New Iron Twist to ChloroquineUpgrading Antimalarials with Immunomodulatory and Antimicrobial Features

Herein, upgraded chloroquine (CQ) derivatives capable
of overcoming Plasmodium resistance
and, at the same time, suppressing
excessive immune response and risk of concurrent bacteremia were developed.
Twelve new ferrocene–CQ hybrids tethered with
a small azathia heterocycle (1,3-thiazolidin-4-one, 1,3-thiazinan-4-one,
or 5-methyl-1,3-thiazolidin-4-one) were synthesized and fully characterized.
All hybrids were evaluated for their in vitro antiplasmodial, antimicrobial,
and immunomodulatory activities. Additional assays were performed
on selected hybrids to gain insights into their mode of action. Although
only hybrid 4a was more potent than the parent drug toward CQ-resistant Dd2 Plasmodium falciparum strain, several other hybrids (such as 6b, 6c, and 6d) manifested substantially improved antimicrobial
and immunomodulatory properties. Interesting structure–activity
relationship data were obtained, hinting at future research for the
development of new multitarget chemotherapies for malaria and other
infectious diseases complicated by drug resistance, bacterial co-infection,
and immune-driven pathology issues.