Green tea leaves, scientifically known as Camellia sinensis are the prime ingredients of antioxidants called the green tea catechins (GTC). Green tea and its herbal derivates like green tea extracts are most commonly employed by people because of the myriad health benefits they offer. They contain four major epicatechin derivatives known as epigallocatechin (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC) and epicatechin (EC). Green tea extracts have been divided into four major types which include:

Strong infusions: In order to obtain this extract, the green tea leaves are soaked in alcohol solution with aspect content being 2% w/w.

Dry extracts: After the strong infusions undergo a concentration of 40 – 50% in solid form, the catechin content gets raised above 25% w/w. These solids are then sprayed and dehydrated as extract powder with water content as low as 5%. These are then converted into various forms such as tablets, capsules and other dry mixes.

Soft extracts: These are made by strong infusions further being concentrated to 20-25% with catechin content being about 20%.

Partially purified extracts: These are more purified forms of green tea obtained through various techniques like column chromatography, solvent extraction, membrane extraction etc.

Nutritional Analysis& Health Benefits :

Green tea extracts are known to contain the cardinal anti-oxidative constituents 20 times more than those contained in vitamin C and E. The polyphenols contained in green tea extracts have the ability to combat free radicals in the human body. Investigations have revealed these tea extracts to have high content of superoxide dimutase and glutathione dimutase which aid in inhibitory effect of GTC against rancidification. Besides, acting as a strong antioxidant agent, their biochemical properties have been further categorized as anti-carcinogenic, anti-inflammatory and anti-radiation. Experiments carried on nude mice clearly reveal green tea's inhibitory function to fight prostatic carcinoma to great extent. The maltose content has been observed to lower after drinking green tea which is indeed suited to be used for oral hygiene maintenance. Radioactive isotope experiments carried on white mice also showed green tea's effectiveness in fighting radiations. The green tea catechins (GTC) are seen to be quite unstable in alkaline solutions as compared to their excellent ability in acidic mixtures.

References :

T. Johnson & G. Williamson, Phytochemical functional foods, Cambridge , UK : Woodhead Publishing, 2003, pp. 135-145.

Q.Y. Zhu, Antioxidative activities of green tea catechins, Hong Kong: The Chinese University of Hong Kong ( Hong Kong ), 1999, p. III.

F. Murray, 100 super supplements for a longer life, Los Angeles : CA McGraw-Hill Professional, 2000, pp. 181–182.

Y.S. Zhen, Z.M. Chen, S.J. Cheng & M.L. Chen, Tea: bioactivity and therapeutic potential, London , UK : New York Taylor & Francis, 2002, pp. 121–225.