Photoprotective Activity of Melanin Preparations in Human Skin Exposed to UV Irradiation: Dependence on Previous Photoexposure

Photoprotective effects of three melanin preparations (from black yeast fungi and Sepia sp.) were studied. These preparations in aqueous solutions (5 μg/ml, dark exposure for 7 days) demonstrated high photomodification capacity upon exposure to visible light in doses of up to 1.8 kJ/m2. Preliminary exposure of these solutions to visible light in a dose of 360 kJ/m2 notably decreased the photoprotective effect of melanins during UV exposure of the skin treated with these solutions (at UV dose of 3.4 kJ/m2). This necessitates empirical selection of the dose and storage condition of melanin preparations for attaining the optimal photoprotective effect.