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Quercetin improves lacrimal gland function through its anti-oxidant actions: Evidence from animal studies, and a pilot study in healthy human volunteers

Takaaki Inaba, Mayumi Ohnishi-Kameyama, Ying Liu, Yasuhisa Tanaka, Masuko Kobori, Shusaku Tamaki, Tomotaka Ito, Kazunari Higa, Jun Shimazaki, Kazuo Tsubota
Frontiers in nutrition 2022 9:974530

Bibliography

PubMed
PMID 36313100
PubMed Central
PMC9599396
DOI
10.3389/fnut.2022.974530
Funding
Funding was not specified in the indexed record or the disclosure metadata available for this entry.
Competing interests
Reported disclosure: Outside the submitted work, Author KT reports his position as CEO of Tsubota Laboratory, Inc., Tokyo, Japan, a company working on treatment, prevention and medical devices for dry eye. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Study snapshot

DesignMouse and cell experiments with a human dietary pilot
ModelMixed human intervention and laboratory research
SampleHealthy human volunteers and diabetic mice; human sample size not stated in the indexed abstract
InterventionQuercetin-rich onion preparations in humans; a separate 0.5% quercetin diet in mice
Duration12 weeks in mice; human schedule not stated in the abstract
EndpointsExposure and pharmacokinetics

What the study showed, in plain terms

Published in 2022, this source examined skin and topical formulations. Design: Mouse and cell experiments with a human dietary pilot. Sample/model: Healthy human volunteers and diabetic mice; human sample size not stated in the indexed abstract. The exposure or intervention was Quercetin-rich onion preparations in humans; a separate 0.5% quercetin diet in mice. Follow-up or treatment period: 12 weeks in mice; human schedule not stated in the abstract.

Human quercetin metabolites appeared in tears, and selected tear-stability measures improved; mouse experiments showed increased tear production.

Species, exposures, and endpoints differ. A small healthy-volunteer pilot does not establish treatment efficacy for clinical dry-eye disease.

Continue with Quercetin Data Center

For topic-level interpretation, read Quercetin Benefits: What Human Studies Actually Show. This is a related guide; the citation panel separately identifies articles that directly cite this paper.

Key findings

  • Human quercetin metabolites appeared in tears, and selected tear-stability measures improved; mouse experiments showed increased tear production.
  • The recorded outcome domains were Exposure and pharmacokinetics.
  • The result applies to the tested exposure: Quercetin-rich onion preparations in humans; a separate 0.5% quercetin diet in mice; 12 weeks in mice; human schedule not stated in the abstract.

What this study can and cannot tell us

  • Species, exposures, and endpoints differ. A small healthy-volunteer pilot does not establish treatment efficacy for clinical dry-eye disease.
  • An individual controlled trial must be interpreted alongside its comparator, sample size, endpoint selection and independent replication. It does not validate a different commercial formulation or a general longevity claim.
  • 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.

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