Determination of the influence of IR radiation on the antioxidative network of the human skin.

Production of free radicals in the human skin subsequent to IR irradiation has been demonstrated by means of two different methods. The first technique, based on resonance Raman spectroscopy, enables the non-invasive measurements of the kinetics of cutaneous carotenoid antioxidants beta-carotene and lycopene, subsequent to IR irradiation. Obtained degradation of the cutaneous carotenoids was a hint but not evidence that IR irradiation can produce free radicals in the skin. Therefore, the direct observation sustaining the production of free radicals subsequent to IR irradiation in the skin was performed in-vitro by electron paramagnetic resonance spectroscopy. Enzymatic processes as well as heat shock-induced radicals in the human skin are presumably involved in the energy transfer from IR irradiation into the molecules of the skin. Protection strategy for human skin against IR-induced free radicals based on the increase in the concentration of antioxidants by means of antioxidant-rich supplementation is discussed.