Green tea is made from the leaves from Camellia sinensis that have undergone minimal oxidation during processing. The compound in question, extracted from the tea, is called epigallocatechin-3-gallate (EGCG). It is the primary polyphenol found in the beverage.
Earlier studies had shown that EGCG was able to kill oral cancer cells without destroying normal cells. However, scientists were unable to explain why. A new study provides a possible explanation. Here it has been found that EGCG triggers a process in the mitochondria that leads to cell death. Mitochondria are the powerhouses of cells. They generate most of the cell’s supply of adenosine triphosphate (ATP), which is used as a source of chemical energy.
It would appear that EGCG causes the formation of reactive oxygen species in cancer cells, which damages the mitochondria, and the mitochondria responds by making more reactive oxygen species which eventually triggers the death of the cancer cells.
For the study, scientists examined normal human oral cells and human oral cancer cells and exposed them to EGCG, at concentrations typically found in the saliva after chewing green-tea chewing gum. The cells were examined for oxidative stress and signs of antioxidant response. In seeing a clear effect, where cancer cells were destroyed, it was later found that EGCG targets a protein called sirtuin 3 within the cancer cells.
Up until now, there has been no conclusive evidence that green tea helps to prevent or treat cancer in people. It should be noted that the next phase of the research is to look at animals. Any effect in people has yet to be proven and the research is a long way away from making or substantiating any such claims as “green tea cures cancer.”
The findings have been published in the journal Molecular Nutrition and Food Research. The research paper is titled “Differential prooxidative effects of the green tea polyphenol, (-)-epigallocatechin-3-gallate, in normal and oral cancer cells are related to differences in sirtuin 3 signaling.”
