title: Topical isoflavones provide effective photoprotection to skin.
abstract: OBJECTIVE
  Isoflavones, one main group of phytoestrogens, have antioxidative and photoprotective effects in cellular and mouse studies. The aim of this study is to obtain a more comprehensive understanding of the isoflavone-mediated photoprotection with the pig skin model, a more human-resembling model.
  
  
  METHODS
  The pig skin was treated with five well-known isoflavone compounds (genistein, equol, daidzein, biochanin A, and formononetin) and one antioxidant combination solution of 15% vitamin C and 1% vitamin E and 0.5% ferulic acid (CEF) daily for 4 days. Skin was irradiated with solar-simulated UV irradiation, 1 to 5 minimal erythema dose (MED) at 1-MED intervals. Evaluation was carried out 24 h later by colorimeter-measured erythema and sunburn cell numbers.
  
  
  RESULTS
  Topical application of 0.5% solutions of three individual phytoestrogens - genistein, daidzein, biochanin A - are better than similar solutions of equol or formononetin in protecting pig skin from solar-simulated ultraviolet (SSUV)-induced photodamage, as measured by sunburn cell formation and/or erythema. However, the protection was less than that provided by a topical combination antioxidant standard containing 15% L-ascorbic acid, 1%alpha-tocopherol, and 0.5% ferulic acid.
  
  
  CONCLUSIONS
  Isoflavones provide effective photoprotection and are good candidate ingredients for protection against ultraviolet (UV) photodamage.
authors: Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taipei, Taiwan. lindajylin@adm.cgmh.org.tw
authors: Jing-Yi
authors: JY
authors: Lin
authors: Joshua A
authors: JA
authors: Tournas
authors: James A
authors: JA
authors: Burch
authors: Nancy A
authors: NA
authors: Monteiro-Riviere
authors: Jan
authors: J
authors: Zielinski
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D003373:Coumaric Acids / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D060754:Equol; D019833:Genistein / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D007529:Isoflavones / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D008517:Phytotherapy; D010946:Plants, Medicinal; D012867:Skin / Q000187:drug effects* / Q000528:radiation effects; D013471:Sunburn / Q000473:pathology / Q000517:prevention & control*; D013472:Sunlight / Q000009:adverse effects; D013473:Sunscreening Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D013552:Swine; D014810:Vitamin E / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: C007610:4',7-dihydroxy-3,4-dihydroisoflavone; D003373:Coumaric Acids; D004338:Drug Combinations; D007529:Isoflavones; D013473:Sunscreening Agents; D014810:Vitamin E; C007768:formononetin; D060754:Equol; C004742:daidzein; C004999:ferulic acid; D019833:Genistein; D001205:Ascorbic Acid; C004541:biochanin A