Since ancient times, tea has been a popular beverage. As part of the traditional culture, it was spread to East Asia and other countries. Manufactured tea can be divided into the following three categories according to the degree of fermentation: a. non-fermented tea, such as green tea; b. semi-fermented tea, such as bagged tea; c. fully-fermented tea, such as Pu’er tea and black tea.
Introduction of Catechins
In addition to caffeine, vitamins, trace elements and minerals, compounds in tea also include tea polyphenols. As a general term, tea polyphenols contain at least seven important catechin substances, and they have various benefits to human health ranging from antioxidant, anti-aging, anti-caries, anti-cancer, anti-bacteria, anti-virus, cardiovascular protection and other closely related effects in addition to weight loss effects.
Catechin Teas – Green Tea
Green tea contains polyphenols called phenolic compounds and their derivatives called flavanols, which account for 10-30% of tea ingredients. The most useful polyphenols in humans are catechins, according to many scientists and physicians, which is why teas such as green and puer have been widely known for so many health benefits. Catechins in fact can be divided into the following two categories: free patterns and esterified gallic acid. The former include catechin, epicatechin (EC) and epigallocatechin (EGC); the latter include epicatechin gallate (ECG)and Epigallocatechin gallate (EGCG). Found in major green leaves, EGCG has a higher level than the former.
The unique chemical structure of catechins can help the body remove free radicals from the normal metabolism of external environmental pollution, electromagnetic waves, drug abuse, and accumulation in body. Radicals include superoxide anion, hydroxyl radicals and hydrogen peroxide, and unwanted radicals can be eradicated within cells via catalase, or by food intake of vitamin C, E beta, carotene or catechin, etc. Free radicals and reactive oxygen species are very active because with a pair of unpaired electrons that damage cells or tissue, they can cause chronic, accelerated aging or cancer. It is generally believed that many diseases, such as stroke, atherosclerosis, cancer and Alzheimer’s, are related to the fact that free radicals could not be effectively removed. Studies have shown that catechins can effectively remove free radicals and reactive oxygen molecules in the body, and the efficiency of removal depends on the structure of catechin hydroxyl (the number of OH); the more the hydroxyl, the higher the efficiency. There are eight hydroxyl groups in EGCG, and the quality of EGCG catechins are often evaluated according to the level of EGCG.
The Effects of Catechins in Tea