Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2011 Jun;55(6):844-54.
doi: 10.1002/mnfr.201000641. Epub 2011 May 2.

The role of antioxidant versus pro-oxidant effects of green tea polyphenols in cancer prevention

Sarah C Forester  1 , Joshua D Lambert
Affiliations
Review

The role of antioxidant versus pro-oxidant effects of green tea polyphenols in cancer prevention

Sarah C Forester et al. Mol Nutr Food Res. 2011 Jun.

Abstract

Consumption of green tea (Camellia sinensis) may provide protection against chronic diseases, including cancer. Green tea polyphenols are believed to be responsible for this cancer preventive effect, and the antioxidant activity of the green tea polyphenols has been implicated as a potential mechanism. This hypothesis has been difficult to study in vivo due to metabolism of these compounds and poor understanding of the redox environment in vivo. Green tea polyphenols can be direct antioxidants by scavenging reactive oxygen species or chelating transition metals as has been demonstrated in vitro. Alternatively, they may act indirectly by upregulating phase II antioxidant enzymes. Evidence of this latter effect has been observed in vivo, yet more work is required to determine under which conditions these mechanisms occur. Green tea polyphenols can also be potent pro-oxidants, both in vitro and in vivo, leading to the formation of hydrogen peroxide, the hydroxyl radical, and superoxide anion. The potential role of these pro-oxidant effects in the cancer preventive activity of green tea is not well understood. The evidence for not only the antioxidant, but also pro-oxidant, properties of green tea is discussed in the present review.

PubMed Disclaimer

Conflict of interest statement

Conflict of Interest

Neither author has a conflict of interest to disclose.

Figures

Figure 1
Figure 1
Chemical structures of the major green tea polyphenols. Structures shown: (1) Gallic acid, (2) (–)-gallocatechin, (3) (+)-catechin, (4) (–)-epigallocatechin, (5) (–)-epicatechin, (6) (–)-epigallocatechin gallate, (7) (–)-epicatechin gallate, (8) p-coumaroylquinic acid, and (9) (–)-gallocatechin gallate.
Figure 2
Figure 2
Scavenging and formation of ROS mechanisms by green tea polyphenols. These mechanisms are applicable to all green tea polyphenols, but (–)-Epigallocatechin gallate (6) is shown as a representative molecule.
Figure 3
Figure 3
Propose antioxidant and pro-oxidant effects of green tea polyphenols relevant to the prevention of cancer
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Yang CS, Wang X, Lu G, Picinich SC. Cancer prevention by tea: animal studies, molecular mechanisms and human relevance. Nat Rev Cancer. 2009;9:429–439. - PMC - PubMed
    1. Fukushima Y, Ohie T, Yonekawa Y, Yonemoto K, Aizawa H, Mori Y, Watanabe M, Takeuchi M, Hasegawa M, Taguchi C, Kondo K. Coffee and Green Tea As a Large Source of Antioxidant Polyphenols in the Japanese Population. J Agric Food Chem. 2009;57:1253–1259. - PubMed
    1. Baptista JAB, Tavares JFD, Carvalho RCB. Comparison of catechins and aromas among different green teas using HPLC/SPME-GC. Food Res Int. 1998;31:729–736.
    1. Shishikura Y, Khokhar S. Factors affecting the levels of catechins and caffeine in tea beverage: estimated daily intakes and antioxidant activity. J Sci Food Agric. 2005;85:2125–2133.
    1. Engelhardt UH, Lakenbrink C, Pokorny O. In: Nutraceutical Beverages: Chemistry, Nutrition, and Health Effects. Shahidi F, Weerasinghe DK, editors. Amer Chemical Soc; Washington: 2004. pp. 254–264.

MeSH terms

-