Cancer Prevention with Green Tea Polyphenols for the General Population, and for Patients Following Cancer Treatment

Current Cancer Therapy Reviews, 2005, 1, 109-114
109
Cancer Prevention with Green Tea Polyphenols for the General Population,
and for Patients Following Cancer Treatment
Hirota Fujiki*,1, Masami Suganuma2, Satoru Matsuyama3 and Kohji Miyazaki3
1Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Japan
2Saitama Cancer Center, Japan
3Department of Surgery, Saga University, Japan
Abstract: Green tea is now known to be the most effective beverage for cancer prevention, and evidence of this
was recently extended to clinical applications. This paper briefly reviews several topics with regard to the
development of our study on cancer prevention with green tea, and proposes a strategy for two-stages of cancer
prevention with green tea. The topics are : 1) introduction of our initial work on (-)-epigallocatechin gallate
(EGCG), the main constituent of Japanese green tea; 2) cancer preventive effects of EGCG and green tea extract,
the lyophilized form of green tea infusion; 3) bioavailability of 3H-EGCG in mice; 4) delay of cancer onset by
drinking 10 Japanese-size cups of green tea per day; 5) a prototype study for developing green tea beverage
supplemented with green tea tablets by 102 healthy volunteers; 6) cancer prevention before cancer onset for
the general population and high risk groups; 7) cancer prevention for patients following cancer treatment; 8)
an example of a clinical trial looking toward prevention of cancer recurrence in the liver; and 9) possible
prevention of human lung cancer. Considering all the above, green tea is a multi-, non-toxic cancer preventive
for humans: It is nature’s remedy.
Keywords: Green tea, EGCG, 10 Japanese-size cups, general population, cancer patients.
INTRODUCTION
CANCER PREVENTIVE EFFECTS OF EGCG AND
GREEN TEA EXTRACT
In 1983 we did the first scientific examination of (-)-
epigallocatechin gallate (EGCG), the main constituent of
EGCG and green tea extract have demonstrated the
green tea and green tea extract, the lyophilized form of green
following attributes as cancer preventives: They are non-
tea infusion (Fig. 1). We studied their potential as cancer
toxic, for rodents and humans; they have a wide-range of
preventives in collaboration with Takuo Okuda, who was
target organs, such as digestive tract including esophagus,
Professor of Faculty of Pharmaceutical Sciences at Okayama
stomach, duodenum and colon, plus lung, liver, pancreas,
University at that time. EGCG inhibited both the phorbol
breast, bladder, prostate, and skin; they have inhibitory
ester receptor binding with a tumor promoter, 12-O-
effects on growth of human cancer cells associated with
tetradecanoylphorbol-13-acetate (TPA), in a membrane
G2/M arrest in PC-9 cells; and they showed inhibitory
fraction of mouse skin, and activation of protein kinase C by
effects on lung metastasis of B16 melanoma cells, associated
the tumor promoter. The results suggested that EGCG acted
with reduction of various cytokine levels [4].
as antagonist, inhibiting the action of tumor promoters. In
To look at the mechanisms of action of green tea
1987, we first reported that topical applications of EGCG
polyphenols in cancer prevention, it is worthwhile to discuss
inhibited tumor promotion of teleocidin, a TPA-type tumor
evidence on TNF-?, the endogenous tumor promoter. We
promoter in a two-stage carcinogenesis experiment on mouse
have obtained results showing that numerous inhibitors of
skin [1]. In addition, EGCG completely inhibited tumor
tumor promotion and cancer preventive agents inhibited both
promotion of okadaic acid, which is as potent as TPA,
TNF-? gene expression in the cells and TNF-? release from
mediated through inhibition of protein phosphatases 1 and
the cells induced by tumor promoters, resulting in a
2A [2]. Since EGCG inhibited both PKC pathway and
reduction of the amount of TNF-? in cancer cells and
okadaic acid pathway, we thought that EGCG treatment
probably in their surrounding tissues [5]: The tea
possibly inhibited the interaction of tumor promoters with
polyphenols (-)-epicatechin gallate (ECG), EGCG and (-)-
their receptors: We named this the sealing effect [2]. The
epigallocatechin (EGC) dose-dependently inhibited TNF-?
results encouraged us to move on to a significant project,
release from a human stomach cancer cell line, KATO III
cancer prevention with green tea, based on the fact that
cells, treated with okadaic acid. The potency of these green
Japanese drink green tea all day long [3].
tea polyphenols is closely associated with the potency of
their growth inhibition [5].
