Second generation steroidal 4-aminoquinolines are potent, dual-target inhibitors of the botulinum neurotoxin serotype A metalloprotease and P. falciparum malaria

J Med Chem. 2014 May 22;57(10):4134-53. doi: 10.1021/jm500033r. Epub 2014 May 1.

Abstract

Significantly more potent second generation 4-amino-7-chloroquinoline (4,7-ACQ) based inhibitors of the botulinum neurotoxin serotype A (BoNT/A) light chain were synthesized. Introducing an amino group at the C(3) position of the cholate component markedly increased potency (IC50 values for such derivatives ranged from 0.81 to 2.27 μM). Two additional subclasses were prepared: bis(steroidal)-4,7-ACQ derivatives and bis(4,7-ACQ)cholate derivatives; both classes provided inhibitors with nanomolar-range potencies (e.g., the Ki of compound 67 is 0.10 μM). During BoNT/A challenge using primary neurons, select derivatives protected SNAP-25 by up to 89%. Docking simulations were performed to rationalize the compounds' in vitro potencies. In addition to specific residue contacts, coordination of the enzyme's catalytic zinc and expulsion of the enzyme's catalytic water were a consistent theme. With respect to antimalarial activity, the compounds provided better IC90 activities against chloroquine resistant (CQR) malaria than CQ, and seven compounds were more active than mefloquine against CQR strain W2.

Publication types

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

MeSH terms

  • Aminoquinolines / chemical synthesis*
  • Aminoquinolines / pharmacology
  • Animals
  • Antimalarials / chemical synthesis*
  • Antimalarials / pharmacology
  • Botulinum Toxins, Type A / antagonists & inhibitors*
  • Chick Embryo
  • Chloroquine / pharmacology
  • Drug Resistance
  • Hep G2 Cells
  • Humans
  • Metalloproteases / drug effects*
  • Molecular Docking Simulation
  • Plasmodium falciparum / drug effects*
  • Protease Inhibitors / chemical synthesis*
  • Protease Inhibitors / pharmacology
  • Structure-Activity Relationship

Substances

  • Aminoquinolines
  • Antimalarials
  • Protease Inhibitors
  • Chloroquine
  • Metalloproteases
  • Botulinum Toxins, Type A