Topical beta-carotene is converted to retinyl esters in human skin ex vivo and mouse skin in vivo

Exp Dermatol. 2004 Sep;13(9):558-61. doi: 10.1111/j.0906-6705.2004.00194.x.

Abstract

Human epidermis contains endogenous retinoids (retinol and retinyl esters) and carotenoids (mostly beta-carotene). Previous studies have shown that the enzymes involved in retinoid metabolism are present in human epidermis. There is still a controversy about the presence in the skin of the enzymes able to convert beta-carotene into vitamin A (retinol), although a recent study demonstrated the conversion of beta-carotene into retinol in human cultured epidermal cells. In this study, we addressed the question of the possible bioconversion of topical beta-carotene into vitamin A or derivatives by human and mouse skin. Surgically excised human abdominal skin was mounted on Franz perfusion chambers to assess the cutaneous penetration of topical beta-carotene as well as its metabolism, after a 24-h incubation period, whereas hairless mice received topical beta-carotene 24 h before assaying epidermal beta-carotene and retinoid concentrations. Epidermal retinoid and beta-carotene concentrations were determined by high-pressure liquid chromatography. Topical beta-carotene penetrated well into human and mouse epidermis and induced a 10-fold (human) and a threefold (mouse) increase of epidermal retinyl esters, which demonstrates that topical beta-carotene is converted into retinyl esters by human and mouse epidermis and thus appears as a precursor of epidermal vitamin A.

MeSH terms

  • Administration, Topical
  • Animals
  • Diffusion Chambers, Culture
  • Epidermis / drug effects*
  • Epidermis / metabolism*
  • Esters / metabolism
  • Female
  • Humans
  • In Vitro Techniques
  • Mice
  • Mice, Hairless
  • Vitamin A / metabolism*
  • beta Carotene / pharmacokinetics*

Substances

  • Esters
  • beta Carotene
  • Vitamin A