Open AccessFunctionalized Dioxonaphthoimidazoliums: A Redox Cycling Chemotype with Potent Bactericidal Activities against Mycobacterium tuberculosis
Author(s) -
Kevin Timothy Fridianto,
Ming Li,
Kiel Hards,
Dereje A. Negatu,
Gregory M. Cook,
Thomas Dick,
Yulin Lam,
MeiLin Go
Publication year - 2021
Publication title -
journal of medicinal chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.01
H-Index - 261
eISSN - 1520-4804
pISSN - 0022-2623
DOI - 10.1021/acs.jmedchem.1c01383
Subject(s) - chemistry , redox , biochemistry , lipophilicity , mycobacterium tuberculosis , reactive oxygen species , quinone , efflux , microbiology and biotechnology , isoniazid , bacteria , biology , tuberculosis , medicine , genetics , organic chemistry , pathology
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.