J Korean Soc Emerg Med.  2009 Apr;20(2):170-176.

Neuroprotective Effect of Quercetin against Damage Induced by Oxygen Deprivation in Cultured Rat Cortical Neurons

• Kim H
• Park JI
• Lee SW
• Park JS

Abstract

PURPOSE: Neuronal hypoxia is clinically related to stroke, cardiac arrest, asphyxia, and various cases involving metabolic encephalopathy, which has led to much research looking for new neuroprotective strategies. Quercetin belongs to an extensive class of polyphenolic flavonoid compounds, which are almost ubiquitous in plants and plant food sources. Quercetin is known as a strong free radical scavenger and an inhibitor of the production of reactive oxygen species (ROS). However, the effects of quercetin on hypoxia-induced oxidative cell damage have rarely been investigated. This report describes studies in cultured rat cortical neurons on the cellular effects of quercetin on neural damage induced by oxygen-deprivation.
METHODS
The experiment was conducted in vitro using primary culture of rat cortical neurons. Hypoxia induction was performed with a hypoxic chamber. The free radical scavenging activity of quercetin was assayed in cell-free systems using a stable free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH). Cytotoxicity was studied with the MTT method. The optical density of the neurons was measured at 540 nm using an ELISA reader. We used an inverted microscope to examine the morphological changes that followed hypoxia induction and quercetin treatment.
RESULTS
An anti-DPPH radical assay showed that quercetin inhibited the production of DPPH radicals in vitro and that its radical scavenging activity was superior to ascorbic acid and n-acetylcysteine. According to the MTT assay, incubation of cortical neurons with quercetin protected the neurons from hypoxia-induced cytotoxicity.
CONCLUSIONS
The results of this study suggest that at a low concentration (100 nM) quercetin has a neuroprotective effect on hypoxia-induced neuronal cell death; at a high concentration (100 uM) the protective effects for hypoxiainduced neuronal damage were reduced because of quercetin's apoptotic effects.

Keyword

Hypoxia; Quercetin; Antioxidants; Cortical neurons

MeSH Terms

Acetylcysteine
Animals
Anoxia
Antioxidants
Ascorbic Acid
Asphyxia
Biphenyl Compounds
Brain Diseases, Metabolic
Cell-Free System
Enzyme-Linked Immunosorbent Assay
Heart Arrest
Neurons
Neuroprotective Agents
Oxygen
Picrates
Plants
Quercetin
Rats
Reactive Oxygen Species
Stroke
Acetylcysteine
Antioxidants
Ascorbic Acid
Biphenyl Compounds
Neuroprotective Agents
Oxygen
Picrates
Quercetin
Reactive Oxygen Species