Identification of New Human Malaria Parasite Plasmodium falciparum Dihydroorotate Dehydrogenase Inhibitors by Pharmacophore and Structure-Based Virtual Screening

J Chem Inf Model. 2016 Mar 28;56(3):548-62. doi: 10.1021/acs.jcim.5b00680. Epub 2016 Mar 8.

Abstract

Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH), a key enzyme in the de novo pyrimidine biosynthesis pathway, which the Plasmodium falciparum relies on exclusively for survival, has emerged as a promising target for antimalarial drugs. In an effort to discover new and potent PfDHODH inhibitors, 3D-QSAR pharmacophore models were developed based on the structures of known PfDHODH inhibitors and the validated Hypo1 model was used as a 3D search query for virtual screening of the National Cancer Institute database. The virtual hit compounds were further filtered based on molecular docking and Molecular Mechanics/Generalized Born Surface Area binding energy calculations. The combination of the pharmacophore and structure-based virtual screening resulted in the identification of nine new compounds that showed >25% inhibition of PfDHODH at a concentration of 10 μM, three of which exhibited IC50 values in the range of 0.38-20 μM. The most active compound, NSC336047, displayed species-selectivity for PfDHODH over human DHODH and inhibited parasite growth with an IC50 of 26 μM. In addition to this, 13 compounds inhibited parasite growth with IC50 values of ≤ 50 μM, 4 of which showed IC50 values in the range of 5-12 μM. These compounds could be further explored in the identification and development of more potent PfDHODH and parasite growth inhibitors.

Publication types

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

MeSH terms

  • Animals
  • Dihydroorotate Dehydrogenase
  • Enzyme Inhibitors / pharmacology*
  • Humans
  • Oxidoreductases Acting on CH-CH Group Donors / antagonists & inhibitors*
  • Plasmodium falciparum / drug effects*
  • Plasmodium falciparum / enzymology
  • Quantitative Structure-Activity Relationship

Substances

  • Dihydroorotate Dehydrogenase
  • Enzyme Inhibitors
  • Oxidoreductases Acting on CH-CH Group Donors