Thyme (Thymus vulgaris L.) leaves and its constituents increase the activities of xenobiotic-metabolizing enzymes in mouse liver

J Med Food. Summer 2005;8(2):184-9. doi: 10.1089/jmf.2005.8.184.


The effects of thyme (Thymus vulgaris L.) leaves and its phenolic compounds, thymol and carvacrol, on the activities of xenobiotic-metabolizing enzymes, i.e., phase I enzymes such as 7-ethoxycoumarin O-deethylase (ECOD) and phase II enzymes such as glutathione S-transferase (GST) and quinone reductase (QR), were investigated. Mice were fed with a diet containing thyme (0.5% or 2.0%) or treated orally with thymol (50-200 mg/kg) or carvacrol (50-200 mg/kg) once a day for 7 successive days, and then the enzyme activities in the livers were analyzed. Dietary administration of 2% thyme caused slightly but significantly higher ECOD, GST, and QR activities by 1.1-1.4-fold. Thymol (200 mg/kg) treatment resulted in significantly higher ECOD, GST, and QR activities by 1.3-1.9-fold, and carvacrol (200 mg/kg) treatment caused significantly higher ECOD, GST, and QR activities by 1.3-1.7-fold. Thymol-treated animals had significantly higher protein levels of GST alpha and GST micro, and carvacrol-treated animals had significantly higher levels of GST micro. These results imply that thyme contains bifunctional inducers (i.e., substances capable of inducing both phase I and phase II enzymes) and that thymol and carvacrol may account for the effects of thyme.

MeSH terms

  • 7-Alkoxycoumarin O-Dealkylase / metabolism
  • Animals
  • Blotting, Western
  • Cymenes
  • Dose-Response Relationship, Drug
  • Electrophoresis, Polyacrylamide Gel
  • Glutathione Transferase / metabolism
  • Liver / drug effects
  • Liver / enzymology*
  • Male
  • Mice
  • Monoterpenes / pharmacology*
  • NAD(P)H Dehydrogenase (Quinone) / metabolism
  • Organ Size / drug effects
  • Plant Extracts / pharmacology*
  • Plant Leaves
  • Random Allocation
  • Thymol / pharmacology*
  • Thymus Plant / chemistry*
  • Xenobiotics / metabolism*


  • Cymenes
  • Monoterpenes
  • Plant Extracts
  • Xenobiotics
  • Thymol
  • carvacrol
  • 7-Alkoxycoumarin O-Dealkylase
  • NAD(P)H Dehydrogenase (Quinone)
  • Glutathione Transferase