Novel Antimalarial Tetrazoles and Amides Active against the Hemoglobin Degradation Pathway in Plasmodium falciparum

J Med Chem. 2021 Mar 11;64(5):2739-2761. doi: 10.1021/acs.jmedchem.0c02022. Epub 2021 Feb 23.

Abstract

Malaria control programs continue to be threatened by drug resistance. To identify new antimalarials, we conducted a phenotypic screen and identified a novel tetrazole-based series that shows fast-kill kinetics and a relatively low propensity to develop high-level resistance. Preliminary structure-activity relationships were established including identification of a subseries of related amides with antiplasmodial activity. Assaying parasites with resistance to antimalarials led us to test whether the series had a similar mechanism of action to chloroquine (CQ). Treatment of synchronized Plasmodium falciparum parasites with active analogues revealed a pattern of intracellular inhibition of hemozoin (Hz) formation reminiscent of CQ's action. Drug selections yielded only modest resistance that was associated with amplification of the multidrug resistance gene 1 (pfmdr1). Thus, we have identified a novel chemical series that targets the historically druggable heme polymerization pathway and that can form the basis of future optimization efforts to develop a new malaria treatment.

Publication types

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

MeSH terms

  • Amides / chemical synthesis
  • Amides / pharmacokinetics
  • Amides / pharmacology*
  • Antimalarials / chemical synthesis
  • Antimalarials / pharmacokinetics
  • Antimalarials / pharmacology*
  • Drug Resistance, Microbial / drug effects
  • Hemeproteins / antagonists & inhibitors
  • Hemoglobins / metabolism*
  • Hep G2 Cells
  • Humans
  • Molecular Structure
  • Parasitic Sensitivity Tests
  • Plasmodium falciparum / drug effects*
  • Plasmodium falciparum / metabolism
  • Small Molecule Libraries / chemical synthesis
  • Small Molecule Libraries / pharmacokinetics
  • Small Molecule Libraries / pharmacology
  • Structure-Activity Relationship
  • Tetrazoles / chemical synthesis
  • Tetrazoles / pharmacokinetics
  • Tetrazoles / pharmacology*

Substances

  • Amides
  • Antimalarials
  • Hemeproteins
  • Hemoglobins
  • Small Molecule Libraries
  • Tetrazoles
  • hemozoin