Spanish and British scientists have discovered how green tea helps to prevent certain types of cancer.

Researchers at the University of Murcia in Spain and the John Innes Center (JIC) in Norwich, England have shown that a compound called EGCG in green tea prevents cancer cells from growing by binding to a specific enzyme.

"We have shown for the first time that EGCG, which is present in green tea at relatively high concentrations, inhibits the enzyme dihydrofolate reductase (DHFR), which is a recognized, established target for anti-cancer drugs," Professor Roger Thorneley, of JIC, said.

"This is the first time, to our knowledge, a known target for an anti-cancer drug has been identified as being inhibited by EGCG," he said.

Green tea has about five times as much EGCG as regular tea, studies have shown.

It decreased rates of certain cancers but scientists were not sure what compounds were involved or how they worked. Nor had they determined how much green tea a person would have to drink to have a beneficial effect, he said.

Thorneley said EGCG was probably just one of a number of anti-cancer mechanisms in green tea.

(China Daily/Agencies March 17, 2005)