title: Studies on the 1,1-diphenyl-2-picrylhydrazyl radical scavenging mechanism for a 2-pyrone compound.
abstract: The radical scavenging mechanisms for the 2-pyrone compound, 4-hydroxy-3,6-dimethyl-2H-pyrane-2-one (1), and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical (4) in several solvent systems were evaluated by the quantitative change in compounds detected at 270 nm and subsequent HPLC analyses. The HPLC profile for each condition suggested that the reaction proceeded by a different mechanism in each solvent system. In organic solvents (CHCl3, iso-propanol, and EtOH), 1-[4-(3,4-dihydro-3,6-dimethyl-2,4-dioxo-2H-pyran-3-yl) phenyl]-1-phenyl-2-picrylhydrazine (2) was produced as an adduct of the DPPH radical and 1. On the other hand, the reaction in a buffer solution (an acetate buffer at pH 5.5) gave several degradation products with 1[4-(2,3-dihydro-2,5-dimethyl-3-oxo-fur-2-yl) phenyl]-1-phenyl-2-picrylhydrazine (5), this being structurally elucidated by spectroscopic analyses. The decrease of the DPPH radical in each reaction system suggests that compound 1 could scavenge about 1.5-1.8 equivalents of the radical in organic solvents and about 3.5-3.9 in the buffer solution.
authors.affiliation: Laboratory of Applied Microbiology, School of Food and Nutritional Sciences, University of Shizuoka, Japan. abe@fns1.u-shizuoka-jen.ac.jp
authors.forename: N
authors.initials: N
authors.lastname: Abe
authors.forename: A
authors.initials: A
authors.lastname: Nemoto
authors.forename: Y
authors.initials: Y
authors.lastname: Tsuchiya
authors.forename: H
authors.initials: H
authors.lastname: Hojo
authors.forename: A
authors.initials: A
authors.lastname: Hirota
mesh_terms: D015764:Bepridil / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology*; D007700:Kinetics; D015394:Molecular Structure; D010851:Picrates; D011753:Pyrones / Q000737:chemistry / Q000494:pharmacology*; D013057:Spectrum Analysis
chemical_list: D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D010851:Picrates; D011753:Pyrones; C089682:4-hydroxy-3,6-dimethyl-2H-pyran-2-one; D015764:Bepridil; C004931:1,1-diphenyl-2-picrylhydrazyl