What is the relationship between EGCG and other chemical names, such as polyphenols, flavonoids (flavanoids), catechins, and antioxidants?
EGCG is a specific chemical and can be defined and measured in weight. It is one of the four catechins in green tea, being the most abundant and most active antioxidant of the four. Therefore, it is chosen as the surrogate yardstick to measure the antioxidant level in tea drinks and in tea leaves. EGCG is the most active antioxidant of the tea catechins, which are chemically members of the flavonoid category, which are in turn polyphenols. Not all flavonoids and not all polyphenols have antioxidant properties. After the tea catechins have lost their antioxidant activities, they can still be referred to as flavonoids or polyphenols. Unlike EGCG, the amount of flavonoids or polyphenols in a tea beverage does not reflect its antioxidant strength. How are green tea leaves graded? Traditionally, green teas are graded by aroma, taste and appearance of the tea leaves. In general, the tips or the young leaves of plants harvested in early spring are the highest grades and have been valued at ab
