Protective Effects of Walnut Extract Against Amyloid Beta Peptide-Induced Cell Death and Oxidative Stress in PC12 Cells

Abstract

Amyloid beta-protein (Aβ) is the major component of senile plaques and cerebrovascular amyloid deposits in individuals with Alzheimer’s disease. Aβ is known to increase free radical production in neuronal cells, leading to oxidative stress and cell death. Recently, considerable attention has been focused on dietary antioxidants that are able to scavenge reactive oxygen species (ROS), thereby offering protection against oxidative stress. Walnuts are rich in components that have anti-oxidant and anti-inflammatory properties. The inhibition of in vitro fibrillization of synthetic Aβ, and solubilization of preformed fibrillar Aβ by walnut extract was previously reported. The present study was designed to investigate whether walnut extract can protect against Aβ-induced oxidative damage and cytotoxicity. The effect of walnut extract on Aβ-induced cellular damage, ROS generation and apoptosis in PC12 pheochromocytoma cells was studied. Walnut extract reduced Aβ-mediated cell death assessed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) reduction, and release of lactate dehydrogenase (membrane damage), DNA damage (apoptosis) and generation of ROS in a concentration-dependent manner. These results suggest that walnut extract can counteract Aβ-induced oxidative stress and associated cell death.

A cross sectional study of the association between walnut consumption and cognitive function among adult us populations represented in NHANES

“…Amyloid beta-protein is the principal component of amyloid plaques in the brains of patients with AD (13). In cell lines, walnut extract reduces amyloid beta protein-induced oxidative stress and cell death (13,14). These research findings suggest that a diet rich in walnuts may help prevent and delay the onset of AD (12,14).…”

“…In cell lines, walnut extract reduces amyloid beta protein-induced oxidative stress and cell death (13,14). These research findings suggest that a diet rich in walnuts may help prevent and delay the onset of AD (12,14). The aim of this research is to examine the evidence of potential neuroprotective effects of walnut consumption at self-selected levels on cognitive function in a representative sample of the adult population in the United States (US).…”

Polyphenol Ellagic Acid-Targeting To Brain: A Hidden Treasure

“…The brains of individuals with AD had increasedlevels of lipid peroxidation products such as 4-hydroxynonenalor 2-propenal, and enhanced lipid peroxidationwas also detected in the cerebrospinal fluid and plasma ofindividuals with AD [14,15] . In addition, oxidativedamage to membrane proteins, cellular mitochondrial and nuclear DNA isalso an important event in AD pathology [1] . The first neurotransmitter defect discovered in AD involved acetylcholine [16] (Francis et al, 1999).…”

“…Walnuts (Juglans regia L.) are an excellent source of α-linolenic acid (plant-based omega-3 fatty acid) and have a high content of antioxidants such as flavonoids, phenolic acid (ellagic acid), melatonin, gamma tocopherol and selenium. Walnutextract can counteract Aβ-induced oxidative stress and associated cell death [1] . EA inhibit β-secretase (BACE1) in vitro, thus inhibiting Aβ-fibrillation [73] .…”

“…Alzheimer's disease is a severe neurodegenerativedisease that gradually results in loss of memory andimpairment of cognitive functions in the elderly [1] . According to Alzheimer's Association, Alzheimer's disease (AD) is affecting an estimated 5.2 million Americans in 2014, including 5.0 million over age 65 [2] .…”