The effects of green tea polyphenols on drug metabolism

Abstract

Tea catechins may bind to certain drugs to affect their absorption and bioactivities. Tea catechins may inhibit the activities of drug-metabolizing enzymes and drug transporters or affect the expression of these proteins, either upregulation or downregulation. Although these effects have been demonstrated in studies in vitro and in animal models, such effects have only been observed in limited cases in humans at common doses of human tea consumption. The ingestion of tea catechins from dietary supplements, which could be in large bullet doses, may produce more profound effects on drug metabolism, and such effects with drugs need to be further investigated.

Rosuvastatin pharmacokinetics and pharmacogenetics in Caucasian and Asian subjects residing in the United States

“…While there are dietary constituents that may play a role in modulating drug metabolizing enzymes and transporters (e.g. green tea, curcumin, capsaicin, garlic) [24], herbal supplements in general were restricted during this study, which was not designed to look at individual dietary elements.…”

Effects of stachyose on absorption and transportation of tea catechins in mice: possible role of Phase II metabolic enzymes and efflux transporters inhibition by stachyose

“…3a–d), suggesting that pre-treatment of stachyose did not change Phase II biotransformation of TC in the liver. Most drugs undergo an initial Phase I metabolism, generally catalyzed by CYPs, to form more water-soluble metabolites, and the metabolites are then catalyzed by UGT and SULT (32). However, previous studies suggest that catechins are not likely to undergo Phase I metabolism by CYPs due to their molecular structure (3, 32).…”

“…Most drugs undergo an initial Phase I metabolism, generally catalyzed by CYPs, to form more water-soluble metabolites, and the metabolites are then catalyzed by UGT and SULT (32). However, previous studies suggest that catechins are not likely to undergo Phase I metabolism by CYPs due to their molecular structure (3, 32). Although catechins are not the substrate of CYPs, it is well known that TC can exhibit the strong inhibition of CYPs, and this effect may decrease related nutrients metabolism (32).…”

Effect of oral administration of green tea extract in various dosage schemes on oxidative stress status of mice in vivo

“…obesity (2). Ample evidence of their benefi cial eff ects on human health has led to the increasing popularity of food supplements, which contain catechins in high doses (3).…”

“…Ample evidence of their benefi cial eff ects on human health has led to the increasing popularity of food supplements, which contain catechins in high doses (3). It is therefore essential to keep in mind the possible undesired eff ects the catechins -such as toxicity (4), pro-oxidative eff ects (4) or alteration of drug-metabolizing enzymes and transporters (2,5). On the other hand, the modulation of detoxifying enzymes by catechins can contribute to chemoprotection and antioxidant defense of organisms (6).…”