Prefluostatin and New Urauchimycin Derivatives Produced by Streptomycete Isolates

Abstract

Abstract Guided by chemical screening, two new members of the antimycin group, urauchimycin C (1b) and D (1a), were isolated from the marine-derived Streptomyces sp. isolate B1751 and from a terrestrial strain AdM21, together with prefluostatin (2), a new natural derivative of isoprekinamycin (4). Their structures were established on the basis of NMR data and by comparison with known compounds. In the agar diffusion test, urauchimycin C (1b) and D (1a) were antibiotically inactive against some bacteria and fungi at a concentration of 25 μg per paper disk, while the isoprekinamycin derivative 2 showed weak cytotoxicity and moderate activity in the agar diffusion test against Bacillus subtilis, Mucor miehei, Escherichia coli and Staphylococcus aureus at concentrations of 20 μg per paper disk.