Mechanisms of Neuroprotection by Quercetin: Counteracting Oxidative Stress and More

Abstract

Increasing interest has recently focused on determining whether several natural compounds, collectively referred to as nutraceuticals, may exert neuroprotective actions in the developing, adult, and aging nervous system. Quercetin, a polyphenol widely present in nature, has received the most attention in this regard. Several studies in vitro, in experimental animals and in humans, have provided supportive evidence for neuroprotective effects of quercetin, either against neurotoxic chemicals or in various models of neuronal injury and neurodegenerative diseases. The exact mechanisms of such protective effects remain elusive, though many hypotheses have been formulated. In addition to a possible direct antioxidant effect, quercetin may also act by stimulating cellular defenses against oxidative stress. Two such pathways include the induction of Nrf2-ARE and induction of the antioxidant/anti-inflammatory enzyme paraoxonase 2 (PON2). In addition, quercetin has been shown to activate sirtuins (SIRT1), to induce autophagy, and to act as a phytoestrogen, all mechanisms by which quercetin may provide its neuroprotection.

A new validated HPLC method for the determination of quercetin: Application to study pharmacokinetics in rats

“…Recently, quercetin has gained great scientific and clinical interests since it can improve mental/ physical performance and decrease infection risk added to potential benefits to overall health, like anti-carcinogenic, anti-inflammatory, antioxidant, inhibition of lipid peroxidation, platelet aggregation and capillary permeability (Davis, Murphy, & Carmichael, 2009;D'Andrea, 2015). Several clinical trials and animal experimentations have suggested that QR may be a promising natural treatment for both inflammatory skin diseases and neurological diseases either against neurotoxic chemicals or in neurodegenerative diseases (Karuppagounder et al, 2016;Costa, Garrick, Roque, & Pellacani, 2016).…”

Comparative effects of quercetin and hydroalcoholic extract ofOtostegia persicaboiss with atorvastatin on atherosclerosis complication in male wistar rats

“…Due to the reduced levels of lipids and decreased lipid oxidation along with reduction in total weight gain, quercetin improved symptoms of histological atherosclerosis in aorta (isolated from male Wistar strain rats). The reduction of oxidative enzyme activity by quercetin was recorded during the Lucio G. Costa experiment (2016‐Hindawi Publishing Corporation) indicating a significant reduction in the ROS level compared to the inflammatory state (Costa, Garrick, Roque, & Pellacani, ). The findings of a research by Paulo Afonso Ribeiro Jorge et al (‐Arquivos Brasileiros de Cardiologia journal) indicated a significant increase in LDL and cholesterol levels as well as plasma MDA and lipid oxidation and formation of atherosclerosis in the aorta (Jorge et al, ).…”

Protective effect of quercetin on bupivacaine-induced neurotoxicity via T-type calcium channel inhibition

“…Quercetin has been shown to exert protective effects against cardiovascular diseases like atherosclerosis and ischemia reperfusion-induced injury, as well as anti-cancer and anti-inflammatory effects [12]. Recent studies have also revealed the neuro-protective effects of quercetin in many neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease, and against hypoxiainduced injury and neurotoxic chemical-induced damage [13,14]. However, the mechanisms underlying these effects were not fully understood.…”