Planning (NRF- 2014R1A1A1003492 and NRF- 2016R1A2A1A05005078), and by the U.S. National Cancer Institute (NIH) under Grant No. R37CA044848 and Instrument Grant No. 1 S10 OD0106400-01A1 (HR?LC?MS, both to W.F.).
© 2016 American Chemical Society.