Conversion of Quinine Derivatives into Biologically Active Ionic Liquids: Advantages, Multifunctionality, and Perspectives

In
this study, we demonstrate that quinine with confirmed antiviral
and antifeedant activity can be derivatized and formulated as multifunctional
ionic liquids which allow one to tune their biological, chemical,
and physical properties. Following the optimization of quinine alkylation,
pure 1-alkylquinine bromides with alkyl chain length ranging from
ethyl to dodecyl were synthesized and extensively characterized. In
the next step, these derivatives were combined with counterions of
natural origin, which resulted in the formation of naturally derived
ionic liquids. Our results indicate that the transformation of quinine
into ionic liquids may improve antifeedant properties by 265% compared
to the activity of quinine-free base. Moreover, unlike the majority
of known cases, the reduction of the alkyl chain length results in
a significant increase in this type of biological activity.