I often get boxes of green tea as a welcoming gift from visiting scientists. Occasionally, I sample these fine teas, however, a recent study makes me realize that perhaps I should be drinking more of it.
MADC affiliate Dr. Mi Hee Lim and her colleagues recently published in the Proceedings of the National Academy of Sciences, that a flavonoid found in green tea, called ECGC, binds and changes the property of beta-amyloid, a toxic protein that accumulates in the brains of individuals with Alzheimer’s disease.
The question that guided Dr. Lim’s research was “Why does green tea extract have anti-amyloid properties?”
To answer her question, she used an array of biochemical and cell biological approaches. The outcome of Dr. Lim’s studies show that ECGC can bind beta-amyloid monomers (a protein by itself) and dimers (two proteins bound together), particularly when calcium or zinc is present. When ECGC and beta-amyloid bind together, beta-amyloid is less likely to form into the large, ordered fibrils that eventually comprise the brain plaques found in Alzheimer’s disease. Beta-amyloid can take on many shapes, but ECGC seems to force the beta-amyloid into a single shape. More importantly, ECGC was able to reduce the toxicity of beta-amyloid in cells, suggesting that this single shape, or structure, may be less toxic than other forms of beta-amyloid.
So, what does this mean for our understanding of Alzheimer’s and the discovery of better therapies?
First, green tea extract by itself is probably not potent enough to represent a potential therapeutic compound. You should still go ahead and drink it, but know that the levels of ECGC in your body will be far lower, and less powerful, than the levels used in this study. Second, the new knowledge about how flavonoids bind beta-amyloid and alter its properties represents a key starting point toward the development of similar compounds that do the same thing, just in a stronger way. Finally, Dr. Lim’s discovery that this compound forces beta-amyloid into a distinct, simpler structure sheds light on the complexity of beta-amyloid behavior, reminding us that we still have much more to learn about beta-amyloid and its effects on our brain.
Visit the MADC website to find other research studies the Center is working on.
The Michigan Alzheimer’s Disease Center (MADC) was established at the University of Michigan Health System, through affiliation with the Department of Neurology and aims to conduct and promote research on Alzheimer’s disease and related disorders; ensure state-of-the-art care for individuals experiencing cognitive impairment or dementia; and enhance the public’s and health professionals’ understanding of dementia through education and outreach efforts. The infrastructure of the Center stems from a 20 year history as an NIH-funded Alzheimer’s Disease Research Center.
For more than 160 years, the University of Michigan Health System has been a national leader in advanced patient care, innovative research to improve human health and comprehensive education of physicians and medical scientists. The three U-M hospitals have been recognized numerous times for excellence in patient care, including 18 years on the U.S. News & World Report honor roll of “America’s Best Hospitals.”