ABSTRACT

This chapter covers the physiological roles and measurement of the chain-breaking antioxidants (CBAs). It is very interesting to note that the very ability for the CBAs to react with free radicals (electron transfer) also renders them electrochemically active. Molecules entering the probe are swept along in the perfusion medium and are collected outside the probe for analysis using a variety of analytical procedures. The chromagen is indistinguishable from the thiobarbituric acid-malondialdehyde reaction product, and the exact species undergoing reaction is unknown as is the reaction mechanism. By far the most promising techniques for trapping hydroxyl free radicals are considered to be electron spin resonance and aromatic hydroxylation. The action of N-acetylcysteine is thought to be through elevation of cysteine and/ or by the direct scavenging of free radical species. Damage to deoxyribonucleic acid resulting from its interaction with ionizing radiation or attack by free radicals has been suggested to play a major role in mutagenesis, carcinogenesis, aging, and cell death.