A small-molecule cell-based screen led to the identification of biphenylimidazoazines with highly potent and broad-spectrum anti-apicomplexan activity

Eur J Med Chem. 2014 Oct 22;89C:386-400. doi: 10.1016/j.ejmech.2014.10.057. [Epub ahead of print]

 

Moine E¹, Denevault-Sabourin C², Debierre-Grockiego F³, Silpa L⁴, Gorgette O⁵, Barale JC⁵, Jacquiet P⁶, Brossier F⁷, Gueiffier A⁸, Dimier-Poisson I³, Enguehard-Gueiffier C⁸.

 

An in vitro screening of the anti-apicomplexan activity of 51 compounds, stemming from our chemical library and from chemical synthesis, was performed. As a study model, we used Toxoplasma gondii (T. gondii), expressing β-galactosidase for the colorimetric assessment of drug activity on parasites cultivated in vitro. This approach allowed the validation of a new series of molecules with a biphenylimidazoazine scaffold as inhibitors of T. gondii growth in vitro. Hence, 8 molecules significantly inhibited intracellular replication of T. gondii in vitro, with EC₅₀ < 1 μM, while being non-toxic for human fibroblasts at these concentrations. Most attractive candidates were then selected for further biological investigations on other apicomplexan parasites (Neospora caninum, Besnoitia besnoiti, Eimeria tenella and Plasmodium falciparum). Finally, two compounds were able to inhibit growth of four different apicomplexans with EC₅₀ in the submicromolar to nanomolar range, for each parasite. These data, including the broad anti-parasite spectrum of these inhibitors, define a new generation of potential anti-parasite compounds of wide interest, including for veterinary application. Studies realized on E. tenella suggest that these molecules act during the intracellular development steps of the parasite. Further experiments should be done to identify the molecular target(s) of these compounds.
Copyright © 2014 Elsevier Masson SAS. All rights reserved.

KEYWORDS:

Anti-apicomplexan; Besnoitia besnoiti; Eimeria tenella; Imidazo[1,2-a]pyridine; Imidazo[1,2-b]pyridazine; Neospora caninum; Plasmodium falciparum; Toxoplasma gondii

PMID:

25462254

[PubMed - as supplied by publisher]