Tea (Camellia sinensis) originated in southern China and is consumed by over two thirds
of the world population. Tea has an attractive aroma, good taste, and health-promoting
effects, and these benefits combine to make it one of the most popular drinks in the
world. Tea was used by the Chinese as a medicinal drink as early as 3000 B.C., and as a
beverage by the end of the sixth century. Because tea is an excellent beverage and has an
effective pharmaceutical activity, tea plants are now widely cultivated in Southeast Asia
including mainland China, India, Japan, Taiwan, Sri Lanka, and Indonesia and in a
number of countries in central Africa. Hundreds of teas are now produced and are
generally classified into three categories: nonfermented green tea, partially fermented
oolong and paochong teas, and fully fermented black and puerh tea. The composition of
tea varies in a complex manner, according to species, season, age of the leaf, climate, and
horticultural practices [1].
