New research may provide an explanation for the anti-inflammatory properties often accredited to green tea, reports Reuters Health.
Studies on animals and other laboratory research has already found that the polyphenols in green tea act as anti-inflammatory agents, but the understanding behind the results has so far been limited.
Researchers in Ohio, US have found that one type of polyphenol known as epigallocatechin-3-gallate, or EGCG, inhibits the expression of the interleukin-8 gene--a key gene involved in the inflammatory response.
"We found that this compound reduced the expression of this gene significantly in a culture cell model," said study author Dr. Hector Wong of Cincinnati Children's Hospital Medical Center in Ohio.
"As we increased the dose, the effect was more profound," he told Reuters Health.
In a study by the Society of Critical Care Medicine, the researchers looked at human lung cells that were cultured in a lab dish and treated with a protein called tumour necrosis factor, which typically triggers the expression of IL-8, resulting in the production of the IL-8 protein. In the body, the IL-8 protein attracts white blood cells to a particular site, resulting in tissue inflammation, Wong said.
But when the investigators introduced EGCG in their experiment, they found that it blocked the expression of IL-8. The higher the dose, the greater the effect.
"This compound can short circuit this cascade that leads to inflammation," Wong said. While the evidence for green tea alone treating inflammation is not yet conclusive, Wong suggested that the positive results so far would merit further study.
Consumption of green tea in Asia is thought to contribute to improvements in diseases often characterized by inflammation, such as colitis and arthritis. Green tea may also play a role in fighting cancer and heart disease.