Tea is a popular drink from ancient to modern China. Tea tasting is a significant part of Chinese culture, which is also introduced to other Asian countries. Tealeaves can be categorized according to the extent of fermentation into three types: 1. Non-fermented, such as green tea; 2. Semi-fermented, such as Pouchong; 3.
Fermented, such as black tea and Pu-erh tea.
Non-fermented tea can keep active ingredients in tealeaves. Therefore, green tea that falls in this category is containing most of the ingredients in the tealeaves. On top of caffeine, vitamin, microelement, and mineral substance, the most important ingredient for our health is tea polyphenols. Tea polyphenols is a generic term for all the polyphenols in tealeaves, including at least 7 kinds of catechins, which is proven to be good for our health. It helps slow aging, prevent tooth decay, cancer, bacterium, virus, and protect our cardiovascular system.
Main Ingredients of Catechins
Phenolic compounds and their derivatives in green tea are called polyphenols, which compose 10-30% of the tea leaves. The most useful ingredient of the phenolic compounds is catechins, making up 70% of the total amount of phenolic compounds. Catechins refer to two groups: free forms such as catechin, epicatechin (EC), epigallocatechin (EGC), and esterification of gallic acid such as epicatechin gallate (ECG) and epigallocatechin gallate (EGCG). EGCG is a major polyphenolic compound in green leaves.
The unique chemical structure of catechins helps to clear free radicals in the body, which are produced by metabolism, pollution from outside world, electromagnetic waves, drug abuse, as well as other negative properties that gradually accumulate in the body. Free radicals include superoxide anion, hydroxyl radicals, and hydrogen peroxide. Catalase, vitamin C, E, β-carotene, and catechins absorbed from food can remove excessive free radicals in the cells. Free radicals and reactive oxygen species are very reactive with a pair of unpaired electrons, as they can destroy cells and body tissues, cause chronic diseases and cancer, and accelerate aging. Many diseases, including cerebral apoplexy, arteriosclerosis, cancer, and Alzheimer’s disease are also believed to be relevant to excessive free radicals in the body. Surveys indicate that catechins can effectively remove free radicals and reactive oxygen species from your body. And the efficiency depends on the amount of OH in catechins, which means, the more OHs, the higher efficiency. Because EGCG has 8 OHs, the amount of EGCG is often used by researchers to judge the quality of catechins.
Effects of Catechins