Effect of herbal teas on hepatic drug metabolizing enzymes in rats

Abstract

We have investigated the effect of herbal teas (peppermint, chamomile and dandelion) on the activity of hepatic phase I and phase II metabolizing enzymes using rat liver microsomes. Female Wistar rats were divided into six groups (n = 5 each). Three groups had free access to a tea solution (2%) while the control group had water. Two groups received either green tea extract (0.1%) or aqueous caffeine solution (0.0625%). After four weeks of pretreatment, different cytochrome P450 (CYP) isoforms and phase II enzyme activities were determined by incubation of liver microsomes or cytosol with appropriate substrates. Activity of CYP1A2 in the liver microsomes of rats receiving dandelion, peppermint or chamomile tea was significantly decreased (P < 0.05) to 15%, 24% and 39% of the control value, respectively. CYP1A2 activity was significantly increased by pretreatment with caffeine solution. No alterations were observed in the activities of CYP2D and CYP3A in any group of the pretreated rats. Activity of CYP2E in rats receiving dandelion or peppermint tea was significantly lower than in the control group, 48% and 60% of the control, respectively. There was a dramatic increase (244% of control) in the activity of phase II detoxifying enzyme UDP-glucuronosyl transferase in the dandelion tea-pretreated group. There was no change in the activity of glutathione-S-transferase. The results suggested that, like green and black teas, certain herbal teas can cause modulation of phase I and phase II drug metabolizing enzymes.

Cancer chemoprevention and chemotherapy: Dietary polyphenols and signalling pathways

“…Similarly, drinks rich in phenolic compounds, tea and mate increased QR activity in the Hepa1c1c7 cells [57] and in general, phenolic compounds, such as quercetin, hesperidin, disomin, chlorogenic acid, etc., prevented GSH depletion and ROS formation after an oxidative injury caused by different prooxidants [45,59]. Consequently, tea also showed in vitro a protective effect on rat hepatic extracts, which was associated with a reduced activity of CYP2E and an increased activity of phase II detoxifying enzyme UDPGT, suggesting that tea can regulate phase I and phase II drug metabolizing enzymes, although GST activity was unaffected [56].…”

Women’s perception of safety and utilization of herbal remedies during pregnancy in a local government area in Nigeria

“…However, herbal remedy may contain substances that may be harmful to the fetus or the baby. Remedies have also been described to have the possibility of interacting with prescribed drugs and anaesthetic agents [12][13][14][15] or cause fetal malformations [16,17] . In fact some authorities have cautioned against the use of almost all herbal remedies during pregnancy [18] .…”

Risks and benefits of commonly used herbal medicines in Mexico

“…This type of interaction, just like those produced between two or more medicines, can produce pharmacokinetic interactions if they affect the processes of absorption, distribution, metabolism and excretion, or exert pharmacodynamic interactions. There are numerous examples in the literature of herbal medicine-drug pharmacokinetic interactions (Maniacal and Wanwimolruk, 2001;Unger and Frank, 2004). One of the most important types of interactions occurs between herbal products and drug metabolizing enzyme systems, particularly the cytochrome P450 (CYP) isoenzymes.…”

“…Other preliminary research indicates that peppermint leaf tea might lower testosterone levels and decrease spermatogenesis in male animals, as well as increase FSH and LH levels. Preliminary evidence suggests that peppermint oil might interact with cytochrome P450 isoforms (CYP1A2, CYP2C19, CYP2C9, and CYP3A4) and therefore might modify levels of drugs metabolized by those cytochromes (Maniacal and Wanwimolruk, 2001;Unger and Frank, 2004).…”

“…These results suggest that dandilion may have clinical implications on the dosing of ciprofloxacin or other quinolone antibiotics. There is preliminary evidence in animals that dandelion might inhibit cytochrome P450 1A2 (CYP1A2) and it might induce UDP-glucuronosyltransferase, a phase II enzyme (Maniacal and Wanwimolruk, 2001;Unger and Frank, 2004). Theoretically, dandelion might increase the clearance of drugs that are UDPglucuronosyltransferase substrates.…”