Tier 2 — strong

Effect of enzymatically modified isoquercitrin, a flavonoid, on symptoms of Japanese cedar pollinosis: a randomized double-blind placebo-controlled trial

Mari Kawai, Toru Hirano, Junsuke Arimitsu, Shinji Higa, Yusuke Kuwahara, Keisuke Hagihara, Yoshihito Shima, Masashi Narazaki, Atsushi Ogata, Mihoko Koyanagi, Tomoko Kai, Ryosuke Shimizu, Masamitsu Moriwaki, Yukio Suzuki, Satoshi Ogino, Ichiro Kawase, Toshio Tanaka
International archives of allergy and immunology 2009 149(4):359

Bibliography

PubMed
PMID 19295240
DOI
10.1159/000205582
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

DesignRandomized double-blind placebo-controlled allergy trial
ModelHuman intervention research
Sample20 adults with Japanese cedar pollinosis
InterventionEnzymatically modified isoquercitrin capsules or placebo; dose wording in the abstract requires full-method confirmation
Duration8 weeks during pollen season
EndpointsInflammatory measures; Symptoms and quality of life

What the study showed, in plain terms

Published in 2009, this source examined allergies, histamine and mast cells. Design: Randomized double-blind placebo-controlled allergy trial. Sample/model: 20 adults with Japanese cedar pollinosis. The exposure or intervention was Enzymatically modified isoquercitrin capsules or placebo; dose wording in the abstract requires full-method confirmation. Follow-up or treatment period: 8 weeks during pollen season.

Selected ocular symptoms improved; most nasal and cytokine measures did not show significant differences.

Small trial of a modified glycoside with multiple outcomes. Findings do not establish efficacy of ordinary quercetin for all allergy symptoms.

Continue with Quercetin Data Center

For topic-level interpretation, read Quercetin for Allergies: Hay Fever Evidence and Limits. This is a related guide; the citation panel separately identifies articles that directly cite this paper.

Key findings

  • Selected ocular symptoms improved; most nasal and cytokine measures did not show significant differences.
  • The recorded outcome domains were Inflammatory measures; Symptoms and quality of life.
  • The result applies to the tested exposure: Enzymatically modified isoquercitrin capsules or placebo; dose wording in the abstract requires full-method confirmation; 8 weeks during pollen season.

What this study can and cannot tell us

  • Small trial of a modified glycoside with multiple outcomes. Findings do not establish efficacy of ordinary quercetin for all allergy symptoms.
  • 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.

Related papers in the corpus

Tier 2
Preventative effect of a flavonoid, enzymatically modified isoquercitrin on ocular symptoms of Japanese cedar pollinosis
Toru Hirano et al. · Allergology international : official journal of the Japanese Society of Allergology · 2009

Citation network

Articles citing this research paper

1 article

Biohack Blueprint analyses that reference this study in their evidence base.

Editorial review

Reviewed by the Biohack Blueprint research team

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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