Consumption of high dose green tea Polyphenol decreases Hepatic levels of CYP 3A iso-enzyme

According to a recent research article on European Journal of Pharmaceutical Sciences, high doses of green tea can significantly diminish the level of hepatic CYP 3A iso-enzyme of the Cytochrome P450 enzyme system in mice. This finding is of clinical importance for substrates(drugs) that are solely or primarily metabolised by the CYP 3A enzyme.

In this study, the long-term safety of high-dose GP was assessed from a pharmacokinetic point of view by focusing on the drug-metabolizing enzyme, cytochrome P450 (CYP). Mice were fed a diet containing 3% GP for 4 weeks, and the CYP expression levels and activity were determined. The GP-treated group showed a significant decrease in the hepatic CYP3A and an increase in the hepatic CYP2C expression compared with the control group. CYP1A, CYP2D, and CYP2E expression were not different between the GP-treated and the control groups. In the small intestine, there were no differences in the CYP3A protein levels between the groups. The increase in the plasma triazolam concentration in the GP-treated group was observed. Although no changes were found in the hepatic CYP3A levels in mice receiving a diet containing 0.1% GP for 4 weeks, a significant decrease was seen in the hepatic CYP3A level in mice receiving a diet containing 3% GP for only 1 week. This study revealed that the intake of a high-dose GP results in a liver-specific decrease in the CYP3A expression level. The results also indicated that the effects of GP on CYP3A were not observed following the intake of a low-dose GP. In the future, caution should be taken in cases when functional foods containing a high-dose GP are concomitantly consumed with a CYP3A substrate drug.