Green Tea Alters Cancerous Reactions

Green Tea Alters Cancerous Reactions

ROCHESTER, N.Y.--Green tea may be able to reduce the risk ofcancer in smokers by shutting down a key molecule's actions, which increase therisk of tobacco-related cancer, according to researchers at the University ofRochester Medical Center. Their in vitro research, published in the July 21issue of Chemical Research in Toxicology (16, 7:865-72, 2003) (www.acs.org),demonstrated green tea's epigallocatechingallate (EGCG) and epigallocatechin(EGC) were able to decrease activity of the aryl hydrocarbon (AH) receptor.

Because the AH receptor is known to activate harmful genes, researchersinvestigated the effects of green tea constituents on it. The in vitro researchdemonstrated EGCG and EGC shut down the receptor, which may demonstrate adifferent mechanism of action for green tea's anti-cancer benefits; green tea isalready known as an antioxidant, which may also give it anti-cancer properties.

"It's likely that the compounds in green tea act through many differentpathways," said Thomas Gasiewicz, Ph.D., director of Rochester'sEnvironmental Health Science Center and a study author. "Green tea may workdifferently than we thought to exert its anti-cancer activity."

Researchers pointed out that green tea's inhibitory effects were present whenlevels of EGCG and EGC reached those typical in a cup of green tea. However,because metabolism is going to affect the constituents' activity, the in vitroresearch may not be indicative of green tea's activity after ingestion.

"Right now we don't know if drinking the amount of green tea that aperson normally drinks would make a difference, but the work is giving usinsight into how the proteins [EGCG and EGC] work," said Christine Palermo,a graduate student that worked with Gasiewicz. "There are a lot ofdifferences between various kinds of green tea, so a lot more research isneeded."