Several studies have already linked green tea consumption to a reduced risk of developing Alzheimer’s disease, but the mechanisms underlying this link were unclear. Now, research led by the department of chemistry and chemical biology at McMaster University (Canada) reveals how: through a compound in green tea that alters the formation of toxic plaques that contribute to disease.
Alzheimer’s, a progressive neurodegenerative disease characterized by a decline in memory and general cognitive functioning, affects almost 50 million people worldwide and it is estimated that by 2050 there could be more than 130 million people.
The exact causes of this disease are unclear , but beta-amyloid is believed to play a major role, as this sticky protein can clump together, forming plaques that disrupt communication between neurons.
The researchers found that epigallocatechin gallate (EGCG), a polyphenol in green tea, stops the formation of beta-amyloid plaques, a hallmark of Alzheimer’s disease, by interfering with the function of oligomers (proteins composed of more than a polypeptide chain) beta-amyloid.
The power of EGCG
The study, published in the Journal of the American Chemical Society, sheds light on how EGCG could help prevent beta-amyloid plaque formation, bringing us closer to much-needed prevention strategies for Alzheimer’s disease.
The researchers reached their conclusions by using nuclear magnetic resonance imaging to get an in-depth look at how this green tea polyphenol (EGCG) might affect beta-amyloid plaque formation. The scientists found that EGCG “remodels” beta-amyloid oligomers – which can bind together and form toxic beta-amyloid plaques – preventing them from creating these harmful plaques.
“At the molecular level, we believe that EGCG covers toxic oligomers and changes their ability to grow and interact with healthy cells ,” explains Giuseppe Melacini, leader of the work.
These findings not only support previous studies suggesting that EGCG polyphenol may help prevent beta-amyloid plaque formation, but also shed light on the mechanisms underlying this association.
Based on their findings, the researchers suggest that green tea extracts could be used in the prevention of Alzheimer’s disease:
“We all know that there is currently no cure for Alzheimer’s disease once symptoms arise, 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 symptoms appear, “says Melacini.
The authors note, however, that it is difficult to deliver EGCG polyphenol directly to the brain, so future research will need to focus on finding ways to modify this compound to overcome this problem. Be that as it may, this is great news.
Reference: Rashik Ahmed et al. Molecular Mechanism for the (-) – Epigallocatechin Gallate-Induced Toxic to Nontoxic Remodeling of Aβ Oligomers, Journal of the American Chemical Society (2017). DOI: 10.1021 / jacs.7b05012
