Studies of the Benefits of Green Tea on the Skin Studies of the Benefits of Green Tea on the Skin Green tea
extract reduces induction of p53 and apoptosis in UVB-irradiated human skin independent
of transcriptional controls.
Mnich CD, Hoek
KS, Virkki LV, Farkas A,
Department of Dermatology, University Hospital of Zurich, Zurich, Switzerland. Abstract
Ultraviolet
(UV) irradiation plays a pivotal role in human skin carcinongenesis.
Preclinically, systemically and topically applied green tea extract (GTE) has
shown reduction of UV-induced (i) erythema, (ii) DNA damage, (iii) formation of
radical oxygen species and (iv) downregulation of numerous factors related to
apoptosis, inflammation, differentiation and carcinogenesis. In humans, topical
GTE has so far only been tested in limited studies, with usually very high GTE
concentrations and over short periods of time. Both chemical stability of GTE
and staining properties of highly concentrated green tea polyphenols limit the
usability of highly concentrated green tea extracts in cosmetic products. The
present study tested the utility of stabilized low-dose GTE as
photochemopreventive agents under everyday conditions. We irradiated with up to
100 mJ/cm(2) of UVB light skin patches which were pretreated with either OM24-containing
lotion or a placebo lotion. Biopsies were taken from both irradiated and
un-irradiated skin for both immunohistochemistry and DNA microarray analysis.
We found that while OM24 treatment did not significantly affect UV-induced
erythema and thymidine dimer formation, OM24 treatment significantly reduced
UV-induced p53 expression in keratinocytes. We also found that OM24 treatment
significantly reduced the number of apoptotic keratinocytes (sunburn cells and
TUNEL-positive cells). Care-fully controlled DNA microarray analyses showed
that OM24 treatment does not induce off-target changes in gene expression,
reducing the likelihood of unwanted side-effects. Topical GTE (OM24) reduces
UVB-mediated epithelial damage already at low, cosmetically
usable concentrations, without tachyphylaxis over 5 weeks, suggesting GTE as
suitable everyday photochemopreventive agents.
Studies
Relating to the Benefits of Green Tea on the Skin
Photodermatol
Photoimmunol Photomed. 2007 Feb; 23(1):48-56.
Photoprotective
effects of green tea polyphenols.
Yusuf N, Irby
C, Katiyar SK, Elmets CA.
Department of
Dermatology, University of Alabama at Birmingham, Birmingham, AL
35294, USA. [email protected]
Abstract
Non-melanoma
skin cancer is the most common malignancy in humans and is equivalent to the
incidence of malignancies in all other organs combined in the United States.
Current methods of prevention depend on sunscreens in humans, efficacy of which
is largely undetermined for non-melanoma skin cancers. Green tea polyphenols
have the greatest effect with respect to chemoprevention and have been found to
be most potent at suppressing the carcinogenic activity of UV radiation. They
protect against many of the other damaging effects of UV radiation such as
UV-induced sunburn response, UV-induced immunosuppression and photoaging of the
skin. They exert their photoprotective effects by various cellular, molecular
and biochemical mechanisms in in vitro and in vivo systems. Green tea
polyphenols thus have the potential, when used in conjunction with traditional
sunscreens, to further protect the skin against the adverse effects of
ultraviolet radiation.
Exp Dermatol.
2009 Jun;18(6):522-6.
Topical
application of green and white tea extracts provides protection from solar-simulated
ultraviolet light in human skin.
Camouse MM,
Domingo DS, Swain FR
Department of
Dermatology, University Hospitals Case Medical Center
Cleveland, OH
44106, USA.
Abstract
BACKGROUND: Tea
polyphenols have been found to exert beneficial effects on the skin via their
antioxidant properties. AIMS: We sought to determine whether topical
application of green tea or white tea extracts would prevent simulated solar
radiation-induced oxidative damages to DNA and Langerhans cells that may lead
to immune suppression and carcinogenesis. METHODS: Skin samples were analyzed
from volunteers or skin explants treated with white tea or green tea after UV
irradiation. In another group of patients, the in vivo immune protective
effects of green and white tea were evaluated using contact hypersensitivity to
dinitrochlorobenzene. RESULTS: Topical application of green and white tea
offered protection against detrimental effects of UV on cutaneous immunity.
Such protection is not because of direct UV absorption or sunscreen effects as
both products showed a sun protection factor of 1. There was no significant
difference in the levels of protection afforded by the two agents. Hence, both
green tea and white tea are potential photo-protective agents that may be used
in conjunction with established methods of sun protection.
Exp Dermatol.
2009 Jan;18(1):69-77. Epub 2008 Jul 9.
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