Flavonoids are a specific class of polyphenols present in fruits, vegetables, tea, grape juice and red wine. Over 4,000 different flavonoids have been identified. Flavonoids possess strong antioxidant properties and may protect cells and tissue against free radicals. Flavonoids may also offer non-antioxidant properties (such as regulating complex cell processes) associated with a variety of health benefits. During the meeting of the American Dietetic Association in May 2005, tea was identified as the most significant source of flavonoids in the US diet.
Catechins are the primary flavonoids produced by the Camellia sinensis plant. Because green and white tealeaves undergo minimal processing, they retain the leaf’s naturally high level of catechins. EGCG (Epigallocatechin Gallate) is the main catechin in green tea and appears to be the most powerful—with antioxidant activity about 25-100 times more potent than vitamins C and E. Catechins are believed to fight aging and cancer and are responsible for the slightly astringent, bitter flavor often associated with green tea.
When green tealeaves are oxidized to create black tea, the leaf undergoes an enzymatic reaction, which changes the color of the leaves and results in the polymerization of catechins into theaflavins and thearubigins. Theaflavins and thearubigins are believed to prevent heart disease and promote cardiovascular health. Because it is partially oxidized, oolong tea contains both green tea’s catechins and black tea’s theaflavins and thearubigins.
Theanine is a rare amino acid (found almost exclusively in high quality tea--especially white and green teas) that produces a calming, mood-enhancing effect in the brain, acting as a natural anti-depressant and stress reliever. Theanine is highly concentrated in the young tealeaves early in the growing season, and is converted into catechins as the leaf matures. Therefore, tea that comes from early harvests and teas that are shade-grown contain the highest levels of theanine because the extra production of catechin is restricted. (Early-harvest and shade-grown teas also contain a high percentage of catechins because the leaves are young and nutrient-dense). Theanine provides an elegant, gentle, sweet taste to the tealeaves.