Student or educator? Sign up with your school email and get 6 months of Pro free.
Cited by 214Pharmacogenetics and Drug MetabolismCurcumin's Biomedical ApplicationsDrug Transport and Resistance Mechanisms

The DOI matches its Crossref record; 40 of the 42 references it cites were found in a registry or an index; none of the 26 sources its claims cite is checked for support yet.

Curcuminoids Inhibit Multiple Human Cytochromes P450, UDP-Glucuronosyltransferase, and Sulfotransferase Enzymes, whereas Piperine Is a Relatively Selective CYP3A4 Inhibitor

Open access
Volak, Laurie P., Ghirmai, Senait, Cashman, John R., Court, Michael H.·2008·Drug Metabolism and Disposition

Abstract

Curcuminoid extract and piperine are being evaluated for beneficial effects in Alzheimer's disease, among other intractable disorders. Consequently, we studied the potential for herb-drug interactions involving cytochrome P450 (P450), UDP-glucuronosyltransferase (UGT), and sulfotransferase (SULT) enzymes. The curcuminoid extract inhibited SULT > CYP2C19 > CYP2B6 > UGT > CYP2C9 > CYP3A activities with IC(50) values ranging from 0.99 +/- 0.04 to 25.3 +/- 1.3 microM, whereas CYP2D6, CYP1A2, and CYP2E1 activities were less affected (IC(50) values > 60 microM). Inhibition of CYP3A activity by curcuminoid extract was consistent with competitive inhibition (K(i) = 11.0 +/- 1.3 microM), whereas inhibition of both CYP2C9 and CYP2C19 activities were consistent with mixed competitive-noncompetitive inhibition (10.6 +/- 1.1 and 7.8 +/- 0.9 microM, respectively). Piperine was a relatively selective noncompetitive inhibitor of CYP3A (IC(50) 5.5 +/- 0.7 microM, K(i) = 5.4 +/- 0.3 microM) with less effect on other enzymes evaluated (IC(50) > 29 microM). Curcuminoid extract and piperine inhibited recombinant CYP3A4 much more potently (by >5-fold) than CYP3A5. Pure synthetic curcuminoids (curcumin, demethoxycurcumin, and bisdemethoxycurcumin) were also evaluated for their effects on CYP3A, CYP2C9, UGT, and SULT activities. All three curcuminoids had similar effects on CYP3A, UGT, and SULT activity, but demethoxycurcumin (IC(50) = 8.8 +/- 1.2 microM) was more active against CYP2C9 than either curcumin or bisdemethoxycurcumin (IC(50) > 50 microM). Based on these data and expected tissue concentrations of inhibitors, we predict that a p.o. administered curcuminoid/piperine combination is most likely to inhibit CYP3A, CYP2C9, UGT, and SULT metabolism within the intestinal mucosa.

Overview

CoChat Summary

TL;DR

Curcuminoid extract inhibited multiple human CYP, UGT, and SULT enzymes in vitro, with SULT and CYP2C19 among the most sensitive, while piperine was a relatively selective CYP3A inhibitor. The authors predict that orally administered curcuminoid/piperine combinations are most likely to inhibit CYP3A, CYP2C9, UGT, and SULT metabolism in the intestinal mucosa.

Key findings

  • Curcuminoid extract inhibited SULT > CYP2C19 > CYP2B6 > UGT > CYP2C9 > CYP3A activities, with IC50 values from 0.99 ± 0.04 to 25.3 ± 1.3 μM; CYP2D6, CYP1A2, and CYP2E1 were less affected (IC50 >60 μM). Specific values included SULT in human liver cytosol 0.99 ± 0.04 μM, CYP2C19 7.4 ± 1.2 μM, CYP2B6 9.4 ± 1.9 μM, CYP2C9 13.5 ± 1.4 μM, and CYP3A 25.3 ± 1.3 μM.
  • Piperine was a relatively selective noncompetitive CYP3A inhibitor (IC50 5.5 ± 0.7 μM; Ki = 5.4 ± 0.3 μM), with less effect on other enzymes evaluated (IC50 >29 μM; CYP2C9 40.7 ± 4.1 μM, CYP1A2 29.8 ± 3.6 μM, others >50 μM).
  • Curcuminoid extract and piperine inhibited recombinant CYP3A4 much more potently than CYP3A5: curcuminoid extract IC50 20.3 ± 0.7 μM vs >200 μM; piperine IC50 8.0 ± 1.8 μM vs >50 μM.
  • Among pure synthetic curcuminoids, demethoxycurcumin was more active against CYP2C9 (IC50 8.8 ± 1.2 μM) than curcumin or bisdemethoxycurcumin (IC50 >50 μM); all three had similar effects on CYP3A, UGT, and SULT activity. Curcumin had a lower IC50 for acetaminophen glucuronidation in intact LS180 cells (2.2 ± 0.1 μM).