Green tea extract contains at least four tea polyphenols:
EGCG, ECG and EGC are active compounds, while (-)-
*Address correspondence to this author at the Department of
epicatechin (EC) is inactive (Fig. 1). However, cotreatment
Biochemistry, Faculty of Pharmaceutical Sciences, Tokushima Bunri
with EC and EGCG, and EC and other tea polyphenols,
University, Yamashiro-cho, Tokushima 770-8514, Japan; Tel: 81-88-622-
synergistically enhanced cancer preventive activity such as
9611 Ext. 5811; Fax: 81-88-655-3051; E-mail: hfujiki@ph.bunri-u.ac.jp
induction of apoptosis and inhibition of TNF-? release [5]
1573-3947/05 $50.00+.00
© 2005 Bentham Science Publishers Ltd.

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110 Current Cancer Therapy Reviews, 2005, Vol. 1, No. 1
Fujiki et al.
OH
OH
O H
OH
OH
OH
O H
HO
O
HO
O
HO
O
OH
OH
OH
O
HO
O
OH
O
OH
C
OH
OH
C
OH
OH
O
O
OH
OH
OH
OH
OH
O H
EGCG
ECG
EGC
EC
Fig. (1). Structures of (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epicatechin
(EC).
(Table 1). These results strongly indicate that whole green
green tea extract had previously been shown to inhibit
tea is a more efficient mixture of tea polyphenols for human
carcinogenesis (Table 2).
cancer prevention than EGCG alone.
DELAY OF CANCER ONSET BY DRINKING 10
BIOAVAILABILITY OF 3H-EGCG IN MICE
JAPANESE-SIZE CUPS OF GREEN TEA PER DAY
From the systemic effects of EGCG and green tea extract,
Green tea beverage as a cancer preventive has numerous
we assumed that EGCG and green tea polyphenols were
advantages, and one scientific advantage is that results on
easily distributed from the digestive tract to various organs
the cancer preventive effects of green tea can be obtained
where they induced anticarcinogenic effects. To prove this,
from prospective cohort studies with humans consuming
we obtained 3H-EGCG with a specific activity of 48.1
green tea. Kazue Imai and Kei Nakachi surveyed 8,552
GBq/mmol - fortunately a very stable compound. Whether
individuals aged over 40 in Saitama Prefecture, Japan, in
3H-EGCG could be incorporated into human lung cancer cell
1986, on their living habits, including daily consumption of
line PC-9 cells was first studied in the culture, and after
green tea. During the 10 years after 1986, they found a total
treatment with 3H-EGCG for 1 and 24 hours, PC-9 cells
of 419 cancer patients, 175 females and 244 males, among
were subjected to microautoradiography: Silver grains of 3H-
participants in the cohort study. Their study (1986 – 1996)
EGCG appeared in the membrane, cytosol and nuclei,
revealed that drinking 10 Japanese-size cups (120 ml/cup) of
seeming to confirm that EGCG is incorporated into cancer
green tea per day delayed cancer onset in humans by 7.3
cells [6]. We next administered 3H-EGCG into mouse
years among females and by 3.2 years among males,
stomach and studied its distribution: Within 24 hours after
compared with patients who had consumed less than three
administration, 6.6% of total administered radioactivity was
cups per day [8] (Table 3). The difference between females
excreted in urine and 37.7% in feces. In addition, various
and males is partly due to higher tobacco consumption by
amounts of the total administered radioactivity were found
males, but the results clearly indicated that drinking the
24 hours after intubation in the digestive tract, liver, brain,
equivalent of 10 Japanese-size cups per day, about 2.5 g
kidney, lung, pancreas, and skin [7] (Table 2). Thus, the
green tea extract, prevents cancer in the general population.
radioactivity was present in the organs where EGCG and
Furthermore, the reduction of relative risk of cancers was
Table 1.
Synergistic Effects by Cotreatment with EC and Other Tea Polyphenols on Apoptosis and Growth Inhibition of Human
Lung Cancer Cell Line PC-9, and on Inhibition of TNF-? Release from BALB/3T3 Cells
Induction of apoptosisa (A415 nm)
Growth inhibitionb (% of control)
Inhibition of TNF-? releaseb IC50 (µM)
without EC
with EC (200 µM)
without EC
with EC (200 µM)
without EC
with EC (100 µM)
0.10 + 0.03
97.8
>500c
EGCG (100 µMd)
0.52 + 0.22
0.98 + 0.28
73.3
27.8
60
1e
ECG (50 µMd)
0.27 + 0.13
0.53 + 0.18
62.2
43.3
30
7
EGC (200 µMd)
0.14 + 0.03
0.43 + 0.08e
100.0
72.2
n.d.
n.d.
aValues represent the mean + SD of two separate experiments performed in duplicate.
bValues are representative of two separate experiments performed in duplicate.
cIC50 of EC
dConcentration for experiment on apoptosis and growth inhibition of human lung cancer cell line PC-9.
eP<0.01.

