title: Kinetic and stoichiometry of the reaction of chlorogenic acid and its alkyl esters against the DPPH radical.
abstract: The lipophilization of polar antioxidants such as phenolics is an efficient way to enhance their solubility in apolar media. Thus, in emulsified systems, lipophilized antioxidants are supposed to locate at the lipid/aqueous phase interface and to lead to a better protection of unsaturated lipids. Herein, the antiradical activity of chlorogenic acid (5-CQA) and its corresponding esters with seven fatty alcohols (from methanol to eicosanol) have been achieved using the well-known 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Hydrophobation was shown to significantly improve the antiradical activity of 5-CQA esters which reached a maximum for butyl- and octyl-chlorogenate. In addition, for both 5-CQA and its esters, it was demonstrated that the global mechanism of DPPH* stabilization proceeded likely by electron transfer (ET), while it appeared that the pathways of DPPH* stabilization were different between 5-CQA and its esters, as confirmed by the LC-MS characterization of reaction products. Finally, strong differences were found between the tested molecules allowing the proposal of different DPPH* stabilization pathways by electron transfer for 5-CQA and its esters.
authors.affiliation: CIRAD PERSYST, Joint Research Unit on Agropolymers Engineering and Emerging Technologies, Montpellier, France.
authors.forename: Luis J
authors.initials: LJ
authors.lastname: López-Giraldo
authors.forename: Mickaël
authors.initials: M
authors.lastname: Laguerre
authors.forename: Jérome
authors.initials: J
authors.lastname: Lecomte
authors.forename: Maria-Cruz
authors.initials: MC
authors.lastname: Figueroa-Espinoza
authors.forename: Bruno
authors.initials: B
authors.lastname: Baréa
authors.forename: Jochen
authors.initials: J
authors.lastname: Weiss
authors.forename: Eric A
authors.initials: EA
authors.lastname: Decker
authors.forename: Pierre
authors.initials: P
authors.lastname: Villeneuve
mesh_terms: D001713:Biphenyl Compounds; D002726:Chlorogenic Acid / Q000737:chemistry* / Q000494:pharmacology; D002853:Chromatography, Liquid; D004952:Esters / Q000737:chemistry* / Q000494:pharmacology; D005233:Fatty Alcohols / Q000737:chemistry; D016166:Free Radical Scavengers / Q000494:pharmacology; D007700:Kinetics; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D010851:Picrates / Q000737:chemistry*; D013329:Structure-Activity Relationship
chemical_list: D001713:Biphenyl Compounds; D004952:Esters; D005233:Fatty Alcohols; D016166:Free Radical Scavengers; D010851:Picrates; D002726:Chlorogenic Acid; C004931:1,1-diphenyl-2-picrylhydrazyl