Oxidative stress, neurodegenerative pathologies

Copper is essential for some of the enzymes that have a role in brain metabolism. Sophisticated mechanisms balance copper import and export to ensure proper nutrient levels (homeostasis) while minimizing toxic effects. Several neurodegenerative diseases including AD are characterized by modified copper homeostasis. This change seems to contribute either directly or indirectly to increased oxidative stress, an important factor in neuronal toxicity. The association of misfolded proteins and modified copper homeostasis appears to be important in the pathological progression of AD [Donnelly et al., 2007],... 

Perry G., Taddeo M. A., Nunomura A., Zhu X. W., Zenteno-Savin T., Drew K. L., Shimohama S., Avila J., Castellani R. J., and Smith M. A. (2002). Comparative biology and pathology of oxidative stress in Alzheimer and other neurodegenerative diseases beyond damage and response. Comp. Biochem. Physiol. C-Toxicol. Pharmacol. 133 507-513. 

The pathological characteristic of Parkinson s disease is the selective degeneration of dopamine neurons in the pars compacta of the substantia nigra. The mechanism for the loss of neurons remains to be elucidated, and recently apoptosis has been proposed as a death process in Parkinson s disease. For example, the level of a product of the oxidative stress, 4-hydroxy-2-nonenal protein adduct, was found to increase in the nigral neurons of parkinsonian brains. Peroxynitrite (see Figure 13.6) has been proposed to be involved in the neuronal cell death in some neurodegenerative diseases, such as amyotrophic lateral sclerosis. 

Flavan-3-ols are a large class of flavanoids ubiquitous in plants [1-5] and widely found in a number of foods [6,7]. They represent an integral part of the human diet and are considered to be key compounds in the relationship between health and diet. Indeed, they are known to combat aging pathologies in which oxidative stress is involved such as cancers [8-10], and cardiovascular [11-13] and neurodegenerative [14] diseases. 

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