Previous studies have found that the major polyphenol in green tea extracts, epigallocatechin gallate (EGCG), has chemopreventive effects on cancers affecting a number of organs in the digestive tract.
The team from the Harvard Medical School reported that EGCG inhibits the growth and reproduction of cancer cells (SEG-1 and BIC-1)associated with Barrett's oesophagus. Barrett's oesophagus is a condition caused by stomach acid creeping back up from the stomach. The acid damage causes the cells lining the oesophagus to change and raises the risk of oesophageal cancer by 30 to 40 times.
The researchers concluded that exposure to EGCG induces apoptosis, or programmed cell death, and results in increased levels of the proteins caspase-3 and cleaved poly-ADP-ribose polymerase (PARP, known to play a role in DNA damage repair.
In the study (abstract 103982), the adenocarcinoma cells were treated with different concentrations of EGCG and monitored for cell growth, method of cell death and changes in apoptotic protein levels. Treatment of cells with EGCG inhibited cell growth and caused signs of early apoptosis at 24 hours. Further studies found that EGCG significantly increased levels of active caspase-3 and cleaved PARP proteins.
"Research suggests that drinking green tea may be both a valuable chemopreventive therapy as well as a treatment for oesophageal adenocarcinoma," said Howard Chang, an investigator of the study.
In the UK 7,200 people a year are diagnosed with cancer of the oesophagus, up 65 per cent in the last 30 years. A recent study, also presented at Digestive Disease Week, has linked this increase to growing consumption of fizzy drinks.