Tier 2 — strong

Simultaneous action of the flavonoid quercetin on cytochrome P450 (CYP) 1A2, CYP2A6, N-acetyltransferase and xanthine oxidase activity in healthy volunteers

Yao Chen, Peng Xiao, Dong-Sheng Ou-Yang, Lan Fan, Dong Guo, Yi-Nan Wang, Yang Han, Jiang-Hua Tu, Gan Zhou, Yuan-Fei Huang, Hong-Hao Zhou
Clinical and experimental pharmacology & physiology 2009 36(8):828-33

Bibliography

PubMed
PMID 19215233
DOI
10.1111/j.1440-1681.2009.05158.x
Funding
Funding was not specified in the indexed record or the disclosure metadata available for this entry.
Competing interests
A competing-interest declaration was not available in the indexed record or the disclosure metadata used for this entry.

Study snapshot

DesignWithin-subject human enzyme-probe interaction study
ModelHuman intervention research
Sample12 healthy volunteers
InterventionQuercetin 500 mg/day for 13 days with caffeine 100 mg as probe
DurationTwo phases
EndpointsExposure and pharmacokinetics

What the study showed, in plain terms

Published in 2009, this source examined safety, interactions and special populations. Design: Within-subject human enzyme-probe interaction study. Sample/model: 12 healthy volunteers. The exposure or intervention was Quercetin 500 mg/day for 13 days with caffeine 100 mg as probe. Follow-up or treatment period: Two phases.

Caffeine-metabolite ratios suggested lower CYP1A2 activity but higher activity of several other measured pathways.

Small unblinded sequence and indirect enzyme measures. Laboratory xanthine-oxidase inhibition should not be assumed to occur identically in humans.

Continue with Quercetin Data Center

For topic-level interpretation, read Quercetin Interactions: Medicines, Evidence and Precautions. This is a related guide; the citation panel separately identifies articles that directly cite this paper.

Key findings

  • Caffeine-metabolite ratios suggested lower CYP1A2 activity but higher activity of several other measured pathways.
  • The recorded outcome domains were Exposure and pharmacokinetics.
  • The result applies to the tested exposure: Quercetin 500 mg/day for 13 days with caffeine 100 mg as probe; Two phases.

What this study can and cannot tell us

  • Small unblinded sequence and indirect enzyme measures. Laboratory xanthine-oxidase inhibition should not be assumed to occur identically in humans.
  • A change in blood exposure or a metabolic marker is not a demonstrated improvement in symptoms, disease events or lifespan. The tested formulation and co-administered medicines matter.
  • Source basis: Source check: PubMed abstract and indexed metadata; full methods were not independently confirmed for this entry. Missing method details, funding information or participant denominators are not inferred.

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Editorial review

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Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction Dr. Amr Yasser, PhDCardiometabolic, Musculoskeletal, Gut & Bioavailability Dr. Abdulla Mostafa, PhDCellular Senescence, Neurological, Mitochondrial & Brain-Ageing Biology