Green tea chemical could be used for treatment of brain disorders, say scientists

Scientists at Boston Biomedical Research Institute (BBRI) and the University of Pennsylvania have found that combining two chemicals, one of which is the green tea component EGCG, can prevent and destroy a variety of protein structures known as amyloids, the primary culprits in Alzheimer's, Huntington's and Parkinson's diseases. Their study, published in Nature Chemical Biology, may ultimately contribute to future therapies for these diseases.

"These findings are significant because it is the first time a combination of specific chemicals has successfully destroyed diverse forms of amyloids at the same time," said Martin Duennwald of BBRI, who co-led the study with James Shorter of the University of Pennsylvania School of Medicine.

Amyloid plaques are tightly packed sheets of proteins that infiltrate the brain. These plaques, which are stable and seemingly impenetrable, fill nerve cells or wrap around brain tissues and eventually (as in the case of Alzheimer's) suffocate vital neurons or brain cells, causing loss of memory, language, motor function and eventually premature death.

To date, researchers have had no success in destroying plaques in the human brain and only minimal success in the laboratory. One reason for these difficulties is the stability and complexity of amyloids.

Duennwald experienced success in previous studies when he exposed amyloids in living yeast cells to EGCG. Furthermore, he and his collaborators also found that DAPH-12 inhibits amyloid production in yeast.

In the new study, the team looked in more detail at the impact of these two chemicals on the production of different amyloids produced by the yeast amyloid protein known as PSI+.

The team's first step was to expose two different amyloid structures produced by yeast (e.g. a weak version and a strong version) to EGCG. They found that the EGCG effectively dissolved the amyloids in the weaker version but not the stronger amyloids, some of which transformed to even stronger versions after exposure to EGCG.

The team then exposed the yeast amyloid structures to a combination of EGCG and DAPH-12 and found that all of the amyloid structures broke apart and dissolved.

The next step will be to explore the mechanism and potency of such a therapy for the treatment of diverse neurodegenerative diseases.

"Our findings are certainly preliminary and we need further work fully to comprehend the effects of EGCG in combination with other chemicals on amyloids. Yet we see our study as a very exciting initial step towards combinatorial therapies for the treatment of amyloid-based diseases," said Duennwald.