Studies have tied green tea to a reduced risk of Alzheimer's, but the mechanisms underlying this link have been unclear. Now, a new study reveals how a compound in the popular beverage disrupts the formation of toxic plaques that contribute to the disease.
Researchers found that the green tea polyphenol epigallocatechin gallate (EGCG) stops the formation of beta-amyloid plaques — a hallmark of Alzheimer's disease — by interfering with the function of beta-amyloid oligomers.
Lead study author Giuseppe Melacini, of the Departments of Chemistry and Chemical Biology at McMaster University in Canada, and colleagues recently reported their findings in the Journal of the American Chemical Society.
Alzheimer's disease is a progressive neurodegenerative condition characterized by a decline in memory and thinking, as well as behavioral problems.
It is estimated that almost 50 million people worldwide are living with the disease. By 2050, this number is expected to rise to 131.5 million.
The precise causes of Alzheimer's disease remain unclear, but it is believed that beta-amyloid plays a key role. This "sticky" protein can clump together, forming plaques that disrupt communication between nerve cells.
The new study from Melacini and his team sheds light on how EGCG could help to prevent beta-amyloid plaque formation, bringing us closer to much-needed prevention strategies for Alzheimer's disease.
EGCG 'remodels' beta-amyloid oligomers
The researchers came to their findings by using nuclear magnetic resonance to get an in-depth look at how EGCG might affect the formation of beta-amyloid plaques.
The team explains that beta-amyloid monomers — which are tiny binding molecules — form beta-amyloid oligomers. Over time, these oligomers can stick together and form toxic beta-amyloid plaques.
In their analysis, Melacini and colleagues found that EGCG "remodels" beta-amyloid oligomers, which stops them from creating harmful plaques.
"At the molecular level," explains Melacini, "we believe EGCG coats toxic oligomers and changes their ability to grow and interact with healthy cells."
These findings not only support previous
Based on their findings, the researchers suggest that extracts from green tea could be used in the prevention of Alzheimer's disease.
"We all know that currently there is no cure for Alzheimer's once symptoms emerge, so our best hope is early intervention. That could mean using green tea extracts or their derivatives early on, say 15 to 25 years before any symptoms ever set in."
The team notes, however, that it is difficult to deliver EGCG directly to the brain, so future research will need to focus on finding ways to modify the compound and overcome this problem.