title: Photodegradation of hyaluronic acid: EPR and size exclusion chromatography study.
abstract: Photochemically induced radical reactions involving the lateral sequences and the end macromolecular chain groups of hyaluronic acid in aqueous solutions at 293K were studied by EPR spin trapping technique with DMPO (5,5-dimethylpyrroline-1-oxide). In the first 1-10 minutes of irradiation EPR indicates spin adducts of two carbon centered radicals with the splitting constants of aN = 1.60 mT, aH = 2.51 mT and aN = 1.56 mT, aH = 2.28 mT. After longer irradiation time (over 10 minutes) dominate two further DMPO adducts of radicals centered on hetero-atoms with splitting constants of aN = 1.44 mT, aH = 1.60 mT and of aN = 1.49 mT, aH = 1.49 mT. Simultaneously, molecular weight followed by SEC decreases, suggesting that UV irradiation leads to the breaking of interglycosidic bonds of hyaluronic acid main macromolecular chain.
authors.affiliation: Faculty of Chemical Technology, Slovak Technical University, Bratislava.
authors.forename: L
authors.initials: L
authors.lastname: Lapcík
authors.forename: P
authors.initials: P
authors.lastname: Chabrecek
authors.forename: A
authors.initials: A
authors.lastname: Stasko
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002850:Chromatography, Gel / Q000379:methods; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D006820:Hyaluronic Acid / Q000737:chemistry / Q000528:radiation effects*; D008969:Molecular Sequence Data; D010782:Photolysis; D013113:Spin Labels; D014466:Ultraviolet Rays
chemical_list: D003497:Cyclic N-Oxides; D013113:Spin Labels; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D006820:Hyaluronic Acid