Biological evaluation of newly synthesized quinoline-based compound PPQ-8 in acute and chronic toxoplasmosis: An experimental study

Exp Parasitol. 2019 Nov:206:107756. doi: 10.1016/j.exppara.2019.107756. Epub 2019 Sep 5.

Abstract

Toxoplasma gondii is a widely distributed protozoan parasite, which affects worm-blooded animals including human. The commonest chemotherapeutics used for treatment of symptomatic toxoplasmosis have numerous adverse effects. Thus there is an eminent need to develop new therapeutic agents. Here we described the therapeutic efficacy of 4-(2-chloroquinolin-3-yl)-6-(2,5-dimethoxyphenyl)-2-oxo-1,2-dihydropyridine-3-carbonitrile (PPQ-8); a quinoline-related compound in a mouse model of acute and chronic toxoplasmosis. In acute infection, PPQ-8 decreased the parasite load in liver and spleen with amelioration of the hepatic and splenic pathology. In addition, recovered tachyzoites showed distorted shapes, reduced sizes, irregularities, surface protrusions, erosions and peeling besides apical region distortion when seen by scanning electron microscopy. In chronic toxoplasmosis, PPQ-8 produced degeneration and reduction of the brain cysts without stimulating a damaging inflammatory response within the brain. In both models acute and chronic, PPQ-8 prolonged the survival time of mice. These findings hold promise for the development of a novel anti-toxoplasmosis drug using PPQ-8, but further in vivo studies should be carried out to elucidate PPQ-8 mechanism of action and to report its efficacy in combination with other anti-toxoplasmosis agents.

Keywords: Chronic toxoplasmosis; Quinolines; Scanning electron microscopy; Survival rate; Toxoplasma gondii.

MeSH terms

  • Acute Disease
  • Analysis of Variance
  • Animals
  • Ascitic Fluid / parasitology
  • Brain / parasitology
  • Brain / pathology
  • Chronic Disease
  • Female
  • Kaplan-Meier Estimate
  • Liver / parasitology
  • Liver / pathology
  • Mice
  • Microscopy, Electron, Scanning
  • Normal Distribution
  • Quinolines / chemical synthesis
  • Quinolines / chemistry
  • Quinolines / therapeutic use*
  • Quinolines / toxicity
  • Random Allocation
  • Spleen / parasitology
  • Spleen / pathology
  • Toxoplasma / drug effects
  • Toxoplasma / pathogenicity*
  • Toxoplasma / ultrastructure
  • Toxoplasmosis, Animal / drug therapy*
  • Toxoplasmosis, Animal / parasitology

Substances

  • Quinolines