A new antibacterial lipopeptide found by UPLC-MS from an actinomycete Streptomyces sp. HCCB10043.

It is an attractive and interesting thing for us to mine the diversity of microbial metabolites by means of ultra performance liquid chromatography tandem quadrupole and time of flight high-resolution mass spectrometry. Through this method, two trace compounds, a new lipopeptide, named arylomycin A6 (1), and a known lipopeptide (arylomycin A5, 2) were found and isolated from an actinomycete Streptomyces parvus HCCB10043. The structure of the new lipopeptide was elucidated by a combination of 1D, 2D NMR (correlation spectroscopy, heteronuclear multiple quantum correlation and heteronuclear multiple bond coherence) techniques, high-resolution electrospray ionization mass spectrometry and MS/MS spectrometry and fatty acid analyses. Arylomycin A6 exhibited antibacterial activity against Staphylococcus epidermidis HCCB20256 with the minimum inhibitory concentration of 1 μg/mL. Till now, arylomycins are the third series of active secondary metabolites we found in S. parvus HCCB10043. The results strongly support and encourage the studies for mining trace natural active products from microorganisms like Streptomyces.