Design, synthesis and biological evaluation of 4-aminoquinoline-guanylthiourea derivatives as antimalarial agents.

Guanylthiourea (GTU) has been identified as an important antifolate antimalarial pharmacophore unit, whereas, 4-amino quinolones are already known for antimalarial activity. In the present work molecules carrying 4-aminoquinoline and GTU moiety have been designed using molecular docking analysis with PfDHFR enzyme and heme unit. The docking results indicated that the necessary interactions (Asp54 and Ile14) and docking score (-9.63 to -7.36 kcal/mmol) were comparable to WR99210 (-9.89 kcal/mol). From these results nine molecules were selected for synthesis. In vitro analysis of these synthesized compounds reveal that out of the nine molecules, eight show antimalarial activity in the range of 0.61-7.55 µM for PfD6 strain and 0.43-8.04 µM for PfW2 strain. Further, molecular dynamics simulations were performed on the most active molecule to establish comparative binding interactions of these compounds and reference ligand with Plasmodium falciparum dihydrofolate reductase (PfDHFR).

Design and synthesis of guanylthiourea derivatives as potential inhibitors of Plasmodium falciparum dihydrofolate reductase enzyme.

A new class of compounds based on S-benzylated guanylthiourea has been designed as potential PfDHFR inhibitors using computer aided methods (molecular electrostatic potential, molecular docking). Several compounds in this class have been synthesized starting from guanylthiourea and alkyl bromides. In vitro studies showed that two compounds from this class are active with the IC50 value of 100 µM and 400 nM.

Guanylthiourea derivatives as potential antimalarial agents: Synthesis, in vivo and molecular modelling studies.

Guanylthiourea (GTU) derivatives were identified as possible anti-malarial agents, recently, using in vitro studies on Plasmodium falciparum. This article gives an account of the in vivo anti-malarial activity of GTU derivatives against experimental rodent malaria. A total of 20 synthesized GTU derivatives were evaluated for in vivo antimalarial activity, out of which six showed encouraging results; one compound appeared to have curative potential. Molecular docking and molecular dynamics analysis were carried out to understand the molecular level interactions.