Discovery of Potent and Selective Halogen-Substituted Imidazole-Thiosemicarbazides for Inhibition of Toxoplasma gondii Growth In Vitro via Structure-Based Design

Molecules. 2019 Apr 24;24(8):1618. doi: 10.3390/molecules24081618.

Abstract

Employing a simple synthetic protocol, a series of highly effective halogen-substituted imidazole-thiosemicarbazides with anti-Toxoplasma gondii effects against the RH tachyzoites, much better than sulfadiazine, were obtained (IC50s 10.30-113.45 µg/mL vs. ~2721.45 µg/mL). The most potent of them, 12, 13, and 15, blocked the in vitro proliferation of T. gondii more potently than trimethoprim (IC50 12.13 µg/mL), as well. The results of lipophilicity studies collectively suggest that logP would be a rate-limiting factor for the anti-Toxoplasma activity of this class of compounds.

Keywords: anti-Toxoplasma gondii activity; cytotoxicity; selectivity ratio; structure-activity relationship (SAR) analysis; thiosemicarbazides.

MeSH terms

  • Animals
  • Halogens / chemistry
  • Humans
  • Imidazoles / chemistry
  • Imidazoles / pharmacology
  • Semicarbazides / chemical synthesis*
  • Semicarbazides / chemistry
  • Structure-Activity Relationship*
  • Sulfadiazine / pharmacology
  • Toxoplasma / drug effects*
  • Toxoplasma / pathogenicity
  • Toxoplasmosis / drug therapy*
  • Toxoplasmosis / parasitology

Substances

  • Halogens
  • Imidazoles
  • Semicarbazides
  • Sulfadiazine
  • thiosemicarbazide
  • imidazole