" The Ancient Chinese held tea in high regard for its medicinal and rejuvenating properties, they prized the teas that grew high on the mountains, and it should be brewed with pure, clean, mountain spring water" 
                                      Wisdom of the Old Chinese Tea Master

Chemical Components of Tea

Polyphenols are a combination of several groups of phenols, organic molecules present in plants. In the plant of tea, they are found in the catechins, which epigallocatechin gallate  (EGCG) is the main component. Polyphenols give tea astringency, strength, and thickness.

Alkaloids are organic molecules that contain nitrogen and are found in amino acids. The main one in tea is caffeine.

Caffeine or L-Theine are the same alkaloids, the caffeine in tea is different to the caffeine in coffee because it forms different bonds with other substances like tannins, which make the caffeine in tea attenuated. Tennis prevents caffeine from being released rapidly, therefore, last longer and is more regular.

In Tea, caffeine stimulates the central nervous system and the cardiovascular system enlarging the diameter of the vessels in the cerebral cortex.

In Coffee caffeine has a direct effect on the blood circulation through the coronary system, stimulating and accelerating the heart rate.   

Tea is more of a stimulant than an excitant, sharpens the mind, increases concentration, eliminates fatigue and enhances intellectual acuity.