Anti-Cancer Compound in Green Tea Identified by Patricia Reaney, Health - Reuters
LONDON (Reuters) - Spanish and British scientists have
discovered how green tea helps to prevent certain types of
Researchers at the University of Murcia in Spain (UMU) 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,
"This is the first time, to our knowledge, a known target for an
anti-cancer drug has been identified as being inhibited by EGCG,"
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 is probably just one of a number of
anti-cancer mechanisms in green tea.
"We have identified this enzyme in tumour cells that EGCG
targets and understand how it stops this enzyme from making DNA.
This means we may be able to develop new anti-cancer drugs based on
the structure of the EGCG molecule," Thorneley explained.
The scientists decided to look at ECGC after they realized its
structure was similar to a cancer drug called methotrexate.
"We discovered that EGCG can kill cancer cells in the same way
as methotrexate," Dr Jose Neptuno Rodriguez-Lopez, of UMU, a joint
author of the research published in the journal Cancer
EGCG binds strongly to DHFR, which is essential in both healthy
and cancerous cells. But it does not bind as tightly as
methotrexate, so its side effects on healthy cells could be less
severe than those of the drug.
Thorneley said EGCG could be a lead compound for new anti-cancer
The findings could also explain why women who drink large
amounts of green tea around the time they conceive and early in
their pregnancy may have an increased risk of having a child with
spina bifida or other neural tube disorders.
Women are advised to take supplements of folic acid because it
protects against spina bifida. But large amounts of green tea could
decrease the effectiveness of folic acid.
"This enzyme, (DHFR), is the one folic acid supplements are
given for. Folic acid deficiency leads to neural tube development
defects," Thorneley added.
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