title: UV photoprotection by combination topical antioxidants vitamin C and vitamin E.
abstract: BACKGROUND
  Virtually all plants and animals protect themselves from the sun using vitamins C and E.
  
  
  OBJECTIVE
  The purpose of this study was to see if a combination of topical vitamins C and E is better for UV protection to skin than an equivalent concentration of topical vitamin C or E alone.
  
  
  METHODS
  We developed a stable aqueous solution of 15% L-ascorbic acid (vitamin C) and 1% alpha-tocopherol (vitamin E). We applied antioxidant or vehicle solutions to pig skin daily for 4 days. We irradiated (1-5x minimal erythema dose) control- and antioxidant-treated skin using a solar simulator with a 295-nm band-pass filter. On day 5, we measured antioxidant protection factor, erythema, sunburn cells, and thymine dimers.
  
  
  RESULTS
  The combination of 15% L-ascorbic acid and 1% alpha-tocopherol provided significant protection against erythema and sunburn cell formation; either L-ascorbic acid or 1% alpha-tocopherol alone also was protective but the combination was superior. Application during 4 days provided progressive protection that yielded an antioxidant protection factor of 4-fold. In addition, the combination of vitamins C and E provided protection against thymine dimer formation.
  
  
  CONCLUSIONS
  Appreciable photoprotection can be obtained from the combination of topical vitamins C and E. We suggest that these natural products may protect against skin cancer and photoaging.
authors.affiliation: Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Jing-Yi
authors.initials: JY
authors.lastname: Lin
authors.forename: M Angelica
authors.initials: MA
authors.lastname: Selim
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Shea
authors.forename: James M
authors.initials: JM
authors.lastname: Grichnik
authors.forename: Mostafa M
authors.initials: MM
authors.lastname: Omar
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Monteiro-Riviere
authors.forename: Sheldon R
authors.initials: SR
authors.lastname: Pinnell
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000627:therapeutic use*; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000627:therapeutic use*; D004338:Drug Combinations; D004890:Erythema / Q000517:prevention & control; D007150:Immunohistochemistry; D011740:Pyrimidine Dimers / Q000096:biosynthesis; D013471:Sunburn / Q000517:prevention & control*; D013552:Swine; D014810:Vitamin E / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D000975:Antioxidants; D004338:Drug Combinations; D011740:Pyrimidine Dimers; D014810:Vitamin E; D001205:Ascorbic Acid