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
- Prevent hypertension and protects the vascellum. Catechins inhibit the angiotensin converting enzyme in the kidney cells from working, which stops the angiotensin II being produced and therefore lower blood pressure and protect the vascellum.
- Prevents cancer and tumors. The activation of oncogene is related to the living environment and diets. According to the Research Report on Public Health, drinking green tea can reduce the risk of prostate cancer and mouth cancer. Another report says that it has great effect on the high-risk-group of liver and gastrointestinal tumor if they drink 10 cups of green tea a day.
- Antibacterial: Catechins inhibit the growth of and kill pathogenic bacteria and other virus. Tests prove that catechins can kill staphylococcus, botulin in the, and also able to fight against the toxin produced by cholera bacteria and botulin.
- Prevents gastric ulcer. The helicobacter pylori enzyme in stomach secretes ammonia that prevents bacterium from being killed by gastric acid. Catechins stop the secretion of ammonia and further prevent gastric ulcer.
- Prevents tooth decay. Tooth decay bacterium secrete ferment that will attach to the tooth surface and cause cavities. Catechins can stop the tooth decay bacterium from producing ferment and thus prevent periodontosis and tooth decay.
- Catechins inhibit the rise of blood pressure.