Staphyloferrin A as siderophore-component in fluoroquinolone-based Trojan horse antibiotics

Org Biomol Chem. 2013 Jun 7;11(21):3461-8. doi: 10.1039/c3ob40162f. Epub 2013 Apr 11.

Abstract

A series of fluoroquinolone conjugates was synthesised by linking the carboxylic acid functionality of the carboxylate-type siderophore staphyloferrin A and its derivatives to the piperazinyl nitrogen of ciprofloxacin and norfloxacin via amide bond formation. Four siderophore-drug conjugates were screened against a panel of bacteria associated with infection in humans. Whilst no activity was found against ciprofloxacin- or norfloxacin-resistant bacteria, one of the conjugates retained antibacterial activity against fluoroquinolone-susceptible strains although the structure of its lysine-based siderophore component differs from that of the natural siderophore staphyloferrin A. In contrast, three ornithine-based siderophore conjugates showed significantly reduced activity against strains that are susceptible to their respective parent fluoroquinolones, regardless of the type of fluoroquinolone attached or chirality at the ornithine Cα-atom. The loss of potency observed for the (R)- and (S)-ornithine-based ciprofloxacin conjugates correlates with their reduced inhibitory activity against the target enzyme DNA gyrase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / chemical synthesis
  • Anti-Bacterial Agents / chemistry*
  • Anti-Bacterial Agents / pharmacology
  • Bacteria / drug effects
  • Carboxylic Acids / chemistry
  • Citrates / chemistry*
  • Fluoroquinolones / chemical synthesis
  • Fluoroquinolones / chemistry*
  • Fluoroquinolones / pharmacology
  • Humans
  • Models, Molecular
  • Ornithine / analogs & derivatives*
  • Ornithine / chemistry
  • Siderophores / chemistry*

Substances

  • Anti-Bacterial Agents
  • Carboxylic Acids
  • Citrates
  • Fluoroquinolones
  • Siderophores
  • staphyloferrin A
  • Ornithine