| |
Green tea polyphenols prevent UV-induced immunosuppression by rapid repair of DNA damage and enhancement of nucleotide excision repair genes.
Cancer Prev Res (Phila Pa). 2010 Feb;3(2):179-89
Katiyar SK,
Department of Dermatology, University of Alabama at Birmingham, 35294, USA.
Abstract
UV radiation-induced immunosuppression has been implicated in the development of skin cancers.
Green tea polyphenols (GTP) in drinking water prevent photocarcinogenesis in the skin of mice.
We studied whether GTPs in drinking water (0.1-0.5%, w/v) prevent UV-induced immunosuppression and (if so) potential mechanisms of this effect in mice.
GTPs (0.2% and 0.5%, w/v) reduced UV-induced suppression of contact hypersensitivity (CHS) in response to a contact sensitizer in local (58-62% reductions; P < 0.001) and systemic (51-55% reductions; P < 0.005) models of CHS.
Compared with untreated mice, GTP-treated mice (0.2%, w/v) had a reduced number of cyclobutane pyrimidine dimer-positive (CPD(+)) cells (59%; P < 0.001) in the skin, showing faster repair of UV-induced DNA damage, and had a reduced (2-fold) migration of CPD(+) cells from the skin to draining lymph nodes, which was associated with elevated levels of nucleotide excision repair (NER) genes.
GTPs did not prevent UV-induced immunosuppression in NER-deficient mice but significantly prevented it in NER-proficient mice (P < 0.001); immunohistochemical analysis of CPD(+) cells indicated that GTPs reduced the numbers of UV-induced CPD(+) cells in NER-proficient mice (P < 0.001) but not in NER-deficient mice. Southwestern dot-blot analysis revealed that GTPs repaired UV-induced CPDs in xeroderma pigmentosum complementation group A (XPA)-proficient cells of a healthy person but did not in XPA-deficient cells obtained from XPA patients, indicating that a NER mechanism is involved in DNA repair.
This study is the first to show a novel NER mechanism by which drinking GTPs prevents UV-induced immunosuppression and that inhibiting UV-induced immunosuppression may underlie the chemopreventive activity of GTPs against photocarcinogenesis.
|
Green tea and cancer prevention.
Nutr Cancer. 2010 Oct;62(7):931-7.
Honest Tea Press Releases
Herbal teas, including all the teas discussed in these pages, should not be consumed by persons who are pregnant or nursing, unless approved by your health care provider. Herbal teas may vary in their ingredients and some herbal tea components may interfere with other important medications. For example, there is some concern that green tea ingestion during pregnancy may reduce the absorption of folate, an important nutrient in fetal nervous system development.
keywords and tags:
tea, green tea, natural tea, red tea, african tea, white tea, chinese tea, black tea, tea benefits, green tea skin care products,green tea and weight loss, Chamomile Tea, herbal teas, mint tea, oolong tea, natural tea news, black dragon tea, hibiscus tea, new tea products, unsweetened tea, tazo tea, Pu-ehr tea, Earl Grey Tea,
Masala Indian Spiced Tea, Moroccan Tea, Mint Tea, Lemongrass Tea, Yerba Tea, Kombucha Tea
|
|
|
Learn about
Green Tea
Black Tea
Herbal Teas Pu-ehr Tea
Red Tea Chamomile Tea
Raspberry Tea |
White Tea
Tea Skin Care Products
At AllNaturalTea.com |
|
|
