(+)-Catechin, an ingredient of green tea, protects murine microglia from oxidative stress-induced DNA damage and cell cycle arrest.
Extracts of Chinese herbs have been demonstrated to inhibit oxidative stress in vitro. In this study, we investigated the mechanism of (+)-catechin, isolated from green tea, which preserved murine microglia N9 cells from an oxidative agent tert-butylhydroperoxide (tBHP)-induced cell death. (+)-Catechin augmented the cell survival ratio after exposure to tBHP. Protective action of this drug was more efficacious than that of N-acetylcysteine, which is a putative antioxidant. DNA damage, detected by the Comet assay, was diminished with treatment of the drug. Results of flow cytometric analysis showed that the amount of intracellular *OH was decreased, and the cell cycle arrest was reversed by down-regulation of p53 phosphorylation after treatment with (+)-catechin. The reduced p53 activity followed the impairment of NF-kappaB translocation to the nuclear region. Then the phosphorylation of extracellular signal regulated protein kinase, a cell survival facilitative signal, was upregulated at the later stage. Taken together, (+)-catechin inhibited tBHP-induced translocation of NF-kappaB to improve cellular survival.
Huang
Qing
Q
China-Japan Research Institute of Medical and Pharmaceutical Sciences, Shenyang Pharmaceutical University, Shenyang 110016, China.
Wu
Li-Jun
LJ
Tashiro
Shin-ichi
S
Gao
Hui-Yuan
HY
Onodera
Satoshi
S
Ikejima
Takashi
T
D000818:Animals; D028244:Camellia; D002392:Catechin / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects* / Q000502:physiology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D004249:DNA Damage / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D051379:Mice; D017628:Microglia / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D013662:Tea
D013662:Tea; D002392:Catechin