4.1 Chemistry
The subject of so much discussion, green tea is made from the prepared leaves and leaf buds of the tea plant, botanical name Camellia Sinensis part of the Theaceae family.
It is not fermented like most of other tea. Leaves are steamed to reduce bacterial and enzymatic activity, dried and then grounded into a fine powder.
Green tea is prepared in such a way as to preclude the oxidation of green leaf polyphenols. The enzymatic processes will start oxidation very soon after plucking the leaves. Fresh tea leaf is unusually rich in the flavanol group of polyphenols known as catechins which may constitute up to 30% of the dry leaf weight. Caffeine is present at an average level of 3% along with very small amounts of the other common methylxanthines, theobromine and theophylline. Green tea composition is very similar to that of the fresh leaf except for a few catalyzed enzymatic changes which occur extremely rapidly following plucking. The amino acid theanine (5-N-ethylglutamine) is also unique to tea.
4.2 Research
Scientific studies have indicated a strong correlation between the use of green tea and alleviation of hepatitis in patients. Studies also indicated an inhibition of tooth decay..
Scientists confirmed that that tea drinkers as a group experience lesser chances of hardening in the arteries when compared to people who regularly drink only coffee as a daily beverage. One reason suggested for these observations is that the caffeine in coffee may be chemically bound to some heavy oils; these often tend to elevate the total levels of serum cholesterol somewhat. This same effect on the body is not induced by either the dark or the green teas. Cholesterol levels may in fact be cut down significantly by the caffeine content present in both tea varieties in the large number of patients. At the same time, other benefits accrue to tea drinkers on the whole as the polyphenols present in the tea can act in concert with the body’s supply of vitamins C and P; this combination effect will on the whole help in strengthening the walls of the blood vessels.
As an herbal measure, tea is helpful in the treatment of various infections affecting the digestive tract of patients. Tea is also used for the treatment of various eye problems; it is used in the treatment of hemorrhoids, to treat physical tiredness and fatigue, and to bring down fever in patients.
