Role of ascorbic acid in stratum corneum lipid models exposed to UV irradiation.
OBJECTIVE
The effects of ascorbic acid on Stratum corneum lipid models following ultraviolet irradiation were studied adding iron ions as transition metal catalysts.


METHODS
Lipid peroxidation was quantified by the thiobarbituric acid assay. The qualitative changes were studied on a molecular level by mass spectrometry. To elucidate the nature of free radical involvement we carried out electron paramagnetic resonance studies. The influence of ascorbic acid on the concentration of hydroxyl radicals was examined using the spin trapping technique. Moreover, we checked the vitamin's ability to react with stable radicals.


RESULTS
Ascorbic acid was found to have prooxidative effects in all lipid systems in a concentration dependent manner. The degradation products of ascorbic acid after its prooxidative action were detected. The concentration of the hydroxyl radicals in the Fenton assay was decreased by ascorbic acid. The quantification assay of 2,2-diphenyl-1-picrylhydrazyl hydrate showed reduced concentration levels of the stable radical caused by ascorbic acid.


CONCLUSIONS
Considering human skin and its constant exposure to UV light and oxygen, an increased pool of iron ions in irradiated skin and the depletion of co-antioxidants, the administration of ascorbic acid in cosmetic formulations or in sunscreens could unfold adverse effects among the Stratum corneum lipids.
Trommer
Hagen
H
Martin-Luther-University Halle-Wittenberg, School of Pharmacy, Institute of Pharmaceutics and Biopharmaceutics, Halle, Saale, Germany.
Böttcher
Roif
R
Pöppl
Andreas
A
Hoentsch
Joachim
J
Wartewig
Siegfried
S
Neubert
Reinhard H H
RH
D001205:Ascorbic Acid / Q000009:adverse effects / Q000502:physiology* / Q000528:radiation effects*; D004817:Epidermis / Q000378:metabolism / Q000528:radiation effects; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism / Q000528:radiation effects*; D008954:Models, Biological; D014466:Ultraviolet Rays / Q000009:adverse effects
D005609:Free Radicals; D008563:Membrane Lipids; D001205:Ascorbic Acid