Urinary detection of hydroxycinnamates and flavonoids in humans after high dietary intake of fruit.

The determination of the abilities of flavonoids, hydroxycinnamates and phenolics to scavenge free radicals in vitro suggests potent combined antioxidant activities of fruits, vegetables, beverages and grains. However, the key question of uptake in humans has only recently been approached consistently. The study described here demonstrates the uptake of hydroxycinnamates, for the first time, and other phenolic components, applying an HPLC method for their detection in the urine of subjects consuming levels of specific fruit equivalent to an approximate intake of 25 mg flavonol glycosides.