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Green Tea Beverage as a Cancer Preventive
Current Cancer Therapy Reviews, 2005, Vol. 1, No. 1 111
achieved by high consumption of green tea in all organs,
questionnaires, and their blood samples were examined. We
such as lung, colorectum, liver and stomach [8].
obtained the following answers from the questionnaires:
93% of the participants were able to continue drinking green
Table 2.
Incorporation of 3H-EGCG into Target Organs and Associated with Reduction of Tumor Incidence
Organs
% of total administered
% of tumor-bearing animals
radioactivity (24 h after)
without with EGCG
Stomach
3.93
62.2 ? 31.0
Duodenum
0.35
63.0 ? 20.2
Small intestine
5.69
n.d.
Colon
4.52
77.3 ? 38.1
67.0 ? 33.0*
Liver
0.89
83.3 ? 53.2
Brain
0.32
n.d.
Kidney
0.28
n.d.
Lung
0.16
96.3 ? 65.5
Pancreas
0.07
54.0 ? 28.0
Skin
1.9 x 104/100 mg
65.0 ? 28.0*
*: Green tea extract
n.d.: Not determined
A PROTOTYPE STUDY FOR DEVELOPING GREEN
tea and taking green tea tablets, and over 90% of the
TEA BEVERAGE SUPPLEMENTED WITH GREEN
participants found their living habits or meals unaffected by
TEA TABLETS BY 102 HEALTHY VOLUNTEERS
green tea. Our conclusion is that most Japanese can easily
take the recommended 10 cups of green tea per day, or 2.5 g
We have determined that the effective cancer preventive
green tea extract per day [11].
amount is 10 Japanese-size cups of green tea per day, based
Table 3.
Age of Cancer Onset According to Green Tea
on both the results of the cohort study mentioned above [8],
Consumption
and the results of a case control study on gastric cancer and
diet by Kono’s group, conducted in southern Japan in 1988
[9]. One Japanese-size cup contains roughly 80 – 120 ml,
Green tea consumption (cups/day)
and 10 cups contain about 2.5 g green tea extract. We now
< 3
4 - 9
> 10
recommend taking this amount daily using a combination of
green tea beverage and tablets of green tea extract [10].
Females
67.0 + 1.7
66.4 + 1.3
74.3 + 2.2
Before going on to clinical study, we asked some 100
(175)a
(49)
(102)
(24)
healthy volunteers to consume daily 10 Japanese-size cups of
Males
65.0 + 1.5
67.2 + 1.0
68.2 + 1.1
green tea for three months, with informed consent. Group A
of 51 volunteers took green tea beverage and green tea tablets
(244)
(59)
(114)
(71)
for the first 3 months, and group B, the same number, took
aNumber of cancer cases
green tea beverage and the tablets for another 3 months.
About 50% of the volunteers experienced very mild
After six months trial, all 102 volunteers answered
temporary disorders, such as abdominal bloating, heartburn,
Fig. (2). Two-stages of cancer prevention with green tea: for the general population before cancer onset and for patients following
cancer treatment.

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112 Current Cancer Therapy Reviews, 2005, Vol. 1, No. 1
Fujiki et al.
Fig. (3). Prevention of cancer recurrence in the liver at a University clinic.
nausea, and insomnia, due to the caffeine in green tea
Japanese clinicians, we are making progress toward
extract. Since we thought that tablets containing 5% caffeine
prevention of cancer recurrence in various organs, including
might have caused some disorders, the caffeine content was
relapse of prostate cancer, polyp development after colorectal
reduced from 5% to less than 3% [11]. We chose not to
polypectomy, and recurrence of breast, liver and esophagus
make completely decaffeinated tea, since Conney’s group
cancers [10, 11]. We call cancer prevention for both the
had demonstrated that decaffeinated teas were inactive or less
general population and cancer patients “The two-stages of
effective inhibitors of tumor formation [12]. New green tea
cancer prevention with green tea” (Fig. 2) [13].
tablets containing less than 3% caffeine recently went on sale
Recently we obtained some exciting results on preve-
in Japan, under the commercial name of G.T.E. and
ntion of polyp development after colorectal polypectomy, by
produced by Iruma-Kumiai Seicha in Saitama Prefecture
consuming 10 Japanese-size cups of green tea supplemented
[11]. These tablets now make it possible for both the general
with green tea tablets (Moriwaki, personal communication).
population and high risk groups to easily consume the
recommended amount of green tea polyphenols. We call this
The First stage of cancer prevention with green tea, leading
AN EXAMPLE OF A CLINICAL TRIAL
to delay of cancer onset, as our cohort study already
indicated [13] (Fig. 2).
