Functionalized Dioxonaphthoimidazoliums: A Redox Cycling Chemotype with Potent Bactericidal Activities against Mycobacterium tuberculosis

J Med Chem. 2021 Nov 11;64(21):15991-16007. doi: 10.1021/acs.jmedchem.1c01383. Epub 2021 Oct 27.

Abstract

Disruption of redox homeostasis in mycobacteria causes irreversible stress induction and cell death. Here, we report the dioxonaphthoimidazolium scaffold as a novel redox cycling antituberculosis chemotype with potent bactericidal activity against growing and nutrient-starved phenotypically drug-resistant nongrowing bacteria. Maximal potency was dependent on the activation of the redox cycling quinone by the positively charged scaffold and accessibility to the mycobacterial cell membrane as directed by the lipophilicity and conformational characteristics of the N-substituted side chains. Evidence from microbiological, biochemical, and genetic investigations implicates a redox-driven mode of action that is reliant on the reduction of the quinone by type II NADH dehydrogenase (NDH2) for the generation of bactericidal levels of the reactive oxygen species (ROS). The bactericidal profile of a potent water-soluble analogue 32 revealed good activity against nutrient-starved organisms in the Loebel model of dormancy, low spontaneous resistance mutation frequency, and synergy with isoniazid in the checkerboard assay.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antitubercular Agents / chemistry
  • Antitubercular Agents / pharmacokinetics
  • Antitubercular Agents / pharmacology*
  • Bacterial Proteins / metabolism
  • Cell Wall / drug effects
  • Genes, Reporter
  • Imidazoles / chemistry
  • Imidazoles / pharmacokinetics
  • Imidazoles / pharmacology*
  • Microbial Sensitivity Tests
  • Mycobacterium tuberculosis / drug effects*
  • Mycobacterium tuberculosis / metabolism
  • NADH Dehydrogenase / metabolism
  • Oxidation-Reduction
  • Rats
  • Reactive Oxygen Species / metabolism
  • Structure-Activity Relationship
  • Up-Regulation

Substances

  • Antitubercular Agents
  • Bacterial Proteins
  • Imidazoles
  • Reactive Oxygen Species
  • NADH dehydrogenase II
  • NADH Dehydrogenase