Carnosine and N-Acetylcarnosine Induce Inhibition of UVB Erythema in Human Skin

Background: Carnosine is a low molecular weight water soluble biological dipeptide, composed of alanine and histidine, present in a levorotatory form in mammalian tissues. Interesting activities are related to the detoxification from free radical species and byproducts of membrane lipids peroxidation. Objectives: The aim of the present study was to evaluate the photoprotective properties of carnosine and acetylated carnosine when applied to human skin. Materials and methods: Carnosine and N-acetylcarnosine at 0.5% solution in water were applied before and after UVB irradiation in twenty healthy volunteers with phototype 2 or 3. 9 patients were males and 11 females, 25 to 46 years of age. None of the patients had a positive case history for photodermatoses or had received any sun exposure. The minimal erythemal dose (MED) for UVB was determined before the study with a UVB Philips TL12 lamp with a radiance of 4 mW/cm and a 290 320 nm emission spectrum. Results: Carnosine solution obtained 3.6% reduction of erythema (compared to MED) and N-acetylcarnosine 7.3% reduction. Conclusions: An antioxidant capacity of N-acetylcarnosine and carnosine was shown, probably more significant with vehicles improving skin penetration of the substances through skin barrier. N-acetylcarnosine represents an interesting hydrophilic antioxidant for dermatological preparations.