Garlic Extract Exhibits Antiamyloidogenic Activity on Amyloid-beta Fibrillogenesis: Relevance to Alzheimer's Disease

Alzheimer's disease is characterized pathologically by the deposition of amyloid plaques. Fibrillar A beta is the principal component of amyloid plaques in the brain of A beta patients. The prevention of A beta aggregation or dissolution of fibrillar A beta has clinical significance. The present communication examined in vitro the antiamyloidogenic properties of garlic extract. The effects of aqueous garlic extract (both fresh and boiled) on A beta aggregation and defibrillation were studied by thioflavin-T based fluorescence assay. transmission electron microscopy and SDS-polyacrylamide gel electrophoresis. The aqueous fresh garlic extract not only inhibited A beta fibril formation in a concentration and time dependent manner but was also able to defibrillate A beta preformed fibrils. The maximum defibrillization was observed after 2-3 days of incubation. The boiled aqueous garlic extract also retained its antiamyloidogenic activity. This indicated that antiamyloidogenic activity of garlic extract is non-enzymatic, i.e. proteases present in garlic did not degrade A beta in solution. However, the fibril degrading ability of boiled garlic extract was significantly lost. The findings suggest that consumption of garlic may lead to inhibition of A beta aggregation in human brain. Copyright (c) 2008 John Wiley & Sons. Ltd.