title: Efficient enzymatic preparation of hydroxycinnamates in ionic liquids enhances their antioxidant effect on lipoproteins oxidative modification.
abstract: Biocatalytic lipophilization of hydroxycinnamic acids was performed in several BF(4)(-) and PF(6)(-) imidazolium ionic liquids using immobilized lipases. The influence of various reaction parameters on the performance of the biocatalytic process was pointed out, using as model reaction the esterification of ferulic acid. The biocatalytic lipophilization strongly depended on the ion composition of ionic liquids used. Conversions and initial reaction rates were significantly higher in PF(6)(-) as compared with BF(4)(-) ionic liquids and commonly used organic solvents. The high enzyme stability and the relative solubility of substrate versus product in PF(6)(-) ionic liquids can account for the improved synthesis of lipophilic ferulates. These lipophilic derivatives, when used at a concentration of up to 400-fold lower than the parental compound, efficiently inhibited the oxidation of isolated LDL, HDL and total serum in vitro. Moreover, it has been shown for the first time that the lipophilic ferulates improve the antioxidant efficiency of the HDL(3c) towards LDL in vitro oxidation.
authors.affiliation: Laboratory of Enzyme Biotechnology, Department of Biological Applications and Technologies, University of Ioannina, 45110 Ioannina, Greece.
authors.forename: Maria H
authors.initials: MH
authors.lastname: Katsoura
authors.forename: Angeliki C
authors.initials: AC
authors.lastname: Polydera
authors.forename: Loukas D
authors.initials: LD
authors.lastname: Tsironis
authors.forename: Maria P
authors.initials: MP
authors.lastname: Petraki
authors.forename: Sladjana Kostić
authors.initials: SK
authors.lastname: Rajacić
authors.forename: Alexandros D
authors.initials: AD
authors.lastname: Tselepis
authors.forename: Haralambos
authors.initials: H
authors.lastname: Stamatis
mesh_terms: D020003:1-Octanol / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology*; D055162:Biocatalysis / Q000187:drug effects; D003373:Coumaric Acids / Q000378:metabolism*; D004800:Enzymes, Immobilized / Q000378:metabolism; D004951:Esterification / Q000187:drug effects; D062385:Hydroxybenzoates / Q000378:metabolism; D052578:Ionic Liquids / Q000378:metabolism*; D008049:Lipase / Q000378:metabolism*; D008074:Lipoproteins / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D012995:Solubility / Q000187:drug effects; D013379:Substrate Specificity / Q000187:drug effects
chemical_list: D000975:Antioxidants; D003373:Coumaric Acids; D004800:Enzymes, Immobilized; D062385:Hydroxybenzoates; D052578:Ionic Liquids; D008074:Lipoproteins; C004999:ferulic acid; D008049:Lipase; C017616:phenolic acid; D020003:1-Octanol