Antibacterial angucyclinone and α-pyrone derivatives from desert-derived Nocardiopsis dassonvillei HDN 154151.

One new angucyclinone derivative, Kanglemycin N (1), and two new biogenetically related α-Pyrones, nocapyrones U-V (2-3), were isolated from a desert-derived Actinomycete Nocardiopsis dassonvillei HDN 154151. Their structures, including absolute configurations, were elucidated by extensive NMR, MS, and ECD analyses. Compound 1 exhibited potent antibacterial activity against Bacillus subtilis, Proteus sp., Vibrio Parahaemolyticus, Escherichia coli and Methicillin-resistant Staphylococcus aureus (MRSA) with MIC values ranging from 0.39 μM to 1.56 μM, and notably the effect of 1 against MRSA significantly exceeded the positive control ciprofloxacin. In addition, compound 1 also showed moderate cytotoxic activity against H69AR, MDA-MB-231, ASPC-1 and K562 cell lines, with IC 50 values of 10.46, 8.78, 9.28 and 8.61 μM, respectively.