Incorporation of basic side chains into cryptolepine scaffold: structure-antimalarial activity relationships and mechanistic studies

J Med Chem. 2011 Feb 10;54(3):734-50. doi: 10.1021/jm101383f. Epub 2011 Jan 5.

Abstract

The synthesis of cryptolepine derivatives containing basic side-chains at the C-11 position and their evaluations for antiplasmodial and cytotoxicity properties are reported. Propyl, butyl, and cycloalkyl diamine side chains significantly increased activity against chloroquine-resistant Plasmodium falciparum strains while reducing cytotoxicity when compared with the parent compound. Localization studies inside parasite blood stages by fluorescence microscopy showed that these derivatives accumulate inside the nucleus, indicating that the incorporation of a basic side chain is not sufficient enough to promote selective accumulation in the acidic digestive vacuole of the parasite. Most of the compounds within this series showed the ability to bind to a double-stranded DNA duplex as well to monomeric hematin, suggesting that these are possible targets associated with the observed antimalarial activity. Overall, these novel cryptolepine analogues with substantially improved antiplasmodial activity and selectivity index provide a promising starting point for development of potent and highly selective agents against drug-resistant malaria parasites.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antimalarials / chemical synthesis*
  • Antimalarials / chemistry
  • Antimalarials / pharmacology
  • Cell Line, Tumor
  • Chlorocebus aethiops
  • Chloroquine / pharmacology
  • Cysteine Endopeptidases / chemistry
  • Cysteine Proteinase Inhibitors / chemical synthesis
  • Cysteine Proteinase Inhibitors / chemistry
  • Cysteine Proteinase Inhibitors / pharmacology
  • DNA / chemistry
  • Drug Resistance
  • Erythrocytes / drug effects
  • Erythrocytes / parasitology
  • Hemin / chemistry
  • Humans
  • Indole Alkaloids / chemical synthesis*
  • Indole Alkaloids / chemistry
  • Indole Alkaloids / pharmacology
  • Mefloquine / pharmacology
  • Oligonucleotides / chemistry
  • Plasmodium falciparum / drug effects
  • Pyrimethamine / pharmacology
  • Quinolines / chemical synthesis*
  • Quinolines / chemistry
  • Quinolines / pharmacology
  • Structure-Activity Relationship
  • Vero Cells

Substances

  • Antimalarials
  • Cysteine Proteinase Inhibitors
  • Indole Alkaloids
  • Oligonucleotides
  • Quinolines
  • cryptolepine
  • Hemin
  • Chloroquine
  • DNA
  • Cysteine Endopeptidases
  • falcipain 2
  • falcipain 3
  • Mefloquine
  • Pyrimethamine