Novel Toxoplasma gondii inhibitor chemotypes

A. G. Sanford, T. T. Schulze, L. P. Potluri, R. M. Hemsley, J. J. Larson, A. K. Judge, S. J. Zach, X. Wang, S. A. Charman, J. L. Vennerstrom, P. H. Davis

Research output: Contribution to journalArticleResearchpeer-review

6 Citations (Scopus)


We profiled three novel T. gondii inhibitors identified from an antimalarial phenotypic high throughput screen (HTS) campaign: styryl 4-oxo-1,3-benzoxazin-4-one KG3, tetrahydrobenzo[b]pyran KG7, and benzoquinone hydrazone KG8. These compounds inhibit T. gondii in vitro with IC50 values ranging from 0.3 to 2 μM, comparable to that of 0.25 to 1.5 μM for the control drug pyrimethamine. KG3 had no measurable cytotoxicity against five mammalian cell lines, whereas KG7 and KG8 inhibited the growth of 2 of 5 cell lines with KG8 being the least selective for T. gondii. None of the compounds were mutagenic in an Ames assay. Experimental gLogD7.4 and calculated PSA values for the three compounds were well within the ranges predicted to be favorable for good ADME, even though each compound had relatively low aqueous solubility. All three compounds were metabolically unstable, especially KG3 and KG7. Multiple IP doses of 5 mg/kg KG7 and KG8 increased survival in a T. gondii mouse model. Despite their liabilities, we suggest that these compounds are useful starting points for chemical prospecting, scaffold-hopping, and optimization.

Original languageEnglish
Pages (from-to)107-111
Number of pages5
JournalParasitology International
Issue number2
Publication statusPublished - 1 Apr 2018


  • Anti-parasitics
  • Drug discovery
  • Lead compounds
  • Plasmodium falciparum
  • Toxoplasma gondii

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