Free radicals and antioxidants in human diseases

Abstract

Free radical reactions are involved in many of the effects constituting tissue damage, for example inflammation and damage to lipids, proteins, and DNA. Normal, healthy tissues produce and sequester free radical species as a part of daily respiratory and redox processes. However, if there is an enhancement of this background, ambient oxidation due to exposure to stress, inherent ageing processes, or environmental insults these cytotoxic free radical species can overwhelm the natural antioxidant / redox systems. Skin is continually exposed to environmental insult. Depending upon the insult, the damage to the epidermis and dermis may be subtle and undetectable; but cumulative, leading to a gradual reduction in the healthy skin status. In the case of a direct insult, such as ultraviolet (UV) radiation, free radical damage may manifest itself as a visible inflammatory sunburn reaction. Benefit could therefore be derived from the development of systems to counteract both the detectable as well as undetectable underlying effects of free radical damage to the skin. Animal studies have shown protection against oxidative damage by antioxidant supplementation. These antioxidant studies provide strong circumstantial evidence of a significant role for antioxidants in protecting skin against free radical - induced damage; however, no clinical studies have correlated antioxidants with healthy skin in humans. Antioxidant supplementation could also be applied towards other technologies, such as in hair products to prevent UV radiation - induced colour changes, in preservation of foods, and as retardants of steroid oxidation in deodorants. #