Epidemiological and experimental studies on the antitumor activity by green tea extracts.

Oguni, Itaro; Nasu, Keiko; Kanaya, Setsuko; Ota, Yuichi; Yamamoto, Shigehiro; Nomura, Takeo

doi:10.5264/eiyogakuzashi.47.93

Cited by 58 publications

(15 citation statements)

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“…The standardized mortality rate for cancer of all sites in the midwest area of this prefecture, where green tea is a staple, is even lower. 7 In a recent case-control epidemiological study of urinary bladder cancer in metropolitan Nagoya, green tea and fruit juice intake was suggested to protect against the development of bladder cancer. 8 No confirmation of an effect of green tea against vesical oncogenesis has been reported.…”

Section: Introductionmentioning

confidence: 99%

Inhibition of urinary bladder tumors induced by N‐butyl‐N‐(4‐hydroxybutyl)‐nitrosamine in rats by green tea

Sato

1999

Int J of Urology

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Background: Recently, the anticarcinogenic effects of green tea have been studied in sites other than the urinary tract. The present study examined the inhibition by green tea of vesical tumors induced in rats by Nbutyl-N-(4-hydroxybutyl) nitrosamine (BBN). Methods:In the first series of experiments, 0.05% BBN was added to the drinking water of rats and remained present for 5 weeks. In one experiment, six groups of animals received either tap water, green tea, matcha, hojicha, oolong tea or black tea from week 6. In a second experiment, three groups of rats received either tap water, green tea extract or powdered green tea mixed into a pellet diet from week 6. In a third experiment, five groups of rats were fed a pellet diet with addition of either 0, 0.15, 1.5 or 3.0% powdered green tea from week 6. All rats were killed and examined at 40 weeks. Results: Green tea, particularly green tea leaves, dose-dependently inhibited the growth of BBN-induced urinary bladder tumors when given after the carcinogen. Conclusions: Green tea may inhibit bladder tumor growth.

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Section: Introductionmentioning

confidence: 99%

Inhibition of urinary bladder tumors induced by N‐butyl‐N‐(4‐hydroxybutyl)‐nitrosamine in rats by green tea

Sato

1999

Int J of Urology

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“…15) There are some epidemiological reports that the consumption of green tea infusion reduced the risk of gastric cancer in case-control studies. [16][17][18][19][20][21] In contrast, some researchers reported that the consumption of green tea was not associated with the reduction of gastric cancer using recent prospective studies. [22][23][24][25] In these reports that described the inhibitory effects or non-effects of green tea against cancer death, the relationship between the numbers of cups of green tea consumed and cancer death was examined, but the concentrations of catechins in the brewed tea infusion were not determined.…”

Section: Effect Of Green Tea On the Formation Of Nitrosamines And Camentioning

confidence: 99%

Effect of Green Tea on the Formation of Nitrosamines, and Cancer Mortality

Masuda

Uchida

Terashima

et al. 2006

JOURNAL OF HEALTH SCIENCE

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“…It has been proposed that compounds that inhibit such communication may function as tumour promoters by interfering with cell-cell growth regulatory mechanisms and thereby encouraging cellular replication (Trosko & Chang, 1984). Epidemiological evidence suggests that green tea may be protective against cancer (Oguni et al 1989). An extract of green tea consisting largely of various catechins (Maeda & Nakagawa, 1977) previously shown to possess antimutagenic and anticarcinogenic properties (Cheng et al 1986;Ruch et al 1989) apparently prevents the inhibition of intercellular communication induced in cultured mammalian cells by the promoters phenobarbital and 12-O-tetradecanoylphorbol-13-acetate (Ruch et al 1989).…”

Section: Modification Of Intracelluiar Signallingmentioning

confidence: 99%