A green tea extract is a herbal derivative from green tea leaves (Camellia sinensis). Containing antioxidant ingredients - mainly green tea catechins (GTC) - green tea and its derivatives are sometimes used as dietary supplements and in alternative medicine.
Green tea extracts have been used in traditional Chinese and Indian medicine for a variety of uses.
Components include three kinds of flavonoids, known as kaempferol, quercetin, and myricetin. A remarkably higher content of myricetin is detected in tea and its extracts than in many other plants, and this high concentration of myricetin may have some implications with the bioactivity of tea and its extracts.
Green tea extract is approximately twice more antioxidant-active than Vitamin C. The main attribution is supposed to be EGCG. [5] One study by the Drug and Food department of Iran in 2008 compared antioxidant properties of various green tea compounds with those of vitamin C and vitamin E: the study concluded that green tea extracts -for a total of approximately 68 mg of combined phenols, flavonoids and anthocyanidin present from 1g of a sample of "Chinas green tea" leaves, the grade yielding the highest content of bioactive chemicals- had the equivalent antioxidant power found in 50 mg-275 mg of vitamin C and 156 mg-813 mg of vitamin E
The biochemical properties of green tea extracts can be generally divided into four aspects - antioxidant, anticarcinogen, anti-inflammatory, and anti-radiation.