A study on prevention of cancer recurrence in the liver
was conducted at a Japanese University clinic (Fig. 3). First,
after liver cancer patients had cancer lesions removed, they
CANCER PREVENTION FOR PATIENTS FOLLO-
listened to an explanation of clinical trials with green tea
WING CANCER TREATMENT
supplemented with green tea tablets. Patients who chose to
join the trials agreed by informed consent and were divided
Due to advances in diagnosis and treatment of cancers,
into two groups: those drinking 10 cups of green tea
there are many healthy cancer patients in Japan. Specifically,
supplemented with green tea tablets for one year or drinking
there are 2.7 million surviving cancer patients, and 1.6
just the usual amount (less than 10 cups). During the year,
million have survived over 5 years. These patients are
they were given physical checkups and blood tests every
seriously looking for drugs that will prevent recurrence,
three months, and at the end of the year, they answered a
second primary tumors and metastasis. In collaboration with
Fig. (4). Structures of heterogeneous nuclear ribonucleoprotein A2 (hnRNP A2) and hnRNP B1 proteins.

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Green Tea Beverage as a Cancer Preventive
Current Cancer Therapy Reviews, 2005, Vol. 1, No. 1 113
Table 4.
Inhibition of A549 Cell Growth and hnRNP B1 Gene Expression by EGCG, ECG or Genistein
Inhibition of cell
Inhibition of hnRNP B1 gene expression
growth IC50 (µM)
mRNA expression IC50 (µM)
Transcriptional regulation IC50 (µM)
EGCG
70.0
25.0
29.0
ECG
60.0
50.0
n.d.
Genistein
27.0
36.0
66.0
n.d.: Not determined
questionnaire. At present, 15 patients are drinking 10 cups
inhibited both transcriptional regulation of hnRNP A2/B1
of green tea supplemented with green tea tablets, and do not
gene and production of hnRNP B1 protein in human lung
complain any adverse effects, while 10 patients drink usual
cancer cell lines (Table 4). Thus, lung is a reasonable and
amounts of green tea without the supplements. Results are
efficient target organ for human cancer prevention with green
encouraging.
tea, using monitoring by a new specific biomarker, hnRNP
B1.
POSSIBLE PREVENTION OF HUMAN LUNG
CANCER
CONCLUSION
Lung cancer prevention is a worthy challenge for green
Since we established green tea beverage as cancer
tea, since large-scale lung cancer chemoprevention trials with
preventive, we have proposed our definition of cancer
various compounds have been unable to demonstrate any
prevention as follows: the administration of cancer
preventive effects on lung cancer in humans [14, 15]. It has
preventives, such as green tea, to delay the carcinogenic
already been reported that tobacco-specific nitrosamine-
process in humans - no matter when the carcinogenesis starts
induced lung tumorigenesis in A/J mice was inhibited by
- thereby blocking the appearance of clinical symptoms.
green tea [16], and green tea consumption in Japan may be
responsible, in part, for the lower cancer mortality rate
among Japanese cigarette smokers [17]. As previously
ACKNOWLEDGEMENTS
reported, radioactivity of 3H-EGCG was distributed into the
lungs, and silver grains derived from 3H-EGCG, as
This work was supported by Scientific Research on
determined by microautoradiography, were found in the cells
Priority Areas for Cancer Research from the Ministry of
of the lungs, clearly indicating that the lungs are target
Education, Culture, Sports, Science, and Technology, Japan:
organs [7]. In addition, we have demonstrated that duplicate
Encouragement of Young Scientists from Japan Society for
administrations of 3H-EGCG at 6 hour intervals enhanced
the Promotion of Science of Japan: Comprehensive Research
incorporation of the radioactivity in the lungs 4 times. All
on Aging and Health, and Cancer Research from the
the results show that the more green tea we drink, the higher
Ministry of Health, Labor, and Welfare, Japan: Selectively
concentrations of green tea polyphenols we get in the lungs
Applied and Developed Research, and Green Tea Extracts
[7].
Research Development for Cancer Prevention by the
Department of Agriculture and Forest and the Department of
To achieve successful cancer prevention in the lungs, we
Health and Human Services from Saitama Prefecture of
have to establish a significant biomarker for lung cancer
Japan: and Smoking Research Fund. We thank Profs. Takuo
prevention in humans. In 1988, Melvyn S. Tockman and
Okuda and Takashi Yoshida for their stimulating
James L. Mulshine first identified heterogeneous nuclear
collaboration, and Mr. Yoshiaki Kitaoka and Mr. Kenta
ribonucleoprotein A2/B1 (hnRNP A2/B1) protein as an early
Nakajima for their fruitful discussion.
biomarker of human lung cancer [18]. Although hnRNP
A2/B1 protein was intriguing, its antibody seemed unable to
well differentiate lung cancer cells from normal lung cells.
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