Photochemoprevention by botanical antioxidants.

The trend towards an increase in incidence and higher prevalence of skin cancer makes identification of effective chemopreventive agents an urgent priority. Excessive exposure to solar ultraviolet (UV) B radiation has been implicated as its main cause. Since these trends are likely to continue in the foreseeable future, the adverse effect of UVB has become a major human health concern. Therefore, the development of novel strategies to reduce the occurrence of skin cancer has become a highly desirable goal. Because UV radiation is known to cause excessive generations of reactive oxygen species (ROS) which in turn results in a situation known as oxidative stress, the approaches aimed at counteracting ROS production may be useful for the prevention of skin cancer. One approach to reduce its occurrence is through 'photochemoprotection', which we define as 'the use of agents capable of ameliorating the adverse effects of UVB on the skin'. Among many photochemoprotective agents, botanical antioxidants are showing promise. This review focuses on photochemopreventive effects of selected botanical antioxidants. We suggest that the use of botanical antioxidants in combination with the use of sunscreens and educational efforts to avoid excessive sun exposure may be an effective strategy for reducing incidence of skin cancer and other UV-mediated damages in humans. Copyright 2002 S. Karger AG, Basel