Pentacyclic nitrofurans that rapidly kill nifurtimox-resistant trypanosomes

Area of Science:

• Medicinal Chemistry
• Parasitology
• Drug Discovery

Background:

• Reports indicate growing resistance to nifurtimox, a key drug for treating Trypanosoma brucei infections.
• There is an urgent need for novel therapeutic agents to combat drug-resistant trypanosomiasis.

Purpose of the Study:

• To evaluate antituberculosis nitrofuran isoxazolines as potential inhibitors of Trypanosoma brucei growth.
• To assess the efficacy of these compounds against both drug-susceptible and nifurtimox-resistant parasites.

Main Methods:

• In vitro susceptibility testing of T. brucei brucei against nitrofuran isoxazolines.
• Determination of growth inhibition concentrations (EC90), time-kill kinetics, and reversibility of inhibition.
• Assessment of P-glycoprotein-mediated exclusion for blood-brain barrier penetration.

Main Results:

• Nitrofuran isoxazolines demonstrated potent inhibition of T. brucei brucei proliferation at nanomolar concentrations.
• Pentacyclic nitrofurans were significantly more potent (100-fold) than nifurtimox.
• Activity was maintained against nifurtimox-resistant parasites, suggesting a novel activation mechanism.
• Compound 15 exhibited rapid, irreversible trypanocidal activity in vivo within 4 hours.

Conclusions:

• Pentacyclic nitrofuran isoxazolines are highly effective inhibitors of T. brucei brucei.
• These compounds show significant potential for treating both nifurtimox-susceptible and nifurtimox-resistant trypanosome infections.
• Further development of these agents is warranted for trypanosomiasis treatment.