Walnut Extract Inhibits the Fibrillization of Amyloid Beta-Protein, and also Defibrillizes its Preformed Fibrils
Abstract:Fibrillar amyloid beta-protein (Aβ) is the principal component of amyloid plaques in the brains of patients with Alzheimer's disease. We have studied the effect of walnut extract on Aß fibrillization by Thioflavin T fluorescence spectroscopy and electron microscopy. The walnut extract not only inhibited Aß fibril formation in a concentration and time- dependent manner but it was also able to defibrillize Aβ preformed fibrils. Over 90% inhibition of Aβ fibrillization was observed with 5 ml of methanolic extract of walnut (MEOW) both after 2 and 3 days of incubation. The maximum defibrillization (91.6%) was observed when preformed Aβ fibrils were incubated with 10 ml of MEOW for 2 days. These results suggest that walnuts may reduce the risk or delay the onset of Alzheimer's disease by maintaining Aß in the soluble form. Further studies showed that anti-amyloidogenic compound in walnut is an organic compound of molecular weight less than 10 kDa, which is neither a lipid nor a protein. Chloroform extract of walnut had no effect on Aβ fibrillization while MEOW and its 10 kDa filtrate inhibited Aβ fibrillization equally. It is proposed that polyphenolic compounds (such as flavonoids) present in walnuts may be responsible for its anti-amyloidogenic activity.
Document Type: Review Article
Affiliations: NYS Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA.
Publication date: August 1, 2004
More about this publication?
- Current Alzheimer Research publishes peer-reviewed frontier review and research articles on all areas of Alzheimer's disease. This multidisciplinary journal will help in understanding the neurobiology, genetics, pathogenesis, and treatment strategies of Alzheimer's disease. The journal publishes objective reviews written by experts and leaders actively engaged in research using cellular, molecular, and animal models. The journal also covers original articles on recent research in fast emerging areas of molecular diagnostics, brain imaging, drug development and discovery, and clinical aspects of Alzheimer's disease. Manuscripts are encouraged that relate to the synergistic mechanism of Alzheimer's disease with other dementia and neurodegenerative disorders. Book reviews, meeting reports and letters-to-the-editor are also published. The journal is essential reading for researchers, educators and physicians with interest in age-related dementia and Alzheimer's disease. Current Alzheimer Research provides a comprehensive 'bird's-eye view' of the current state of Alzheimer's research for neuroscientists, clinicians, health science planners, granting, caregivers and families of this devastating disease.