Cutaneous photoprotection from ultraviolet injury by green tea polyphenols

Background: In animal models, extracts from green tea have been shown to be remarkably effective at reducing the severity of adverse human health effe cts of overexposure to ultraviolet (UV) radiation. Although sunscreens and other photoprotective measures have traditionally been used for this purpos e, there is a need for additional measures and natural products are increas ingly 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 si tes were exposed to a 2 minimal erythema dose solar simulated radiation. UV -treated skin was examined clinically for UV-induced erythema, histological ly for the presence of sunburn cells or Langerhans cell distributions, or b iochemically for W-induced DNA damage. Results: Application of green tea extracts resulted in a dose-dependent inh ibition of the erythema response evoked by UV radiation. The (-) -eppigallo catechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate (ECG) polyphenolic fractions were most efficient at inhibiting erythema, whereas (-)-epigalloc atechin (EGC) and (-)-epicatechin (EC) had little effect. On histologic exa mination, skin treated with green tea extracts reduced the number of sunbur n 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 chemopreventiv e agents for many of the adverse effects of sunlight on human health find m ay thus serve as natural alternatives for photoprotection.