During the last ten years, more than 300 medical studies have described various health benefits of tea (Camellia sinensis) and there is growing evidence that tea is even more healthful than previously believed, and that both processed (oolong and black) and unprocessed (white and green) tea are beneficial. Two studies, one in the U.S. and one in Europe, released in spring 2007 revealed that Green Tea has even more stellar benefits, particularly for leukemia, cancer, and most recently, in combination with other elements to fight prostate cancer.
All true tea contains seven of the eight essential human amino acids, the “good guys” that repair tissues, build cells, and attack bacteria and viruses. Tea also has an amino acid exclusive to it called theanine which helps in the biosynthesis of such antioxidants as catechins and polyphenols.
Of all these “good guys” the polyphenol called ECGC is the most powerful and its presence is often five times greater in Green Tea than in oolong or black primarily because it is not oxidized, leaving its enzymes relatively unaffected by heat and other processing techniques.
Researchers study how ECGC, which is epigallocatechin 3-gallate, can be harnessed to fight a variety of diseases including CLL, a virulent form of leukemia, and a variety of cancers in which ECGC works to reduce the size and number of tumors, slow the growth of known cancer cells.
One study revealed how a combination of green tea and a COX-2 inhibitor can work better in the fight against cancer than independently. Researchers from the University of Wisconsin-Madison demonstrated that low doses of the COX-2 inhibitor celecoxib, administered with ECGC, slows the growth of human prostate cancer. Their experiments, performed in cell cultures and in a mouse model for the disease, showed that, “celecoxib and Green Tea have a synergistic effect — each triggering cellular pathways that, combined, are more powerful than either agent alone,” said Hasan Mukhtar, Ph.D., professor of dermatology at the University of Wisconsin and member of Wisconsin’s Paul Carbone Comprehensive Cancer Center. This development may lead to a preventative treatment for prostate cancer. In 2004, Mukhtar and his colleagues demonstrated that Green Tea polyphenol EGCG has cancer-fighting abilities of its own and can inhibit experimental tumor growth in animals.
Scientists in Madrid and Great Britain reported that they now know why Green Tea’s EGCG works in fighting cancer. British researcher Roger Thorneley said that studies have shown for the first time that ECGC, which is present in Green Tea five times as much as other teas, inhibits the enzyme dihydrofolate reductase (DHFR), which is a recognized, established target for anti-cancer drugs. He added that identifying this enzyme in tumor cells has led to their understanding of how EGCG binds with a specific enzyme which then limits the growth of cancer cells. Its chemical structure is very similar to the chemotherapy drug methotrexate. This new understanding paves the way for more effective cancer fighting drug based on the structure of the ECGC molecule. Researchers are from University of Murcia in Spain and at the John Innes in Norwich, England.