Polyphenols and Neurodegenerative Diseases: Potential Effects and Mechanisms of Neuroprotection

Abstract

The increase in people’s longevity has, consequently, led to more brain involvement and neurodegenerative diseases, which can become complicated and lead to chronic degenerative diseases, thereby presenting greater public health problems. Medicinal plants have been used since ancient times and contain high concentrations of molecules, including polyphenols. It has been proven that polyphenols, which are present in various natural sources can provide curative effects against various diseases and brain disorders through neuroprotective effects. These neuroprotective effects are mainly attributed to their ability to cross the blood–brain barrier, eliminate reactive oxygen species, and cause the chelation of metal ions. Polyphenols increase the concentration of neurotrophic factors and bind directly to the membrane receptors of these neurotrophic factors, to modulate and activate the signaling cascades that allow the plasticity, survival, proliferation, and growth of neuronal cells, thereby allowing for better learning, memory, and cognition. Moreover, polyphenols have no serious adverse side effects resulting from their consumption.

Unveiling the functional components and anti-Alzheimer's activity of Koelreuteria elegans (Seem.) A.C. Sm. using UHPLC-MS/MS and molecular networking

“…They have been perceived in several reports as anti-neuroinflammatory by blocking the release of cytokines (TNF-α and IL-1β), inhibiting NF-κB expression, and reducing intracellular Aβ and the hyperphosphorylation of tau. 50–53 The results of the study displayed that the fruit extract of K. elegans has a more potent anti-inflammatory effect than the leaf extract in a mice model of AD. The fruit extract reduced TNF-α, NF-κB, and IL-1β levels more than the leaf extract, which are all markers of inflammation and neurodegeneration in AD.…”

“…48 Several studies evaluated the biological activities of flavonoids as neuronal antioxidants, exhibiting anti-amyloidogenic and anti-inflammatory potential and neuroprotection and improving cognition. 50–55 K. elegans leaves and fruits are rich in flavonoids, which have potential against AD by regulating several important physiological responses. Quercetin, catechin-3-gallate, apigenin, apigenin hexoside, kaempferol and luteolin are detected in KEL and KEF.…”

Neuroprotective Effects of the Nutraceutical Dehydrozingerone and Its C2-Symmetric Dimer in a Drosophila Model of Parkinson’s Disease

“…Polyphenols can delay oxidative reactions in cells by rapidly donating protons to radicals or by forming complexes with pro-oxidant metals. Furthermore, polyphenols can interact with receptors or enzymes in signal translation, promoting an antioxidant condition [ 10 , 76 ].…”

“…As a matter of fact, many nutraceuticals and food-derived bioactive compounds, by virtue of their intrinsic properties, could have a dramatic role in reducing the risk factors for the arising of chronic neurodegenerative diseases. Focused emphasis has been given to the use of polyphenols, present in most vegetables, e.g., flavonoids, phenolic acids or curcuminoids, as therapeutic natural compounds against inflammation, neurodegeneration, and oxidative stress [ 9 , 10 , 11 ].…”

Black Chokeberry (Aronia melanocarpa) Juice Supplementation Improves Oxidative Stress and Aging Markers in Testis of Aged Rats

“…The presence of a greater number of blood vessels in the vicinity of Leydig cells is another sign of their increased activity and also a sign of improved nutrition of the Recently, it has been found that under conditions of oxidative stress due to aging, neurotrophins are oxidatively modified, thereby reducing their effectiveness [53]. On the other hand, there is evidence that polyphenols can enhance the synthesis of neurotrophic factors such as BDNF, NGF, neurotrophin 3 (NT3), and neurotrophin 4 (NT4), as well as increase their ability to bind directly to TRK-C receptors, regulating transcription, translation, proliferation, growth, and survival through pathways such as phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT), mitogen-activated protein kinase (MAPK), signal transducer, and activator of transcription 3 (STAT3), activating cAMP response elementbinding protein (CREB) [54]. There is a paucity of data in the literature on the effects of dietary polyphenols on neurotrophic factors in testes.…”