title: Suppression of superoxide anion generation catalyzed by xanthine oxidase with alkyl caffeates and the scavenging activity.
abstract: Alkyl caffeates are strong antioxidants and inhibitors of xanthine oxidase. However, it is unclear about the effect of caffeic acid and alkyl caffeates on superoxide anion (O2(-)) generation catalyzed by xanthine oxidase. Effects of caffeic acid and alkyl caffeates on the uric acid formation and O2(-) generation catalyzed by xanthine oxidase were analyzed. The scavenging activities of 1,1-diphenyl-2-picryhydrazyl (DPPH) radical and O2(-) generated with phenazine methosulfate (PMS) and NADH were examined. Caffeic acid derivatives equally suppressed O2(-) generation, and the suppression is stronger than inhibition of xanthine oxidase. Scavenging activity of O2(-) is low compared to the suppression of O2(-) generation. Suppression of O2(-) generation catalyzed by xanthine oxidase with caffeic acid derivatives was not due to enzyme inhibition or O2(-) scavenging but due to the reduction of xanthine oxidase molecules. Alkyl caffeates are effective inhibitors of uric acid and O2(-) catalyzed by xanthine oxidase as well as antioxidants for edible oil.
authors.affiliation: a Department of Life Science , Okayama University of Science , Okayama , Japan ;
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Masuoka
authors.affiliation: b Department of Environmental Science, Policy and Management , University of California, Berkeley , Berkeley , CA , USA.
authors.forename: Isao
authors.initials: I
authors.lastname: Kubo
mesh_terms: D002109:Caffeic Acids / Q000737:chemistry*; D016166:Free Radical Scavengers; D015394:Molecular Structure; D017382:Reactive Oxygen Species; D013481:Superoxides / Q000737:chemistry / Q000378:metabolism*; D014527:Uric Acid / Q000737:chemistry / Q000378:metabolism; D014969:Xanthine Oxidase / Q000737:chemistry / Q000378:metabolism*
chemical_list: D002109:Caffeic Acids; D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D013481:Superoxides; D014527:Uric Acid; D014969:Xanthine Oxidase; C040048:caffeic acid
keywords: Caffeic acid; enzyme inhibition; enzyme reduction; phenazine methosulfate-NADH