title: Caffeoylquinic acid derived free radicals identified during antioxidant reactions of bitter tea (Ilex latifolia and Ilex kudincha).
abstract: In order to provide some insight into the chemical basis for the antioxidant behaviour of bitter tea, the Chinese medicinal beverage derived from leaves of Ilex kudincha or Ilex latifolia, free radicals generated during the oxidation of aqueous extracts of dried leaves have been investigated by electron paramagnetic resonance (EPR) spectroscopy. With both beverages, the major components in the EPR spectra after accelerated autoxidation under alkaline conditions or oxidation with the superoxide anion radical were comparable to those derived from reactions of caffeoylquinic acids. Thus these reaction products have sufficient stability for biological activity, and the present results suggest that such molecules contribute appreciably to the antioxidant chemistry of these beverages.
authors.affiliation: Health and Environment Department, Environmental Resources & Technologies, Austrian Institute of Technology, A-2444 Seibersdorf, Austria. katharina.pirker@ait.ac.at
authors.forename: Katharina Franziska
authors.initials: KF
authors.lastname: Pirker
authors.forename: Bernard Albert
authors.initials: BA
authors.lastname: Goodman
mesh_terms: D000975:Antioxidants / Q000737:chemistry* / Q000378:metabolism; D001628:Beverages / Q000032:analysis*; D002726:Chlorogenic Acid / Q000737:chemistry / Q000378:metabolism; D002934:Cinnamates / Q000737:chemistry / Q000378:metabolism; D004365:Drugs, Chinese Herbal / Q000737:chemistry* / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D030017:Ilex / Q000737:chemistry*; D010084:Oxidation-Reduction; D018515:Plant Leaves / Q000737:chemistry; D011801:Quinic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D013481:Superoxides / Q000737:chemistry / Q000378:metabolism
chemical_list: D000975:Antioxidants; D002934:Cinnamates; D004365:Drugs, Chinese Herbal; D005609:Free Radicals; C472707:caffeoylquinic acid; D011801:Quinic Acid; D013481:Superoxides; D002726:Chlorogenic Acid; C100257:cynarine