Trial reportBMJ open respiratory research2020
Randomised clinical trial to determine the safety of quercetin supplementation in patients with chronic obstructive pulmonary disease.
Trial report in BMJ open respiratory research, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to 3 registered trials, which are not on this map. Cited by 78 papers, 2 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Phase I Study to Determine the Safety of Quercetin in COPD Patients
Effects of Quercetin on the Oxidative Stress and Inflammatory Markers in COPD Phase II
The Effects of Quercefit® and Ubiqsome™ in Mitigating Inflammation and Promoting Metabolic Health - A Randomized, Double-Blind, Placebo-Controlled Study
Who cites it
78 citing papers in PubMed, 2 syntheses or guidelines pooled it, 119 citations in OpenAlex.
- Efficacy and safety of dietary polyphenol supplements for COPD: a systematic review and meta-analysis.Frontiers in immunology · 2025Pooled it
- Analysis of the Clinical Efficacy and Molecular Mechanism of Xuefu Zhuyu Decoction in the Treatment of COPD Based on Meta-Analysis and Network Pharmacology.Computational and mathematical methods in medicine · 2022Pooled it
- The Adjunctive Effect of Quercetin on Postoperative Pain Management Following Cesarean Section: A Randomized Controlled Study.Drug design, development and therapy · 2025Trial
- Association between polyphenols and inhalation-induced oxidative stress in chronic lung diseases: A systematic review.Biomedical reports · 2026Article
- Polyphenols as Systems Modulators of the Gut-Brain-Liver Axis: A Narrative Review of Neuro-Metabolic and Immunomodulatory Networks.Molecular nutrition & food research · 2026Review
- SIRT1/AMPK/PGC1α pathway in ischemic stroke: Elucidating neuroprotective strategies (Review).Molecular medicine reports · 2026Review
- Quercetin in COPD: A Multi-Target Approach to Modulate Inflammation, Oxidative Stress, and Epithelial Dysfunction.International journal of molecular sciences · 2026Review
- Flavonoids as Nutraceuticals to Treat Inflammatory Diseases: Focusing on Quercetin, Kaempferol, Luteolin, Apigenin, Epicatechin and Their Effects on Hepatic, Nervous, and Pulmonary Systems.Foods (Basel, Switzerland) · 2026Review
- Food-grade TiOJournal of nanobiotechnology · 2026Article
- A Review of the Potential Therapeutic Benefits of Quercetin for Uterine-Related Conditions.Biomedicines · 2026Review
- Sub-acute intraperitoneal quercetin administration causes dose-dependent organ histopathology and oxidative stress in healthy rats: dissociation between serum biomarkers and tissue-level structural injury.Scientific reports · 2026Article
- Regenerative therapeutics for chronic obstructive pulmonary disease.Pharmacological reviews · 2026Review
- Article
- Beyond Conventional Treatment: Herbal Medicine and Nutraceuticals as Complementary Therapies for COPD and Asthma.The open respiratory medicine journal · 2026Review
- Review
- Efferocytosis in tissue engineering: A comprehensive review of emerging therapeutic strategies for enhanced tissue repair and regeneration.Bioactive materials · 2025Review
- Engineered Anti-Senescence Trachea With Post-Transplanted Regenerative Homeostasis.Advanced science (Weinheim, Baden-Wurttemberg, Germany) · 2025Article
- Research advances in polyphenols from Chinese herbal medicine for the prevention and treatment of chronic obstructive pulmonary disease: a review.Naunyn-Schmiedeberg's archives of pharmacology · 2025Review
- Review
- Mitochondria and Alcohol-Associated Liver Disease: Pathogenic Role and Target for Therapy.Seminars in liver disease · 2025Review
18 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors at 3 institutions in 1 country.
Funding
Abstract
introductionQuercetin is a plant flavonoid and has potent antioxidant and anti-inflammatory properties. In a preclinical model of chronic obstructive pulmonary disease (COPD), quercetin reduced markers of both oxidative stress and lung inflammation and also reduced rhinovirus-induced progression of lung disease. Although quercetin appears to be an attractive natural alternative to manage COPD, the safety of quercetin supplementation in this population is unknown.
methodsWe recruited COPD patients with mild-to-severe lung disease with FVE1 ranging between >35% and <80% and supplemented with either placebo or quercetin at 500, 1000 or 2000 mg/day in a dose-escalation manner. The duration of quercetin supplementation was 1 week.
resultsPatients had no study drug-related severe adverse events based on blood tests, which included both complete blood counts and evaluation of comprehensive metabolic panel. One of the patients reported mild adverse events included gastro-oesophageal reflux disease, which was observed in both placebo and quercetin groups.
conclusionsQuercetin was safely tolerated up to 2000 mg/day as assessed by lung function, blood profile and COPD assessment test questionnaire. TRIAL REGISTRATION NUMBER: NCT01708278.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.