Theanine is a very important relaxing component unique to green tea. The caffeine contained in green tea is widely known for its awakening property. The combination of these substances makes the green tea even more powerful.
Green tea comes from the leaves of the Camellia sinesis plant (tea tree), which naturally contains caffeine. If we compare the caffeine content of green tea with caffeine in coffee, we can conclude that green tea has a significantly less amount per cup.
Green tea contains 15 - 60 mg caffeine per 8 ounce cup, average 30.
One cup of green tea provides 10-40 mg of polyphenols (antioxidants).
A cup of tea contains lesser amounts of caffeine than coffee, but the tannin concentration is much higher. Tannins have anticancer and carcinogenic properties. Also, tannins are known to decrease the digestibility of proteins.
Green tea contains large amounts of catechin tannins (10-25%). Catechin is a powerful, water soluable polyphenol and antioxidant that is easily oxidized.
Green tea contains four main catechin substances: EC, ECg, EGC and EGCg, which are called catechin. The most powerful of these catechins is Epigallocatechin gallate (EGCG). EGCG as an antioxidant is about 25 to 100 times more potent than vitamins C and E.
Catechin is tannin peculiar to green tea. Other teas contain less catechins because its fermentation process reduces catechins in teas.
Green tea is manufactured from fresh and unfermented tea leaves. It is less processed than other teas and it is lightly oxidized, (the oxidation of catechins is minimal) and because of that its leaves have their own special health elements and less caffeine.
The amount of catechin and caffeine in green tea depends of many factors.
The season in which the leaves of tea tree are picked is vital; usually harvesters will pick leaves in the springtime, during morning hours. The catechin content tends to increase as the season progresses. Spring teas contains 12-13% catechin (13-17% as tannin) while summer tea contains 13-14% (17-21% as tannin).
Also, younger leaves include more tannins than mature ones. First spring leaves contain 14%, second 13%, third 12%, and fourth 12%.
If leaves are covered during growth (get less sunshine) they will contain less catechin and astringency (10% as tannin).
Catechins in green tea are very strong antioxidants and have far-reaching positive effects on the entire body.
Note: All figures are approximate; this site does not provide medical advice, diagnosis or treatment.