Piperine, a major constituent of black pepper, inhibits human P-glycoprotein and CYP3A4.
Dietary constituents (e.g., in grapefruit juice; NaCl) and phytochemicals (e.g., St. John's wort) are important agents modifying drug metabolism and transport and thereby contribute to interindividual variability in drug disposition. Most of these drug-food interactions are due to induction or inhibition of P-glycoprotein and/or CYP3A4. Preliminary data indicate that piperine, a major component of black pepper, inhibits drug-metabolizing enzymes in rodents and increases plasma concentrations of several drugs, including P-glycoprotein substrates (phenytoin and rifampin) in humans. However, there are no direct data whether piperine is an inhibitor of human P-glycoprotein and/or CYP3A4. We therefore investigated the influence of piperine on P-glycoprotein-mediated, polarized transport of digoxin and cyclosporine in monolayers of Caco-2 cells. Moreover, by using human liver microsomes we determined the effect of piperine on CYP3A4-mediated formation of the verapamil metabolites D-617 and norverapamil. Piperine inhibited digoxin and cyclosporine A transport in Caco-2 cells with IC(50) values of 15.5 and 74.1 microM, respectively. CYP3A4-catalyzed formation of D-617 and norverapamil was inhibited in a mixed fashion, with K(i) values of 36 +/- 8 (liver 1)/49 +/- 6 (liver 2) and 44 +/- 10 (liver 1)/77 +/- 10 microM (liver 2), respectively. In summary, we showed that piperine inhibits both the drug transporter P-glycoprotein and the major drug-metabolizing enzyme CYP3A4. Because both proteins are expressed in enterocytes and hepatocytes and contribute to a major extent to first-pass elimination of many drugs, our data indicate that dietary piperine could affect plasma concentrations of P-glycoprotein and CYP3A4 substrates in humans, in particular if these drugs are administered orally.
Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Auerbachstrasse 112, D-70376 Stuttgart, Germany.
Rajinder K
RK
Bhardwaj
Hartmut
H
Glaeser
Laurent
L
Becquemont
Ulrich
U
Klotz
Suresh K
SK
Gupta
Martin F
MF
Fromm
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors*; D000470:Alkaloids; D052117:Benzodioxoles; D001692:Biological Transport / Q000187:drug effects; D003110:Colonic Neoplasms; D016572:Cyclosporine / Q000493:pharmacokinetics; D051544:Cytochrome P-450 CYP3A; D065607:Cytochrome P-450 Enzyme Inhibitors; D004077:Digoxin / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors*; D010880:Piperidines / Q000494:pharmacology*; D053284:Polyunsaturated Alkamides; D014407:Tumor Cells, Cultured
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000470:Alkaloids; D052117:Benzodioxoles; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D010880:Piperidines; D053284:Polyunsaturated Alkamides; D004077:Digoxin; D016572:Cyclosporine; D006899:Mixed Function Oxygenases; C104464:CYP3A protein, human; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; C008922:piperine