Potential Clinical Benefits of Quercetin in the Early Stage of COVID-19: Results of a Second, Pilot, Randomized, Controlled and Open-Label Clinical Trial
Open accessAbstract
Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the ongoing global pandemic known as COVID-19. Based on the potential antiviral role of quercetin, and on its described anti-blood clotting, anti-inflammatory and antioxidant properties, we hypothesize that subjects with mild COVID-19 treated with Quercetin Phytosome ® (QP), a novel bioavailable form of quercetin, may have a shorter time to virus clearance, a milder symptomatology, and higher probabilities of a benign earlier resolution of the disease. Methods: In our 2-week, randomized, open-label, and controlled clinical study, we have enrolled 42 COVID-19 outpatients. Twenty-one have been treated with the standard of care (SC), and 21 with QP as add-on supplementation to the SC. Our main aims were to check virus clearance and symptoms. Results: The interim results reveal that after 1 week of treatment, 16 patients of the QP group were tested negative for SARS-CoV-2 and 12 patients had all their symptoms diminished; in the SC group, 2 patients were tested SARS-CoV-2 negative and 4 patients had their symptoms partially improved. By 2 weeks, the remaining 5 patients of the QP group tested negative for SARS-CoV-2, whereas in the SC group out of 19 remaining patients, 17 tested negatives by week 2, one tested negative by week 3 and one patient, still positive, expired by day 20. Concerning blood parameters, the add on therapy with QP, reduced LDH (− 35.5%), Ferritin (− 40%), CRP (− 54.8%) and D-dimer (− 11.9%). Conclusion: QP statistically shortens the timing of molecular test conversion from positive to negative, reducing at the same time symptoms severity and negative predictors of COVID-19. Keywords: SARS-CoV-2, RT-PCR, LDH, ferritin, CRP, D-dimer, coronavirus, phytosome ®
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Two randomized clinical trials (NCT04578158 and NCT04861298) using a special quercetin formulation with enhanced oral bioavailability as an early intervention in patients with mild COVID-19 symptoms met their clinical end points.
“Further corroborating and extending these preclinical findings to the human condition, two randomized clinical trials (NCT04578158 and NCT04861298) that, in addition to standard care, used a special formulation of quercetin with enhanced oral bioavailability as an early intervention in patients with mild COVID-19 symptoms, met their clinical end points143–145.”
From COVID-19 and cellular senescence (2023) · cites this paper as [145]
In the two COVID-19 trials, quercetin was generally well tolerated with no apparent toxicity and no particular side effects reported by patients.
“Specifically, in the two COVID-19 trials referred to above, quercetin was generally well tolerated with no apparent toxicity and no particular side effects were reported by the patients143–145.”
From COVID-19 and cellular senescence (2023) · cites this paper as [145]
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- Authors
- Di Pierro, F., Iqtadar, S., Khan, A., Ullah Mumtaz, S., Masud Chaudhry, M., Bertuccioli, A., Derosa, G., Maffioli, P., Togni, S., Riva, A., Allegrini, P., & Khan, S.
- Affiliations
- King Edward Medical University (PK)
- University of Health Sciences Lahore (PK)
- University of Urbino (IT)
- University of Pavia (IT)
- Indena (Italy) (IT)
- Dow University of Health Sciences (PK)
- ORCID
- Venue
- International Journal of General Medicine
- Publisher
- Informa UK Limited
- Published
- 2021-06
- Volume
- Volume 14
- Pages
- 2807-2816
- ISSN
- 1178-7074 (ISSN-L)
- PMC
- PMC8238537
- OpenAlex
- W3173557551
- Cited by
- 180
- References
- 34
- Citations by year
- 2026: 9 · 2025: 21 · 2024: 27 · 2023: 41 · 2022: 60 · 2021: 21
- FWCI
- 11.80
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Licence
- Locations
- International Journal of General Medicine (publishedVersion, cc-by-nc)
- PubMed Central (publishedVersion, cc-by-nc)
- PubMed (publishedVersion)
- Dove Medical Press (Taylor and Francis Group) (submittedVersion, cc-by-nc)
- Topics
- Health Sciences › Medicine › Infectious Diseases › COVID-19 Clinical Research Studies
- Health Sciences › Medicine › Pharmacology › Flavonoids in Medical Research
- Health Sciences › Medicine › Infectious Diseases › SARS-CoV-2 and COVID-19 Research
- Keywords
- quercetin, COVID-19 pandemic, SARS-CoV-2, mild COVID-19, viral clearance, symptom severity, LDH, ferritin, C-reactive protein, D-dimer, biomarkers
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