ABSTRACT
Oxidation is the transfer of electrons from an atom or molecule (oxidizable substrate) to another (electron acceptor or prooxidant) and repre sents an essential part of aerobic life. Oxygen itself is the most important electron acceptor in the respiratory chain, a biochemical process which produces energy in the form of adenosine triphosphate. Oxidative stress which leads to an excess of oxidation, however, plays an important role in the development of several diseases and ageing (Hailiwell and Gutteridge 1999, Diplock et ah 1998). Atherosclerosis, for example, in volves peroxidation of lipoproteins thus forming so-called foam cells (Bankson et ah, 1993), and oxidative damage of DNA can lead to muta tions and cancer (Bankson et ah 1993, Hailiwell 1999, Wiseman and Hailiwell 1996). Neurodegeneration as seen in Alzheimer's disease, car diovascular diseases other than atherosclerosis, and diabetes are also associated with oxidative stress (Dhalla et ah 2000, Vendemiale et ah 1999). Sies (1991) defined oxidative stress as: "a disturbance in the pro oxidant-antioxidant balance in favour of the former, leading to potential damage". The most prominent pro-oxidants in living organisms are rep resented by reactive oxygen and nitrogen species (ROS/RNS), as shown in Table 9.1.
