Flavonoids are a group of plant metabolites thought to provide health benefits through cell signaling pathways and antioxidant effects. These molecules are found in a variety of fruits and vegetables. The abundance of flavonoids coupled with their low toxicity relative to other plant compounds means they can be ingested in large quantities by animals, including humans. Examples of foods that are rich in flavonoids include onions, parsley, blueberries, bananas, dark chocolate and red wine.
Quercetin and epicatechin are examples of flavonoids, essential pigments found in many fruits and vegetables.
Quercetin is the aglycone form of flavonoid glycosides such as rutin and quercitrin which are found in buckwheat, citrus fruit and onions. Quercetin is thought to have anti-inflammatory and antioxidant effects and to protect against some forms of illness such as cancer. However, the clinical evidence to support this claim is not yet available, despite promising initial research findings. Quercetin is found in various types of fruits, vegetables, teas, wine and many other food items.
Catechins are important flavonoids abundant in the leaves of the tea plant.* Examples include epicatechin, epicatechin gallate, and epigallocatechin gallate. When oolong tea or black tea is prepared, the leaves are allowed to oxidize. This causes conversion of some or all of the catechins to larger molecules and reduces the flavonoid content. White tea is tea that has undergone even less processing than green tea and therefore provides the highest catechin content.
*All teas from the Camellia plant are rich in polyphenols, antioxidants that detoxify cell-damaging free radicals in the body. Tea has about eight to 10 times the polyphenols found in fruits and vegetables, and the longer you steep the tea, the more flavonoids you'll get in your brew. Some believe white tea can reduce cholesterol and blood pressure and acts as a blood thinner and contibutes to bone density, all because of the falconoids (there are thousands of falconoids, and it’s a great word for Scrabble).
DIY decaf white tea (because it can have a lot of caffeine): "Just brew a cup as normal, leaving the leaves in the hot water for about 30 seconds. Then drain the tea leaves and rebrew... The caffeine content is almost completely lost with the first brewing (in fact, just as much caffeine is equal to any commercial decaf!)." From a non-working website.Green tea extract and cognitive functions