Drinking tea appears to affect the brain in a similar way as drugs prescribed for Alzheimer's disease, UK researchers report. The team, based at Newcastle University's Medicinal Plant Research Centre, investigated the properties of green and black tea, as well as coffee, in a series of laboratory experiments. Their study was published in the August 2004 edition of Phytotherapy Research.
The results showed that both green and black tea inhibited the activity of enzymes associated with the development of Alzheimer's disease. Coffee, however, had no significant effect.
The teas inhibited the activity of acetylcholinesterase -- the same mechanism of action used by drugs such as Novartis' Exelon and Pfizer's Aricept. The teas also hindered the activity of the butyrylcholinesterase, which has been found in senile plaques in the brains of Alzheimer's disease patients. Green tea obstructed the activity of beta-secretase, which also plays a role in the production of senile plaques, and is the focus of research by companies such as Ireland's Elan.
"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," lead researcher, Dr. Ed Okello, said. However, he added that there is no published evidence showing that rates of Alzheimer's disease are any lower in tea-loving countries such as Britain, China and Japan.
The researchers are seeking funds to find out which components of green tea inhibit the activity of the three enzymes and hope ultimately to develop a medicinal tea for Alzheimer's disease patients.
Phytotherapy Research, August 2004.