Green Tea

Green tea has been a medicinal potion for thousands of years. Laden with plant chemicals called flavonoids known for their powerful antioxidant abilities, green tea is touted to protect against two of the biggest of human scourges—coronary disease and cancer. But just how green tea works its wonders in the prevention or treatment of individual disease remains a mystery. Thomas Gasiewicz, researcher in the Department of Environmental Medicine at the University of Rochester Medical Center, presented evidence for some of its magic at an international conference on diet and cancer held in Washington, D.C., today. His laboratory demonstrated that the prime antioxidant component of green tea, which is in the family of plant chemicals called catechins—or epigallocatechin-3-gallate (EGCG) to be precise—zooms in on a key target in the cancer cell. And the target is a big one: a normal stress protein, known as heat shock protein 90 (HSP90). Heat shock or stress proteins are critical to survival of all cells, cancerous or otherwise. Stress proteins abound in both plants and animals. Think of them as protectors that chaperone the thousands of worker-bee proteins that interact in and on the surface of our cells in the course of any one cell's life. Growth, performance, communication, you name it, and some form of HSP is a key player. When cells are threatened by a treacherous environment such as heat (from which we get the name HSP), proteins curl up and then clump up. We now know it also happens with damaging cold, low oxygen, or poisons. Heat shock protein protectors quickly rev up and come to the rescue to both repair injured proteins and to carry the irreversibly damaged ones to a disposal dump for an out-of-the-way burial so new ones can take their place. Cancer hijacks the stress protein network in its efforts to overtake the body. Cancer cells are fast growing and on the march wherever they set up shop—breast, prostate, colon, bone marrow. And in that superstressed state...