Bacilotetrins A and B, Anti-Staphylococcal Cyclic-Lipotetrapeptides from a Marine-Derived Bacillus subtilis

J Nat Prod. 2017 Nov 22;80(11):2889-2892. doi: 10.1021/acs.jnatprod.7b00356. Epub 2017 Nov 8.

Abstract

LC-MS and NMR spectroscopy guided metabolic profiling and dereplication of a crude extract obtained from the fermentation of a marine-derived bacterium, Bacillus subtilis, followed by chromatographic isolation yielded two new cyclic-lipotetrapeptides, bacilotetrins A (1) and B (2). Based on extensive 1D and 2D NMR and high-resolution ESIMS data analysis, the structures of 1 and 2 were elucidated, revealing the unique structures of these lipopeptides consisting of three leucines and a glutamic acid residue cyclized with a lipophilic 3-hydroxy fatty acid. The absolute stereochemistries at selected stereocenters in 1 and 2 were assigned by chemical derivatization and comparison to literature data. Compounds 1 and 2 exhibited anti-MRSA activity with MIC values of 8 to 32 μg/mL. However, these compounds showed no cytotoxicity when tested against prostate and liver cancer cell lines using the standard SRB assay.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus subtilis / chemistry*
  • Humans
  • Lipopeptides / chemistry
  • Lipopeptides / isolation & purification*
  • Lipopeptides / pharmacology*
  • Marine Biology
  • Methicillin-Resistant Staphylococcus aureus / drug effects*
  • Microbial Sensitivity Tests
  • Molecular Structure
  • Nuclear Magnetic Resonance, Biomolecular

Substances

  • Lipopeptides
  • bacilotetrin A
  • bacilotetrin B