Green tea and Alzheimer’s disease

Knowing when to hold them, and when to fold them

You’ve probably heard about EGCG (or epi-gallo-catechin-3-gallate) before. It’s the chemical that gives green tea it’s impressive health benefits. In fact, a recent study in Egypt found that EGCG can cause remission of cancer (see “Egyptian researchers cure cancer with the help of two herbal remedies” in the September 2012 issue of Insiders’ Cures). Now another new study shows EGCG may also help fight Alzheimer’s dementia.

Researchers found EGCG prevents the abnormal folding of specific proteins in the brain.1 The grouping of these proteins, called “metal-associated amyloids,” is thought to play a role in the development of Alzheimer’s dementia and other degenerative diseases of the nervous system.

All proteins are made up of chains of amino acids. In a longer protein, the amino acids in the chain interact with each other so the protein is folded into a certain shape.

The folded shape of a protein is critical to how it works in the body. Consider the protein hemoglobin, for example. It has the important role in binding the metal iron, and carrying oxygen in the blood. That function, the ability to carry iron, is based on its folding, and resulting shape (not just its chemical composition). In fact, Linus Pauling received his first Nobel Prize for discovering how protein folding occurs to create the correct shape of hemoglobin.

When genetic variations of the hemoglobin molecule substitute specific amino acids in the chain, it causes the protein to fold into different shapes. These changes cause diseases such as sickle cell anemia, Thalassemia, and others.

So, as I’ve said before, just understanding a molecule’s chemical content is not enough. You have to understand its folding and shape to understand its role in the body. And it’s not enough to measure the quantity of biochemical in the blood; we also need to know their quality—literally what shape they are in.

In this study, EGCG prevented formation of amyloid groupings and even broke down existing groups in proteins that contain metals (specifically copper, iron, and zinc). As with the folding of the hemoglobin protein, the folding of these amyloid proteins to contain metals appears critical to whether or not they cause disease.

The researchers pointed out that many studies are investigating small molecules and metal-associated amyloid proteins in Alzheimer’s dementia—but most are looking from a limited perspective. And most are also overlooking the dementia-fighting abilities of natural products like green tea.

By remembering some biochemistry 101, it looks like these chemists, biochemists, and biophysicists have found a new and promising approach.

Sources:

1. “Insights into antiamyloidogenic properties of the green tea extract (−)-epigallocatechin-3-gallate toward metal-associated amyloid-β species,” PNAS 2013; published online ahead of print Feb 20, 2013 (doi: 10.1073/pnas.1220326110)


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