L‐Carnitine‐Based Bio‐Ionic Liquids as Antioxidants

Abstract The purpose of this research was to determine the antioxidant properties of ionic liquids containing an anion showing antioxidant activity and a cation of natural origin derived from L‐carnitine. Formation methods of ionic liquids based on direct protonation of an L‐carnitine zwitterion form were evaluated with the selected phenolic acids and L‐ascorbic acid. All received compounds were characterized, and the physicochemical properties significant to ionic liquid uses were measured (thermal stability and phase transitions). All research on antioxidant activity was conducted using commonly applied spectrophotometric methods, allowing for assessment of the neutralization ability of compounds regarding various radicals. The ferrous and cupric ion reduction ability and ferrous ion chelation of the ionic liquids were also examined. Furthermore, ionic liquid activity toward the enzyme xanthine oxidase responsible for the formation of reactive oxygen species in the body was determined.