title: Prooxidative activities of tea catechins in the presence of Cu2+.
abstract: The ability of various tea catechins to generate H2O2 and the hydroxyl radical in the presence of the Cu2+ ion was investigated and compared with the effect of iron ions. The presence of Cu2+ accelerated the generation of H2O2 by EGC, while EGCg with Cu2+ generated a little H2O2. The presence of iron ions inhibited the generation of H2O2 by EGC. EGC and EC with Cu2+ generated the hydroxyl radical, while EGCg and ECg with Cu2+ did not. The fact that EGCg showed less prooxidative activity than EGC can be explained by the chelating ability of catechin gallates to metal ions under the experimental conditions.
authors.affiliation: School of Human Cultures, The University of Shiga Prefecture, Hassaka-cho, Hikone, Japan.
authors.forename: Fumiko
authors.initials: F
authors.lastname: Hayakawa
authors.forename: Yoko
authors.initials: Y
authors.lastname: Ishizu
authors.forename: Nobuo
authors.initials: N
authors.lastname: Hoshino
authors.forename: Akira
authors.initials: A
authors.lastname: Yamaji
authors.forename: Takashi
authors.initials: T
authors.lastname: Ando
authors.forename: Takahide
authors.initials: T
authors.lastname: Kimura
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry*; D003300:Copper / Q000737:chemistry / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000737:chemistry; D007501:Iron / Q000737:chemistry / Q000494:pharmacology; D010084:Oxidation-Reduction; D013662:Tea / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D013662:Tea; D003300:Copper; D002392:Catechin; C062669:epicatechin gallate; D006861:Hydrogen Peroxide; C045651:epigallocatechin gallate; D007501:Iron; C057580:gallocatechol