London: Drinking tea regularly could help improve memory, a research by British scientists from the University of Newcastle suggests.

The scientists found that green and black tea inhibit the activity of certain enzymes in the brain that are associated with memory.

The findings, published in the journal Phytotherapy Research, may lead to the development of a treatment for Alzheimer's disease, which affects an estimated ten million people worldwide.

The team investigated the properties of coffee and green and black tea.

Black tea, traditional English breakfast tea, is derived from the same plant as green tea, 'Camellia sinensis', but has a different taste and appearance as 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 found on the brains of patients with Alzheimer's.

Green tea went one step further by obstructing the activity of beta-secretase, which plays a role in the production of protein deposits in the brains that are associated with Alzheimer's.

Scientists also found that it continued to have its inhibitive effect for a week, whereas black tea's enzyme-inhibiting properties lasted for only a day. Drugs currently in the market hinder the activity of AChE, but they have unpleasant side effects.

The researchers are seeking funding to carry out further tests on green tea, which they hope will include clinical trials.

Their aim is to work towards the development of a medicinal tea aimed at Alzheimer's sufferers.