Kinetic analysis of the effect of (-)-epigallocatechin gallate on the DNA scission induced by Fe(II).
The DNA strand scission induced by Fe(II) in a citrate buffer solution and the effect of (-)-epigallocatechin gallate (EGCg) were kinetically analyzed. The rate of consumption of dissolved oxygen by Fe(II) in each of these solutions was measured and paralleled that DNA scission. Coordinated EGCg accelerated these reactions. Curves of the time-course characteristics of DNA scission were simulated by using the rate constant of oxygen consumption and by assuming that scission with the hydroxyl radical (OH), which was formed from the dissolved oxygen, proceeded competitively with the scavenging of OH by citrate, Cl- ions and EGCg added. Free EGCg acted as a DNA scission inhibitor to scavenge OH, in contrast to the case of the coordinated one. This analysis is useful for estimating the rate constant of the reaction between an antioxidant and OH, and might provide a new method for measuring the OH-scavenging activity.
Ohashi
Yasunori
Y
Radiochemistry Research Laboratory, Shizuoka University, Shizuoka-shi, Japan.
Yoshinaga
Koichi
K
Yoshioka
Hisashi
H
Yoshioka
Hiroe
H
D016587:Antimutagenic Agents / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D019343:Citric Acid; D004269:DNA, Bacterial / Q000737:chemistry* / Q000187:drug effects; D004926:Escherichia coli; D005296:Ferrous Compounds / Q000494:pharmacology*; D007700:Kinetics; D009690:Nucleic Acid Conformation / Q000187:drug effects; D010957:Plasmids / Q000737:chemistry* / Q000187:drug effects
D016587:Antimutagenic Agents; D004269:DNA, Bacterial; D005296:Ferrous Compounds; D019343:Citric Acid; C016600:ferrous citrate; D002392:Catechin; C045651:epigallocatechin gallate