Structure-Activity Relationships of 3-Hydroxypropanamidines (HPAs) with Potent In Vivo Antimalarial Activity

Area of Science:

• Medicinal Chemistry
• Parasitology
• Drug Discovery

Background:

• Drug-resistant malaria poses a significant global health threat.
• Novel therapeutic strategies are urgently needed to combat resistant Plasmodium falciparum strains.

Purpose of the Study:

• To synthesize and evaluate novel 3-hydroxy-propanamidine (HPA) analogs as potential antimalarial agents.
• To assess the in vitro and in vivo efficacy and safety of promising HPA compounds.

Main Methods:

• Synthesis and chemical modification of HPA analogs.
• In vitro testing against drug-sensitive and resistant Plasmodium falciparum isolates.
• Cytotoxicity assays using human HepG2 cell line.
• Inhibition assays for hemozoin formation.
• In vivo antimalarial activity testing in Plasmodium berghei mouse models.
• Pharmacokinetic profiling of lead compounds.

Main Results:

• Several HPA analogs exhibited potent in vitro growth inhibition of P. falciparum.
• The most active compound, HPA 7d, showed significant inhibition of hemozoin formation with low IC50 values.
• HPA 7d demonstrated parasite selectivity, with no observed cytotoxicity in HepG2 cells.
• In vivo studies revealed dose-dependent curative activity of HPA 7d in a mouse model without toxicity.
• HPA 7d exhibited favorable pharmacokinetic properties, including rapid onset and slow elimination.

Conclusions:

• Novel HPA analogs represent a promising class of antimalarial drug candidates.
• HPA 7d displays significant potential for treating drug-resistant malaria due to its efficacy, selectivity, and favorable pharmacokinetic profile.
• Further development of HPA 7d is warranted for malaria treatment.