Tier 2 — strong

Pharmacokinetics and bioavailability of quercetin glycosides in humans

E U Graefe, J Wittig, S Mueller, A K Riethling, B Uehleke, B Drewelow, H Pforte, G Jacobasch, H Derendorf, M Veit
Journal of clinical pharmacology 2001 41(5):492

Bibliography

PubMed
PMID 11361045
DOI
10.1177/00912700122010366
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

DesignFour-way crossover human absorption study
ModelHuman intervention research
Sample12 healthy volunteers
InterventionOnion supplement or quercetin-4-glucoside equivalent to 100 mg quercetin; rutin or buckwheat tea equivalent to 200 mg
DurationSingle-dose comparisons
EndpointsExposure and pharmacokinetics

What the study showed, in plain terms

Published in 2001, this source examined forms, absorption and food sources. Design: Four-way crossover human absorption study. Sample/model: 12 healthy volunteers. The exposure or intervention was Onion supplement or quercetin-4-glucoside equivalent to 100 mg quercetin; rutin or buckwheat tea equivalent to 200 mg. Follow-up or treatment period: Single-dose comparisons.

Glucoside-containing treatments produced earlier, higher plasma conjugate concentrations than rutin-containing treatments; free quercetin was not detected.

Different doses and chemical forms were compared. Plasma exposure to metabolites is not evidence of superior clinical efficacy.

Continue with Quercetin Data Center

For topic-level interpretation, read Quercetin Forms: Dihydrate, Phytosome, Liposomal and Glycosides. This is a related guide; the citation panel separately identifies articles that directly cite this paper.

Key findings

  • Glucoside-containing treatments produced earlier, higher plasma conjugate concentrations than rutin-containing treatments; free quercetin was not detected.
  • The recorded outcome domains were Exposure and pharmacokinetics.
  • The result applies to the tested exposure: Onion supplement or quercetin-4-glucoside equivalent to 100 mg quercetin; rutin or buckwheat tea equivalent to 200 mg; Single-dose comparisons.

What this study can and cannot tell us

  • Different doses and chemical forms were compared. Plasma exposure to metabolites is not evidence of superior clinical efficacy.
  • 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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Citation network

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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