Generation of cellular reactive oxygen and nitrogen species by exposure to ultraviolet radiation.

Reactive oxygen and nitrogen species, such as superoxide and peroxynitrite anions, are produced in our body as a result of normal metabolic functions or under pathologic conditions (oxidative and nitro-oxidative stress). A well-documented battery of antioxidant enzymes and cofactors are in place to fight this stress and restore the redox balance of the cell. However, comprehensive information on the generation of these reactive species by exposing cell components to ultraviolet (UV) light, specifically UVA and UVB sunlight, is scarce or missing. In this short review, we attempt to cover several enzymes and cofactors that are targets of UV radiation as it relates to the production (or consumption) of these oxidants, and, when known, discuss the underlying mechanisms. Because of their key importance, UV light effects on DNA are briefly discussed.