2. Academic Validation
  3. Interrogating alkyl and arylalkylpolyamino (bis)urea and (bis)thiourea isosteres as potent antimalarial chemotypes against multiple lifecycle forms of Plasmodium falciparum parasites

Interrogating alkyl and arylalkylpolyamino (bis)urea and (bis)thiourea isosteres as potent antimalarial chemotypes against multiple lifecycle forms of Plasmodium falciparum parasites

  • Bioorg Med Chem. 2015 Aug 15;23(16):5131-43. doi: 10.1016/j.bmc.2015.01.036.
Bianca K Verlinden 1,  Marna de Beer 1,  Boobalan Pachaiyappan 2,  Ethan Besaans 1,  Warren A Andayi 1,  Janette Reader 1,  Jandeli Niemand 1,  Riette van Biljon 1,  Kiplin Guy 3,  Timothy Egan 4,  Patrick M Woster 2,  Lyn-Marie Birkholtz 5
Affiliations

Affiliations

  • 1 Department of Biochemistry, Faculty of Natural and Agricultural Sciences, Centre for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Pretoria 0028, South Africa.
  • 2 Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA.
  • 3 Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN, USA.
  • 4 Department of Chemistry, University of Cape Town, Medical School, Observatory 7925, South Africa.
  • 5 Department of Biochemistry, Faculty of Natural and Agricultural Sciences, Centre for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Pretoria 0028, South Africa. Electronic address: lbirkholtz@up.ac.za.
PMID: 25684422 DOI: 10.1016/j.bmc.2015.01.036
Abstract

A new series of potent potent aryl/alkylated (bis)urea- and (bis)thiourea polyamine analogues were synthesized and evaluated in vitro for their antiplasmodial activity. Altering the carbon backbone and terminal substituents increased the potency of analogues in the compound library 3-fold, with the most active compounds, 15 and 16, showing half-maximal inhibitory concentrations (IC50 values) of 28 and 30 nM, respectively, against various Plasmodium falciparum Parasite strains without any cross-resistance. In vitro evaluation of the cytotoxicity of these analogues revealed marked selectivity towards targeting malaria parasites compared to mammalian HepG2 cells (>5000-fold lower IC50 against the Parasite). Preliminary biological evaluation of the polyamine analogue antiplasmodial phenotype revealed that (bis)urea compounds target Parasite asexual proliferation, whereas (bis)thiourea compounds of the same series have the unique ability to block transmissible gametocyte forms of the Parasite, indicating pluripharmacology against proliferative and non-proliferative forms of the Parasite. In this manuscript, we describe these results and postulate a refined structure-activity relationship (SAR) model for antiplasmodial polyamine analogues. The terminally aryl/alkylated (bis)urea- and (bis)thiourea-polyamine analogues featuring a 3-5-3 or 3-6-3 carbon backbone represent a structurally novel and distinct class of potential antiplasmodials with activities in the low nanomolar range, and high selectivity against various lifecycle forms of P. falciparum parasites.

Keywords

(Bis)thiourea; (Bis)urea; Antimalarial drugs; Malaria; Plasmodium; Polyamine analogue.

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