Neuroprotective Mechanisms of Natural Polyphenolic Compounds

Natural polyphenols have been reported to exert beneficial effects in preventing cardiovascular diseases but their neuroprotective mechanisms were studied much less. The review is focused on biochemical pathways and molecular neuroprotective mechanisms of natural polyphenols in the brain particularly; of course in close relation to neurophysiological and pathophysiological consequences. This review provides the evidence that antioxidant activity, mainly inhibition of the NADPH oxidase and subsequent reactive oxygen species generation; a balance in NO production from different NO synthase isoforms; reduction of neuroinflammation via attenuation of the release of cytokines and downregulation of the pro-inflammatory transcription factors; and the potential to modulate signalling pathways such as mitogen-activated protein kinase cascade and cAMP response element-binding protein are responsible for the neuroprotective actions of different natural polyphenols. These beneficial effects are mainly in demand in prevention of brain damage including ischemic stroke and neurodegenerative diseases, in the reduction of neuronal death, in memory improvement, as also for learning and general cognitive ability.