History of a Concept

The free radicals which provided the impetus for life’s beginning also damage the same biomolecules that they helped to originate. Biological life is a combustion process which needs oxygen, but it is also endangered by reactive oxygen metabolites, so-called reactive oxygen species. It was suggested by Harman that life originated as a result of free radical reactions, selected free radical reactions to play a major part in metabolism, and assured evolution by employing them to provide for mutation and death (Harman 1984). The historical roots of the concept of oxidative injury in biological systems, and particularly in dermatopathology, are heterogeneous.