Tea plant belongs to the Theaceae family (Cameliaceae) and appears in two varieties: var. sinensis (Chinese tea) and var. assamica (Indian tea, Assam tea). It is grown, among others, in China, India, Indonesia and Ceylon. In China, the tradition of tea growing and its preparation dates back to 3000 BC. Green tea is a beverage prepared only from Chinese tea leaves, which has not been subjected to fermentation. The infusion of green tea is rich in many valuable components, e.g. polyphenols, tannins, alkaloids, vitamins (A, B, C, E), and microelements such as calcium, potassium, copper, zinc, manganese and fluorine.
H. Strzelecka, J.Kowalski, Encyklopedia zielarstwa i ziołolecznictwa, wyd. PWN, Warszawa 2000, s. 183-184