Active compounds in tea

The plant Camellia sinensis yields a variety of tea. There are four main types of tea produced from this same plant, depending on how the tea leaves are processed. These teas are white, green, Oolong, and black tea.

The chemical composition of tea includes polyphenols, amino acids, vitamins, proteins, carbohydrates, trace elements. In addition, alkaloids such as caffeine (1,3,7 trimethylxanthine), theobromine and theophylline are also natural compounds present in tea.

Research has shown that the main components of green tea that are associated with health benefits are the catechins. The four main catechins found in green tea are: (−)-epicatechin (EC), (−)-epicatechin-3-gallate (ECG), (−)-epigallocatechin (EGC), and (−)-epigallocatechin-3-gallate (EGCG). Of these four, EGCG is present in the largest quantity, and so has been used in much of the research.

Black tea has far fewer active catechins than green tea. Tea contains many amino acids, but theanine, specific to the tea plant, is the most abundant, accounting for 50% of the total amino acids. Amino acid degradation is involved in the biogenesis of the tea aroma.

Tea also contains carbohydrates, vitamins E, K, A, low levels of B vitamins and vitamin C (in green tea only). Tea also provides useful amounts of potassium, manganese and fluoride ions to the diet.
Active compounds in tea