Here's how green tea may help to fight cancer
The Straits Times Interactive
The leaves are rich in epigallocatechin gallate, a compound that limits the activity
of tumour cells, say American researchers
WASHINGTON -- Green tea contains a substance that can kill tumour cells, which may explain
why the drink, popular in Asia, seems to protect people from cancer, researchers say.
Green tea is much richer in the compound than other kinds of tea, a husband-and-wife team at
Purdue University found.
"Our research shows that green tea leaves are rich in this anti-cancer compound, with
concentrations high enough to induce anti-cancer effects in the body," Professor Dorothy
Morre, a professor of foods and nutrition, said in a statement.
She and her husband James Morre, a chemist and pharmacologist, had heard reports of green
tea's purported effects and set out to see if there was a mechanism.
Speaking at a meeting this week of the American Society of Cell Biology in San
Francisco, they said they found that green tea affects an enzyme known as NOX.
"Normal cells express the NOX enzyme only when they are dividing in response to growth-
hormone signals," Prof Dorothy Morre said. "In contrast, cancer cells have somehow gained
the ability to express NOX activity at all times."
This tumour-associated NOX activity is called tNOX. The Morres set out to see if there
was something in tea that affects NOX. They found epigallocatechin gallate (EGCg),
which interfered with tNOX but not with normal NOX.
"This is one of the first studies to link the EGCg in green tea directly to anti-cancer
activity," she said. The EGCg limits the activity of breast-cancer tumour cells grown
in the laboratory, but does not seem to affect normal, healthy breast cells, the Morres reported.
Now tests are needed to see if EGCg is active in the bodies of people who drink green tea.
Green tea and black tea come from the same bush in the camellia family. But black tea has
been allowed to ferment, which may interfere with compounds such as EGCg. --Reuters
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