Suppression of cytotoxin-induced cell death in isolated hepatocytes by tea catechins.
To elucidate the hepatoprotective effects of green tea catechins, the following experiments were conducted utilizing (-)-epigallocatechin-3-gallate (EGCG), the major component of green tea catechin, together with other catechins. The protective effects of catechins against hepatotoxins, bromobenzene or rubratoxin B, were examined in primary cultures of rat hepatocytes. Bromobenzene and rubratoxin B are known to induce necrosis and apoptosis of cells, respectively. After 24-h treatment with toxin, EGCG and (-)-epigallocatechin-3-(3"-O-methyl)gallate (EGCg-3"-OMe) suppressed the bromobenzene-induced morphological change and dose-dependently prevented bromobenzene-induced cell death. Both catechins also prevented apoptotic cell death caused by rubratoxin B. In rubratoxin B-treated cells, both catechins were found to suppress the activation of caspase-3 by rubratoxin B. The results in the present study suggest that EGCG and EGCg-3"-OMe are potent hepatoprotective agents. This report is the first to show that catechins suppress cytotoxin-induced cell death.
Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan.
Noritaka
N
Kagaya
Yoh-ichi
Y
Tagawa
Hitoshi
H
Nagashima
Ryoyasu
R
Saijo
Masaya
M
Kawase
Kiyohito
K
Yagi
D000818:Animals; D001969:Bromobenzenes / Q000633:toxicity*; D053148:Caspase 3; D020169:Caspases / Q000096:biosynthesis; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004790:Enzyme Induction; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009183:Mycotoxins / Q000633:toxicity*; D020011:Protective Agents / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013662:Tea
D001969:Bromobenzenes; D009183:Mycotoxins; D020011:Protective Agents; D013662:Tea; C420224:epigallocatechin-3-(3''-O-methyl)gallate; C100297:rubratoxins; D002392:Catechin; C045651:epigallocatechin gallate; C032036:bromobenzene; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases