Green tea catechins for well-being and therapy: prospects and opportunities

Figures & data

Figure 1 Chemical structures of (+)-catechin and four major green tea catechins.

Figure 2 Effects of EGCG on gene expression of G6Pase, PEPCK, and HNF4α.¹⁸

Notes: Gene expression is expressed as a relative value to that of control as 1.0 with a standard deviation. EGCG and insulin suppressed the elevated levels induced by the treatment with Dex/cAMP in rat hepatoma H4IIE cells. EGCG and insulin also inhibited the gene expression of HNF4α. Copyright © 2010. Biomedical Research Press. Reproduced from Yasui K, Tanabe H, Okada N, Fukutomi R, Ishigami Y, Isemura M. Effects of catechin-rich green tea on gene expression of gluconeogenic enzymes in rat hepatoma H4IIE cells. Biomed Res. 2010;31(3):183–189.¹⁸
Abbreviations: Dex, dexamethasone; cAMP, cyclic adenosine monophosphate; EGCG, (−)-epigallocatechin gallate; G6Pase, glucose-6-phosphatase; HNF4α, hepatocyte nuclear factor 4α; PEPCK, phosphoenolpyruvate carboxykinase.

Table 1 Effects of green tea intake on hepatic mRNA expression and serum protein levels of inflammatory cytokines²⁴

Group	mRNA (% of control)		Protein (ng/mL)
	TNF-α	IL-1β	TNF-α	IL-1β
I (control)	100±28	100±16	<0.7	<0.7
II	603±102^a	281±46^a	23.7±5.5^b	68.3±5.9^b
III	366±112	171±26	13.0±1.7^b	30.3±8.3^b
IV	166±67	89±8	<0.7	<0.7

Notes: Hepatitis was induced in rats by peritoneal injection of galactosamine in groups II and III. Rats groups III and IV received the catechin-rich green tea beverage, while groups I and II received water.

a Significantly different from other groups at P<0.05;

b significantly different between groups II and III at P<0.05. Copyright © 2005. Biomedical Research Press. Reproduced from Abe K, Ijiri M, Suzuki T, Taguchi K, Koyama Y, Isemura M. Green tea with a high catechin content suppresses inflammatory cytokine expression in the galactosamine-injured rat liver. Biomed Res. 2005;26(5):187–192.²⁴

Abbreviations: mRNA, messenger RNA; TNF-α, tumor necrosis factor-α; IL-1β, interleukin-1β.

Figure 3 Effect of green tea catechins on learning ability in SAMP10 mice.

Notes: The time needed for acquisition of the avoidance response was measured in mice that had consumed green tea catechins (hatched column) and in control mice (open column). ^#Three experimental groups consumed catechins during 9 to 11 months, 6 to 11 months, and 3 to 11 months of age. Each value represents a mean ± SEM. (*P<0.05). Reproduced with permission from Yakugaku Zasshi. Volume 135 No1. © 2015 The Pharmaceutical Society of Japan.³²
Abbreviation: SEM, standard error of mean.

Table 2 Epidemiological studies on the association of green tea and the risk of human cancer^a

Cancer site	Study type/conditions	Outcomes
Breast	Meta-analysis of three CCS, with 5,062 cases and 5,483 controls Meta-analysis of five PCS, with 5,062 cases and 5,483 controls	70% risk reduction in the highest consumption compared with the no/low consumption No risk reduction
Colorectum	PCS with 8.9 years of follow-up for >60,000 Chinese individuals, aged 45-74 years PCS with 16 years of follow-up for 18,244 men PCS with 46,023 men and 50,139 women	Nonsignificant risk increase in male consumers compared with male nonconsumers 60% risk reduction in men with the highest urinary levels compared with those with undetectable levels of epigallocatechin No risk reduction
Esophagus	Review of 15 studies	Significantly reduced risk (six studies), nonsignificant low risk reduction (four studies), significantly increased risk (three studies), and null association (two studies)
Liver	PCS with 12.8 years follow-up for 60,076 men and 29,713 women, aged 25-69 years PCS with >9 years follow-up for 41,761 Japanese individuals aged 40-79 years	9% and 49% risk reduction in male and female tea consumers (at least four times a week), respectively, compared with other consumers 42% risk reduction in consumers of ≥5 cups/d compared with those of < 1 cup/d
Lung	Review of 12 studies Meta-analysis of 22 studies	Significantly reduced risk (five studies), nonsignificant low risk reduction (three studies), significantly increased risk (one study), nonsignificantly increased risk (one study), and null association (two studies) 22% risk reductions in the highest consumers compared with the lowest consumers
Oral cavity	PCS with 10.3 years follow-up for 20,550 men and 29,671 women aged 40-79 years	69% risk reduction in female consumers of ≥5 cups/d compared with those of < 1 cup/d; no risk reduction in men
Prostate	PCS with 49,920 men aged 40-69 years	48% risk reduction of advanced cancer in consumers of ≥5 cups/d compared with no/lowest consumers
Stomach	Pooled analysis of six PCS for the Japanese population	21% risk reduction in female consumers of ≥5 cups/d compared with those of < 1 cup/d; no risk reduction in men

Note:

a These data are selected from those discussed by Yuan.⁶

Abbreviations: CCS, case-control studies; PCS, prospective cohort studies.

Yasui K, Tanabe H, Okada N, Fukutomi R, Ishigami Y, Isemura M. Effects of catechin-rich green tea on gene expression of gluconeogenic enzymes in rat hepatoma H4IIE cells. Biomed Res. 2010;31(3):183–189.

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Abe K, Ijiri M, Suzuki T, Taguchi K, Koyama Y, Isemura M. Green tea with a high catechin content suppresses inflammatory cytokine expression in the galactosamine-injured rat liver. Biomed Res. 2005;26(5):187–192.

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Unno K, Prevention of senescence and stress by food consumption. Yakugaku Zasshi. 2015;135(1):41–46.

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Yuan JM. Cancer prevention by green tea: evidence from epidemiologic studies. Am J Clin Nutr. 2013;98(Suppl 6):1676–1681.

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