Novel potent metallocenes against liver stage malaria

Area of Science:

• Medicinal Chemistry
• Parasitology
• Drug Discovery

Background:

• Primaquine is a key antimalarial drug.
• Developing new antimalarials is crucial due to resistance.
• Ferrocene conjugates offer novel chemical structures for drug development.

Purpose of the Study:

• To synthesize and evaluate novel primaquine-ferrocene conjugates (primacenes).
• To assess primacenes against various malaria parasite stages (blood, liver) and transmission.
• To identify structural features crucial for antimalarial activity.

Main Methods:

• Chemical synthesis of primaquine-ferrocene conjugates.
• In vitro screening against blood-stage and liver-stage malaria parasites.
• In vivo testing for host-vector transmission blocking.

Main Results:

• Primacenes with a basic aliphatic amine group retained transmission-blocking and blood-schizontocidal activities.
• All tested metallocenes showed comparable or improved liver-stage activity versus primaquine.
• Compound 7 (hexylferrocene conjugate) demonstrated ~45-fold higher liver-stage activity than primaquine.

Conclusions:

• Specific structural modifications in primacenes can preserve or enhance antimalarial properties.
• Ferrocene conjugation is a promising strategy for developing potent antimalarial drugs, especially against liver-stage malaria.
• Compound 7 represents a highly promising lead for further antimalarial drug development.