A team of researchers found that green and black tea inhibit the activity of certain enzymes in the brain that are associated with Alzheimer’s disease. The findings may lead to the development of a new treatment for a disease that affects an estimated ten million people worldwide.
The research team from Newcastle University’s Medicinal Plant Research Centre investigated the properties of coffee and green and black tea in a series of scientific experiments. They found that both green and black tea inhibited the activity of the enzyme acetylcholinesterase (AChE), which breaks down the chemical messenger or neurotransmitter, acetylcholine. Alzheimer’s is characterized by a drop in acetylcholine. Coffee had no significant effect. Green tea and black tea also hinder butyrylcholinesterase (BuChE), which has been discovered in protein deposits found on the brain of Alzheimer’s patients. Green tea went one step further – it inhibited beta-secretase, which plays a role in the protein deposits. Scientists also found that it continued to have its inhibitive effect for a week, whereas black tea’s enzyme-inhibiting properties lasted for only one day.
Alzheimer’s drugs currently on the market also hinder the activity of these enzymes; however, many of them, such as donepezil, have unpleasant side effects and the medical profession is keen to find alternatives.
Lead researcher Dr Ed Okello said: “Although there is no cure for Alzheimer’s, tea could potentially be another weapon in the armoury which is used to treat this disease and slow down its development. It would be wonderful if our work could help improve the quality of life for millions of sufferers and their carers.
University of Newcastle upon Tyne, Oct 25, 2004