Catechins and resveratrol as protective polyphenols against beta-amyloid-induced toxicity: Possible significance to Alzheimer’s disease

Polyphenols have recently received particular attention because of their possible preventive role in the incidence of agerelated cognitive deficits and neurological disorders. Recent evidence from epidemiological studies has shown that beverages or food enriched in polyphenols are related to a low risk of dementia such as Alzheimer's disease (AD). These findings are in accordance with animal and cell culture studies indicating that catechins (or flavanols) and resveratrol display neuroprotective abilities or reverse cognitive deficits. Using cultured rat hippocampal neuronal cells, we investigated the neuroprotective abilities of various catechin ingredients of green tea and red wine against toxicity induced by free radicals and betaamyloid (Aß) peptides, in respect to the possible deleterious role of these agents in age-related neurological disorders. Our studies, along with those obtained by other groups, indicated that these beneficial effects appeared to be only partly attributable to their well-known antioxidant activities, but also to their ability to directly Correspondence/Reprint request: Dr. Stéphane Bastianetto, Douglas Mental Health University Institute, 6875 LaSalle Boulevard, Verdun, Québec, H4H 1R3, Canada. E-mail: [email protected] Stéphane Bastianetto et al. 146 inhibit cell death produced by Aß peptides, and to modulate intracellular signaling pathways and gene expression associated with cell death/survival as well. We summarize in this review the purported beneficial effects of polyphenols in human as well in in vitro and animal models of neurotoxicity. We will then focus on the possible mechanisms underlying their neuroprotective effects and finally discuss possible clinical implications and the possible role of polyphenols as therapeutic agents.