Interaction between free radicals and antioxidants in human skin

Abstract

Free radicals are produced in the human body as a result of the metabolism [1, 2]. They are important for signalling processes in the organism [1, 3] as well as disinfector against viruses and bacteria [4]. If their concentration exceeds a critical value, these highly reactive molecules can destroy cells and cell compartments and cause serious damage to the human body [5, 6]. An enhanced radical formation is due to inflammatory processes in the human body or to environmental influences [7, 8]. In this context, high doses of solar radiation are dangerous [9]. Enhanced UV doses do not only evoke sunburns and skin aging but induce even skin cancer if significant amounts of free radicals are generated in the skin [10]. With the antioxidant protection system, the human organism has developed a defense mechanism against the destructive effect of the free radicals. The most important antioxidants in this defense system are the vitamins, the carotenoids, and some enzymes [11, 12]. The antioxidants are capable of neutralizing the free radicals before the same start damaging the body. Most of these antioxidants cannot be generated by the human body automatically, but must be taken in with food rich in fruit and vegetables. If the free radicals exceed a critical level, the antioxidants are destroyed, too. Thus, the detection of antioxidants in tissue permits at the same time conclusions to be drawn about the formation of radicals [13].