title: Cutaneous photoprotection from ultraviolet injury by green tea polyphenols.
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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Dermatology, Case Western Reserve, Cleveland, Ohio, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Elmets
authors.forename: D
authors.initials: D
authors.lastname: Singh
authors.forename: K
authors.initials: K
authors.lastname: Tubesing
authors.forename: M
authors.initials: M
authors.lastname: Matsui
authors.forename: S
authors.initials: S
authors.lastname: Katiyar
authors.forename: H
authors.initials: H
authors.lastname: Mukhtar
mesh_terms: D000287:Administration, Topical; D000293:Adolescent; D000328:Adult; D018890:Chemoprevention; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D004890:Erythema / Q000503:physiopathology / Q000517:prevention & control; D005260:Female; D005419:Flavonoids; D006801:Humans; D008297:Male; D008875:Middle Aged; D010636:Phenols / Q000494:pharmacology*; D011108:Polymers / Q000494:pharmacology*; D059808:Polyphenols; D012867:Skin / Q000473:pathology; D013471:Sunburn / Q000503:physiopathology / Q000517:prevention & control*; D013473:Sunscreening Agents / Q000494:pharmacology*; D013662:Tea / Q000737:chemistry*; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D005419:Flavonoids; D010636:Phenols; D011108:Polymers; D059808:Polyphenols; D013473:Sunscreening Agents; D013662:Tea