Green tea (Camellia sinensis L. kuntze) comes from evergreen tree family Theaceae, is native to south-eastern Asia. The leaves of the plant are used to prepare tea, a very popular beverage that is consumed by more than two-thirds of the world population. By simple process of heating in water, which inactivate the enzyme polyphenol oxidase and thus preserves leaf polyphenols from oxidation. The main bioactive compounds occurring in the leaves are flavonoids such as catechins, of which the most abundant is epigallocatechin-3-gallate (EGCG). In traditional Chinese medicine that leaves of green tea have been used for centuries to treat asthma, bronchial spasms, and vascular diseases. Pharmacological studies also suggest that green tea reduces the risk of cardiovascular diseases and cancer, exhibits anti-hypertension, antibacterial, antiviral and anti-inflammatory effects, improves the regulation of body weight, increases the mineral density of bones, and exerts anti-UV and neuro-protective actions.