Clinical and pre-clinical pharmacokinetics of green tea polyphenols.
Tea consumption has been suggested to have beneficial effects for human health, especially in cancer prevention. At present, epidemiological evidence of the protective effect of tea consumption against the development of human cancer is not conclusive. Interpretation of epidemiological data and extrapolation of rodent data to humans are generally hampered by inadequate information on the bioavailability and pharmacokinetics of tea constituents. We have performed studies to determine the pharmacokinetics of green tea in humans after single and multiple oral dose administration of tea polyphenols and the contribution of hepatic first-pass elimination to the low oral bioavailability of green tea catechins in animals.