Results of laboratory tests by a team from the University of Newcastle upon Tyne found that green and black tea inhibit the activity of certain enzymes in the brain which are associated with memory.
The findings, which are published in the academic journal, Phytotherapy Research, may lead to the development of a new treatment for a form of dementia which affects an estimated ten million people worldwide, Alzheimer's Disease.
For their experiment, 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. Black tea traditional English breakfast tea is derived from the same plant as green tea, Camellia sinensis, but has a different taste and appearance because it is fermented.
They found that both green and black tea inhibited the activity of enzymes associated with the development of Alzheimer's Disease, but coffee had no significant effect.
Both teas inhibited the activity of the enzyme acetylcholinesterase (AChE), which breaks down the chemical messenger or neurotransmitter, acetylcholine. Alzheimer's is characterised by a drop in acetylcholine.
Green tea and black tea also hinder the activity of the enzyme butyrylcholinesterase (BuChE), which has been discovered in protein deposits which are found on the brain of patients with Alzheimer's.
Green tea went one step further in that it obstructed the activity of beta-secretase, which plays a role in the production of protein deposits in the brain which are associated with Alzheimer's disease. 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.
There is no cure for Alzheimer's but it is possible to slow the development of the disease. Dru
Contact: Dr Ed J Okello
University of Newcastle upon Tyne