Conjugates of 2,4-Dihydroxybenzoate and Salicylhydroxamate and Lipocations Display Potent Antiparasite Effects by Efficiently Targeting the Trypanosoma brucei and Trypanosoma congolense Mitochondrion

J Med Chem. 2017 Feb 23;60(4):1509-1522. doi: 10.1021/acs.jmedchem.6b01740. Epub 2017 Feb 9.

Abstract

We investigated a chemical strategy to boost the trypanocidal activity of 2,4-dihydroxybenzoic acid (2,4-DHBA)- and salicylhydroxamic acid (SHAM)-based trypanocides with triphenylphosphonium and quinolinium lipophilic cations (LC). Three series of LC conjugates were synthesized that were active in the submicromolar (5a-d and 10d-f) to low nanomolar (6a-f) range against wild-type and multidrug resistant strains of African trypanosomes (Trypanosoma brucei brucei and T. congolense). This represented an improvement in trypanocidal potency of at least 200-fold, and up to >10 000-fold, compared with that of non-LC-coupled parent compounds 2,4-DHBA and SHAM. Selectivity over human cells was >500 and reached >23 000 for 6e. Mechanistic studies showed that 6e did not inhibit the cell cycle but affected parasite respiration in a dose-dependent manner. Inhibition of trypanosome alternative oxidase and the mitochondrial membrane potential was also studied for selected compounds. We conclude that effective mitochondrial targeting greatly potentiated the activity of these series of compounds.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Drug Discovery
  • Humans
  • Hydroxybenzoates / chemistry
  • Hydroxybenzoates / pharmacology*
  • Membrane Potential, Mitochondrial / drug effects
  • Mitochondria / drug effects
  • Salicylamides / chemistry
  • Salicylamides / pharmacology*
  • Trypanocidal Agents / chemistry
  • Trypanocidal Agents / pharmacology*
  • Trypanosoma brucei brucei / drug effects*
  • Trypanosoma brucei brucei / metabolism
  • Trypanosoma congolense / drug effects*
  • Trypanosoma congolense / metabolism
  • Trypanosomiasis, African / drug therapy

Substances

  • Hydroxybenzoates
  • Salicylamides
  • Trypanocidal Agents
  • salicylhydroxamic acid
  • beta-resorcylic acid