title: DPPH radical scavenging reaction of hydroxy- and methoxychalcones.
abstract: The DPPH radical scavenging activity of 2',4',6'-trihydroxy- and 2'-hydroxy-4',6'-dimethoxychalcones carrying a 2,3- and 3,4-dihydroxylated, and 3,4,5-trihydroxylated B-ring was evaluated in alcoholic and non-alcoholic solvents. All test compounds scavenged more than two equivalent of radicals by a possible conversion to the corresponding B-ring quinones and in most cases subsequently underwent cyclization to aurones and flavanones, these being identified in the reaction solutions by an in situ NMR analysis. Interestingly, the reaction between 2',3,4-trihydroxy-4',6'-dimethoxychalcone and the DPPH radical was significantly affected by the solvent used, which might be accounted for by the difference in readiness for cyclization to an aurone.
authors.affiliation: Laboratory of Food Biochemistry, Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapparo, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Nishida
authors.forename: Jun
authors.initials: J
authors.lastname: Kawabata
mesh_terms: D001713:Biphenyl Compounds; D002599:Chalcone / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry*; D006900:Hydroxylation; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010851:Picrates / Q000737:chemistry*
chemical_list: D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D010851:Picrates; D002599:Chalcone; C004931:1,1-diphenyl-2-picrylhydrazyl