Effectiveness of supplementation with quercetin-type flavonols for treatment of viral lower respiratory tract infections: Systematic review and meta-analysis of preclinical studies

source extracted confidence: high 2026-04-09
#animals #dietary-supplements #flavonols #humans #quercetin

Effectiveness of supplementation with quercetin-type flavonols for treatment of viral lower respiratory tract infections: Systematic review and meta-analysis of preclinical studies

Brito et al., 2021 | Phytother Res | Meta Analysis

Citation

Brito Júlio César Moreira, Lima William Gustavo, ... da Cruz Nizer Waleska Stephanie. Effectiveness of supplementation with quercetin-type flavonols for treatment of viral lower respiratory tract infections: Systematic review and meta-analysis of preclinical studies. Phytother Res. 2021-Sep;35(9):4930-4942. doi:10.1002/ptr.7122

Abstract

Viral infections of the lower respiratory tract are considered a public health problem. They affect millions of people worldwide, causing thousands of deaths, and are treated with expensive medicines, such as antivirals or palliative measures. In this study, we conducted a systematic review to describe the use of quercetin-type flavonols against lower respiratory tract viruses and discussed the preclinical impact of this approach on different signs and clinical mechanisms of infection. The systematic review was performed in PubMed/MEDLINE, Scopus, Scielo, and Biblioteca Virtual de Saúde (BVS). After the database search, 11 relevant studies were identified as eligible. The analysis of these studies showed evidence of antiviral activity of quercetin-type flavonols with significantly reduced mortality rate (M-H = 0.19, 95% CI: 0.05 to 0.65, p-value = 0.008) of infected animals and a reduction in the average viral load (IV = -1.93, 95% CI: -3.54 to -0.31, p-value = 0.02). Additionally, quercetin and its derivatives reduced the amount of proinflammatory cytokines, chemokines, reactive oxygen species, mucus production, and airway resistance in animals infected with a respiratory virus. Overall, supplementation with quercetin-type flavonols is a promising strategy for treating viral-induced lower respiratory tract infections.

Key Findings

Overall, supplementation with quercetin-type flavonols is a promising strategy for treating viral-induced lower respiratory tract infections.

Outcomes Measured

  • inflammatory markers

Population

Field Value
Population See abstract
Sample Size See abstract
Age Range See abstract
Condition See abstract

MeSH Terms

  • Animals
  • Dietary Supplements
  • Flavonols
  • Humans
  • Quercetin
  • Respiratory Tract Infections
  • Virus Diseases

Evidence Classification

  • Level: Meta Analysis
  • Publication Types: Journal Article, Meta-Analysis, Systematic Review
  • Vertical: quercetin

Provenance

Source extracted via PubMed E-utilities API on 2026-04-09