Cancer-Preventive Effects of Drinking Green Tea among a Japanese Population

Imai, Kazue; Suga, Kenji; Nakachi, Kei

doi:10.1006/pmed.1997.0242

Cited by 312 publications

(170 citation statements)

References 23 publications

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“…Imai et al (30) reported that 28% of Japanese aged 60 years or over consumed 10 or more cups of green tea a day. They estimated that 10 cups of green tea would supply 300-400 mg of EGCG, assuming 150 mL of green tea per cup.…”

Section: Cyp Activity (% Of Control)mentioning

confidence: 99%

Inhibitory Effects of Eight Green Tea Catechins on Cytochrome P450 1A2, 2C9, 2D6, and 3A4 Activities

et al. 2016

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-PURPOSE:Green tea is a traditional beverage that has been enjoyed by the Japanese to this day. Recently, there has been an increase in the consumption of green tea beverage having high concentrations of catechins, such as (-)-epigallocatechin-3-O-gallate (EGCG). Many people tend to ingest large amounts of catechins through the frequent consumption of green tea beverage, and this dietary habit may lead to unwanted interactions between the catechins in green tea and medicinal drug. METHODS: The inhibitory effects of eight green tea catechins on drug metabolizing enzymes, cytochrome P450 (CYP) 1A2, 2C9, 2D6, and 3A4, were investigated in human liver microsomes. Incubation was initiated by the addition of cocktail probe drugs that served as specific substrates for each CYP, and the resulting metabolites were analyzed by LC-MS. RESULTS: From a comparison of the fifty percent inhibitory concentration (IC50) values of the eight green tea catechins, it was found that non-gallated catechins did not inhibit CYPs, whereas gallated catechins inhibited all CYPs except CYP2D6. Among them, CYP2C9 was most strongly inhibited by (-)-catechin-3-Ogallate (CG) (7.60 µM), and CYP1A2 was most strongly inhibited by EGCG (8.93 µM). Catechin gallate exhibited non-competitive inhibition of CYP2C9, and its Ki value was 9.76 ± 0.47µM. The present study is the first to report the inhibitory effect of CG on CYP2C9. In contrast, EGCG showed competitive inhibition of CYP1A2, and its Ki value was 14.3 ± 0.09 µM. CONCLUSION: Previous reports had predicted that plasma EGCG concentration reached 7.4 µM after ingesting green tea having high concentrations of catechins. That concentration of EGCG is equivalent to one-half to one-third of its Ki value for CYP1A2 and CYP3A4 in this study. The ingestion of beverages containing large amounts of green tea catechins together with drugs that are metabolized by CYP1A2, CYP2C9, and CYP3A4 should be avoided.

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Section: Cyp Activity (% Of Control)mentioning

confidence: 99%

Inhibitory Effects of Eight Green Tea Catechins on Cytochrome P450 1A2, 2C9, 2D6, and 3A4 Activities

et al. 2016

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“…Although animal studies have reported compelling results on the chemopreventive effects of green tea in lung cancer, human population-based studies have produced inconsistent findings. Some have found that green tea consumption is either associated with an increased 7 or reduced risk [8][9][10] of lung cancer, whereas others have found no effect. [11][12][13] In our previous studies, we have shown that GTE induces actin remodeling in transformed urothelial MC-T11 cells, antagonizes cigarette carcinogen 4-aminobiphenyl induced actin depolymerization in untransformed HUC-PC cells, and inhibits 4-aminobiphenyl induced motility in transformed MTC-11 cells using a unique in vitro bladder cancer carcinogenesis model.…”

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confidence: 99%

Green tea induces annexin-I expression in human lung adenocarcinoma A549 cells: involvement of annexin-I in actin remodeling

Jin

Zhang

et al. 2007

Laboratory Investigation

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Green tea polyphenols exhibit multiple antitumor activities in various in vitro and in vivo tumor models, and the mechanisms of action are not clear. Previously, we found that green tea extract (GTE) regulates actin remodeling in different cell culture systems. Actin remodeling plays an important role in cancer cell morphology, cell adhesion, motility, and invasion. Using proteomic approaches, we found GTE-induced expression of annexin-I, a multifunctional actin binding protein, in these cell lines. In this study, we aimed to further define the functional role of GTE-induced annexin-I expression in actin remodeling, cell adhesion, and motility in lung adenocarcinoma A549 cells. We found that GTE stimulates the expression of annexin-I in a dose-dependent fashion. The GTE-induced annexin-I expression appears to be at the transcription level, and the increased annexin-I expression mediates actin polymerization, resulting in enhanced cell adhesion and decreased motility. Annexin-I specific interference resulted in loss of GTE-induced actin polymerization and cell adhesion, but not motility. In fact, annexin-I specific interference itself inhibited motility even without GTE. Together, annexin-I plays an important role in GTE-induced actin remodeling, and it may serve as a potential molecular target associated with the anticancer activities of green tea.

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“…17,18) Other Japanese studies showed that consumption of green tea amounting to more than 10 cups per day lowered the incidence of cancers of the stomach, lung and other sites. [19][20][21] We previously reported that green tea polyphenols inhibit in vitro growth of ATL cells as well as HTLV-1-infected T-cells, by inducing apoptosis. 22) The present study was conducted to assess the in vivo effect of green tea to diminish HTLV-1 provirus load in peripheral blood lymphocytes of asymptomatic HTLV-1 carriers.…”

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confidence: 99%

HTLV‐1 provirus load in peripheral blood lymphocytes of HTLV‐1 carriers is diminished by green tea drinking

et al. 2004

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Cancer-Preventive Effects of Drinking Green Tea among a Japanese Population

Cited by 312 publications

References 23 publications

Inhibitory Effects of Eight Green Tea Catechins on Cytochrome P450 1A2, 2C9, 2D6, and 3A4 Activities

Inhibitory Effects of Eight Green Tea Catechins on Cytochrome P450 1A2, 2C9, 2D6, and 3A4 Activities

Green tea induces annexin-I expression in human lung adenocarcinoma A549 cells: involvement of annexin-I in actin remodeling

HTLV‐1 provirus load in peripheral blood lymphocytes of HTLV‐1 carriers is diminished by green tea drinking

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