Methods

  • In vitro study using human liver microsomes, human liver cytosol, recombinant CYP3A4 and CYP3A5, and LS180 colon cells. CYP probe activities included triazolam 1′-hydroxylation (CYP3A), flurbiprofen hydroxylation (CYP2C9), S-mephenytoin hydroxylation (CYP2C19), phenacetin de-ethylation (CYP1A2), dextromethorphan demethylation (CYP2D6), chlorzoxazone hydroxylation (CYP2E1), and bupropion hydroxylation (CYP2B6); UGT and SULT activities used acetaminophen glucuronidation and sulfation.
  • IC50 and Ki values were determined by nonlinear regression; inhibition models included competitive, mixed competitive-noncompetitive, and noncompetitive. Time-dependent inhibition was assessed with 20-min preincubation and additional preincubation times for CYP3A.
  • Curcuminoid extract was analyzed by HPLC and contained 66% curcumin, 23% demethoxycurcumin, and 11% bisdemethoxycurcumin. Pure curcuminoids were synthesized and tested individually and as a mixture. Human liver microsomes from 50 individuals were pooled for UGT assays; individual high-activity livers were used for CYP assays; cytosol was pooled from four livers.

Limitations

  • Stated: the study is in vitro, and controlled drug interaction studies in human subjects are warranted. The authors note that non-specific microsomal binding of curcuminoids was not evaluated and could lead to underestimation of inhibition potency; piperine plasma levels have not been reported; and it is not yet clear which UGT and SULT isozymes predominate in intestinal mucosa.
  • Stated: predictions of intestinal interaction are based on expected tissue concentrations from oral dosing, not on measured human intestinal concentrations or clinical outcomes.
  • Evident from the text: no in vivo human drug-interaction data are presented, and the relatively high acetaminophen concentration used (10 mM) may have minimized competitive inhibition by piperine.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1124/dmd.108.020552

Cites

40 of 40 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

0 Valid · 0 Not valid · 16 Not checked · 78 Own results and interpretations

60 more claims

Create a free account to see all 94 claims and to verify the 25 references still open.

See all claims — free account
  • It may state two separate claims as one. 23
  • Probably not a substantial claim. 13

Create a free account to see these claims.

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

4 of 4

Citations

Cites

Show all 42 references

Cited by

Items 101–200 of 214

Metadata

Authors
Volak, L. P., Ghirmai, S., Cashman, J. R., & Court, M. H.
Affiliations
Tufts University (US)
Venue
Drug Metabolism and Disposition
Publisher
Elsevier BV
Published
2008-08
Volume
36
Issue
8
Pages
1594-1605
ISSN
0090-9556 (ISSN-L)
OpenAlex
W2118356995
Cited by
214
References
42
Citations by year
2026: 27 · 2025: 20 · 2024: 7 · 2023: 7 · 2022: 11 · 2021: 20 · 2020: 15 · 2019: 8 · 2018: 11 · 2017: 8 · 2016: 13 · 2015: 10 · 2014: 14 · 2013: 8 · 2012: 14
FWCI
4.37
Type
journal article
Language
en
Open access
Licence
  • www.elsevier.com/tdm/userlicense/1.0/ (tdm)
  • www.elsevier.com/legal/tdmrep-license (tdm)
Locations
  • Drug Metabolism and Disposition (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
Funders
  • Pfizer UK
  • National Institute of General Medical Sciences (R01GM061834, R21GM074369)
  • National Center for Complementary and Integrative Health (F31AT003973)
Topics
  • Life Sciences › Pharmacology, Toxicology and Pharmaceutics › Pharmacology › Pharmacogenetics and Drug Metabolism
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Medicine › Curcumin's Biomedical Applications
  • Health Sciences › Medicine › Oncology › Drug Transport and Resistance Mechanisms
Keywords
curcuminoids, piperine, herb-drug interactions, cytochrome P450 inhibition, CYP3A4, CYP2C9, CYP2C19, UDP-glucuronosyltransferase, sulfotransferase, curcumin, demethoxycurcumin, bisdemethoxycurcumin, enzyme inhibition kinetics
MeSH terms
Acetaminophen, Alkaloids, Chromatography, High Pressure Liquid, Curcumin, Enzyme Inhibitors, Humans, Liver, Piperidines, Recombinant Proteins, Spectrometry, Fluorescence, Spectrophotometry, Ultraviolet, Glucuronosyltransferase, Sulfotransferases, Spectrometry, Mass, Electrospray Ionization, Benzodioxoles, Polyunsaturated Alkamides, Cytochrome P-450 Enzyme Inhibitors

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

A language model drew the claims from the paper on 2026-11-14, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).

A second model labelled each claim on 2026-11-14 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review

Data sources

Bibliographic data: Semantic Scholar, OpenAlex, Crossref.

Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).

Semantic Scholar’s data is described in: Kinney, R., et al. (2023). The Semantic Scholar Open Data Platform. arXiv:2301.10140.