Chemoprevention, in recent years, has emerged as a potential strategy for prevention and control of cancer. Chemoprevention is a means by which the use of naturally occurring and/or synthetic compounds completely prevents, blocks or reverses the occurrence of the disease. Prevention of cancer through dietary intervention has received considerable attention in the recent past and is viewed as a potential strategy for the management of cancer (1, 2). Ever since the finding from this laboratory in 1988 and 1989 about anticarcinogenic and antimutagenic activity of polyphenolic agents present in green tea (3-5), prevention of cancer through the consumption of this widely used beverage is receiving increasing attention. Green tea, derived from the plant dCamellia sinensis (an evergreen shrub of the theaceae family), contains many polyphenolic antioxidants and is one of the most popularly consumed beverages in the world. It is important to emphasize that for many generations in some parts of the world, tea consumption has been considered to possess health-promoting potential (6). Extensive laboratory research and the epidemiological observations published in recent years have revealed that the polyphenolic compound present in green tea may prevent a variety of cancer types. The effectiveness of green tea against cancer has been attributed to the presence of the polyphenolic antioxidants as its major constituents. The major polyphenolic antioxidants present in green tea are (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin-3-gallate, and (-)-epigallocatechin-3-gallate.
History and Consumption of Tea
Thousands of years ago, the plant Camellia sinensis was originally discovered and grown in Southeast Asia. According to Chinese mythology, in 2737 BC, emperor Shen Nung discovered tea for the first time. It rapidly spread worldwide and is presently cultivated in at least 30 countries around the world. Tea, consumed worldwide at greatly varying levels, is next to water with a per capita human consumption of approximately 120 ml/day worldwide (7).
