Role of hydrogen peroxide in bactericidal action of catechin.
Catechin (epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC) and epigallocatechin gallate (EGCg)), which occur in green tea and black tea, possess strong bactericidal action. We observed a reactive oxygen species that was generated from the catechins as the active mechanism: and this reactive oxygen was identified. EGCg reacted with the dissolved oxygen in aqueous solution, resulting in the generation of hydrogen peroxide. Hydrogen peroxide production derived from EGCg rose with increasing pH. EGCg (0.22 mmol/l) in neutral solution (0.1 mol/l phosphate buffer pH 7.0: PBS) quantitatively generated 0.2 mmol/l hydrogen peroxide after 60 min incubation. The bactericidal effect of EGCg is dependent on hydrogen peroxide levels produced by EGCg; moreover, EGCg action was inhibited by treatment with catalase. Both bactericidal effects correlated closely when the effects of EGCg and hydrogen peroxide for the bacterium (9 of 10 kinds of bacterial strains) were examined. Therefore, hydrogen peroxide, which is generated by EGCg, appears to be involved in the bactericidal action of EGCg.
School of Pharmaceutical Sciences, Department of Analytical Chemistry, Showa University, Tokyo, Japan. arakawa@pharm.showa-u.ac.jp
Hidetoshi
H
Arakawa
Masako
M
Maeda
Sachie
S
Okubo
Tadakatsu
T
Shimamura
D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000494:pharmacology; D006088:Gram-Negative Aerobic Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D016877:Oxidants / Q000737:chemistry*; D013662:Tea / Q000737:chemistry; D013997:Time Factors
D000900:Anti-Bacterial Agents; D016877:Oxidants; D013662:Tea; D002392:Catechin; C062669:epicatechin gallate; D006861:Hydrogen Peroxide; C045651:epigallocatechin gallate