Discovery of Potent Benzofuran-Derived Diapophytoene Desaturase (CrtN) Inhibitors with Enhanced Oral Bioavailability for the Treatment of Methicillin-Resistant Staphylococcus aureus (MRSA) Infections

J Med Chem. 2016 Apr 14;59(7):3215-30. doi: 10.1021/acs.jmedchem.5b01984. Epub 2016 Apr 5.

Abstract

Blocking the staphyloxanthin biosynthesis process has emerged as a new promising antivirulence strategy. Previously, we first revealed that CrtN is a druggable target against infections caused by pigmented Staphylococcus aureus (S. aureus) and that naftifine was an effective CrtN inhibitor. Here, we identify a new type of benzofuran-derived CrtN inhibitor with submicromolar IC50 values that is based on the naftifine scaffold. The most potent analog, 5m, inhibits the pigment production of S. aureus Newman and three MRSA strains, with IC50 values of 0.38-5.45 nM, without any impact on the survival of four strains (up to 200 μM). Notably, compound 5m (1 μM) could significantly sensitize four strains to immune clearance and could effectively attenuate the virulence of three strains in vivo. Moreover, 5m was determined to be a weak antifungal reagent (MIC > 16 μg/mL). Combined with good oral bioavailability (F = 42.2%) and excellent safety profiles, these data demonstrate that 5m may be a good candidate for the treatment of MRSA infections.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Animals
  • Anti-Bacterial Agents / administration & dosage
  • Anti-Bacterial Agents / pharmacokinetics
  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Proteins / antagonists & inhibitors*
  • Benzofurans / chemistry*
  • Biological Availability
  • Drug Discovery
  • Enzyme Inhibitors / administration & dosage
  • Enzyme Inhibitors / pharmacokinetics
  • Enzyme Inhibitors / pharmacology*
  • Female
  • Male
  • Methicillin-Resistant Staphylococcus aureus / drug effects*
  • Mice
  • Mice, Inbred BALB C
  • Microbial Sensitivity Tests
  • Oxidoreductases / antagonists & inhibitors*
  • Rats
  • Rats, Sprague-Dawley
  • Staphylococcal Infections / drug therapy*
  • Staphylococcal Infections / microbiology
  • Tissue Distribution

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Benzofurans
  • Enzyme Inhibitors
  • CrtN protein, Staphylococcus aureus
  • Oxidoreductases
  • benzofuran