Screening for new antioxidative compounds for topical administration using skin lipid model systems.

OBJECTIVE

The effects of forty seven different substances (drugs, plant extracts, plant ingredients and polysaccharides) on UV irradiation induced lipid peroxidation were investigated.

METHODS

Two lipid systems of different complexity were used as in vitro screening models. Iron ions were added as transition metal catalysts. A UV irradiation device was used to create high level radiation. The amount of lipid peroxidation secondary products was quantified by the thiobarbituric acid assay detecting malondialdehyde.

RESULTS

The screening for antioxidative compounds for topical administration resulted in new, interesting findings. In the drug testings amantadine, bufexamac, tryptophan, melatonin, propranolol and hyaluronic acid were found to act antioxidatively whereas for ascorbic acid pro-oxidative effects were determined. Buckwheat extract significantly reduced the level of irradiation induced lipid peroxidation as well as the extracts of St. John's Wort, melissa and sage. The resistant starch novelose 330 and the samples of locust bean gum from a swing mill grinding series showed lipid protection after UV irradiation in the polysaccharide test rows.

CONCLUSIONS

Human skin is constantly exposed to UV light and oxygen. Therefore, the administration of protectors in cosmetic formulations or sunscreens, as found in this study, may be helpful for the protection of the human skin against UV induced damage. In vivo experiments with substances found as protectors should follow to allow in vitro-in vivo correlation and clinical interpretation of the data.