Free radical scavengers: chemical concepts and clinical relevance

Free radicals are involved in the pathology of many CNS disorders, like Par kinson's disease, Alzheimer's disease, or stroke. This discovery lead to th e development of many radical scavengers for the clinical treatment of neur odegenerative diseases. In this review, the different chemical concepts for free radical scavenging will be discussed: nitrons, thiols, iron chelators , phenols, and catechols. Especially catechols, like the naturally occurrin g flavonols, the synthetic drug nitecapone, or the endogenous catacholamine s and their metabolites, are of great interest, as they combine iron chelat ing with radical scavenging activity. We present data on the radical scveng ing activity of dopamine and apomorphine, which prevent lipid peroxidation in rat brain mitochondria and protect PC12 cells against H2O2-toxicity.