Effects of Polyphenols on Brain Ageing and Alzheimer’s Disease: Focus on Mitochondria

Abstract

The global trend of the phenomenon of population ageing has dramatic consequences on public health and the incidence of neurodegenerative diseases. Physiological changes that occur during normal ageing of the brain may exacerbate and initiate pathological processes that may lead to neurodegenerative disorders, especially Alzheimer's disease (AD). Hence, the risk of AD rises exponentially with age. While there is no cure currently available, sufficient intake of certain micronutrients and secondary plant metabolites may prevent disease onset. Polyphenols are highly abundant in the human diet, and several experimental and epidemiological evidences indicate that these secondary plant products have beneficial effects on AD risks. This study reviews current knowledge on the potential of polyphenols and selected polyphenol-rich diets on memory and cognition in human subjects, focusing on recent data showing in vivo efficacy of polyphenols in preventing neurodegenerative events during brain ageing and in dementia. Concentrations of polyphenols in animal brains following oral administration have been consistently reported to be very low, thus eliciting controversial discussion on their neuroprotective effects and potential mechanisms. Whether polyphenols exert any direct antioxidant effects in the brain or rather act by evoking alterations in regulatory systems of the brain or even the body periphery is still unclear. To understand the mechanisms behind the protective abilities of polyphenol-rich foods, an overall understanding of the biotransformation of polyphenols and identification of the various metabolites arising in the human body is also urgently needed.

A Human-Based Integrated Framework forAlzheimer’s Disease Research

“…The study of their effects at the gene expression level, by means of nutrigenomic analyses, is a field of broad scientific interest [77,78]. Despite some conflicting evidences, plant-based, plant-rich diets and plant-derived bioactive nutrients appear to inhibit neuroinflammation and neurodegeneration molecular and cellular processes [79] and seem to be particularly beneficial in the management of early stages of cognitive impairment [80][81][82][83][84]. Some nutrigenetic studies have highlighted correlations between specific nutrient intakes and single-nucleotide polymorphisms.…”

Biography of biophenols: past, present and future

“…Biophenols are reported to affect various body systems, modulate immunity and fight pathogens and neoplasms [13]. Further, biophenols are proclaimed to affect mood, behaviour, memory and cognition [31][32][33][34][35]. Biophenols demonstrated-at least in vitro-abilities to modulate cell signalling pathways, react with specific receptors, interfere with cell division, modulate enzyme activities, regulate gene expression and affect epigenetics [13].…”

Cholinesterase Inhibitor Donepezil Increases Mitochondrial Biogenesis through AMP-Activated Protein Kinase in the Hippocampus

“…Brain hypometabolism associated with mitochondrial dysfunction has been recognized as another crucial target for AD treatment [10,11,12,13,14,15]. It was found that mitochondrial dysfunction precedes plaque formation in transgenic AD model mice [16,17].…”