Cited by 182COVID-19 Clinical Research StudiesFlavonoids in Medical ResearchPhytochemicals and Antioxidant Activities

Possible Therapeutic Effects of Adjuvant Quercetin Supplementation Against Early-Stage COVID-19 Infection: A Prospective, Randomized, Controlled, and Open-Label Study

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Di Pierro, Francesco, Derosa, Giuseppe, Maffioli, Pamela, Bertuccioli, Alexander, Togni, Stefano, Riva, Antonella, Allegrini, Pietro, Khan, Amjad +11 more·2021·International Journal of General Medicine

Abstract

Background: Quercetin, a well-known naturally occurring polyphenol, has recently been shown by molecular docking, in vitro and in vivo studies to be a possible anti-COVID-19 candidate. Quercetin has strong antioxidant, anti-inflammatory, immunomodulatory, and antiviral properties, and it is characterized by a very high safety profile, exerted in animals and in humans. Like most other polyphenols, quercetin shows a very low rate of oral absorption and its clinical use is considered by most of modest utility. Quercetin in a delivery-food grade system with sunflower phospholipids (Quercetin Phytosome ® , QP) increases its oral absorption up to 20-fold. Methods: In the present prospective, randomized, controlled, and open-label study, a daily dose of 1000 mg of QP was investigated for 30 days in 152 COVID-19 outpatients to disclose its adjuvant effect in treating the early symptoms and in preventing the severe outcomes of the disease. Results: The results revealed a reduction in frequency and length of hospitalization, in need of non-invasive oxygen therapy, in progression to intensive care units and in number of deaths. The results also confirmed the very high safety profile of quercetin and suggested possible anti-fatigue and pro-appetite properties. Conclusion: QP is a safe agent and in combination with standard care, when used in early stage of viral infection, could aid in improving the early symptoms and help in preventing the severity of COVID-19 disease. It is suggested that a double-blind, placebo-controlled study should be urgently carried out to confirm the results of our study. Keywords: SARS-CoV-2, infectious diseases, coronavirus, pneumonia, botanicals, 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 [144]

  • 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 [144]

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Research works printed but not linked: 1

  1. [12]Khaerunnisa S, Kurniawan H, Awaluddin R, Suhartati S, Soetjipto S. Potential inhibitor of COVID-19 main protease (Mpro) from several medicinal plant compounds by molecular docking study. Preprints. 2020. doi: 10.20944/preprints.202003.0226.v1 · DOI

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Authors
Di Pierro, F., Derosa, G., Maffioli, P., Bertuccioli, A., Togni, S., Riva, A., Allegrini, P., Khan, A., Khan, S., Khan, B. A., Altaf, N., Zahid, M., Ujjan, I. D., Nigar, R., Khushk, M. I., Phulpoto, M., Lail, A., Devrajani, B. R., & Ahmed, S.
Affiliations
  • University of Pavia (IT)
  • University of Urbino (IT)
  • Indena (Italy) (IT)
  • University of Health Sciences Lahore (PK)
  • Dow University of Health Sciences (PK)
  • Liaquat University of Medical & Health Sciences (PK)
  • Shifa Tameer-e-Millat University (PK)
Venue
International Journal of General Medicine
Published
2021-06
Volume
Volume 14
Pages
2359-2366
ISSN
1178-7074 (ISSN-L)
OpenAlex
W3166542025
Cited by
182
References
30
Citations by year
2026: 6 · 2025: 19 · 2024: 30 · 2023: 39 · 2022: 66 · 2021: 22
FWCI
12.39
Type
journal article
Language
en
Open access
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 › Biochemistry › Phytochemicals and Antioxidant Activities
Keywords
quercetin, SARS-CoV-2, COVID-19 pandemic, adjuvant therapy, early-stage infection, polyphenols, oral bioavailability, antioxidant activity, anti-inflammatory activity, immunomodulation, antiviral activity, hospitalization, intensive care unit admission, mortality, safety profile, anti-fatigue

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