Cutaneous photoprotection from ultraviolet injury by green tea polyphenols - 02/09/11
Abstract |
Background: In animal models, extracts from green tea have been shown to be remarkably effective at reducing the severity of adverse human health effects of overexposure to ultraviolet (UV) radiation. Although sunscreens and other photoprotective measures have traditionally been used for this purpose, there is a need for additional measures and natural products are increasingly being explored for that purpose. Objective: Our purpose was to evaluate the effect of polyphenols from green tea on parameters associated with acute UV injury. Methods: Areas of skin of normal volunteers were treated with an extract of green tea or one of its constituents. Thirty minutes later, the treated sites were exposed to a 2 minimal erythema dose solar simulated radiation. UV-treated skin was examined clinically for UV-induced erythema, histologically for the presence of sunburn cells or Langerhans cell distributions, or biochemically for UV-induced DNA damage. Results: Application of green tea extracts resulted in a dose-dependent inhibition of the erythema response evoked by UV radiation. The (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate (ECG) polyphenolic fractions were most efficient at inhibiting erythema, whereas (-)-epigallocatechin (EGC) and (-)-epicatechin (EC) had little effect. On histologic examination, skin treated with green tea extracts reduced the number of sunburn cells and protected epidermal Langerhans cells from UV damage. Green tea extracts also reduced the DNA damage that formed after UV radiation. Conclusion: Polyphenolic extracts of green tea are effective chemopreventive agents for many of the adverse effects of sunlight on human health and may thus serve as natural alternatives for photoprotection. (J Am Acad Dermatol 2001;44:425-32)
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Supported by National Institutes of Health grants CA73096, CA79820 CA51802, and CA78809, National Cancer Institute Contract N01 CN-85083-57, American Institute for Cancer Research Grant 96B015, and by funds from Estee Lauder Companies, Inc. |
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Reprint requests: Craig A. Elmets, MD, EFH 414, 1530 Third Ave S, Birmingham, AL 35294-0009. E-mail: celmets@uab.edu. |
Vol 44 - N° 3
P. 425-432 - mars 2001 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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