Elsevier

Metabolism Open

Volume 11, September 2021, 100115
Metabolism Open

A systematic review on the effects of Echinacea supplementation on cytokine levels: Is there a role in COVID-19?

https://doi.org/10.1016/j.metop.2021.100115Get rights and content
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Highlights

  • Modulation of the immune system has been identified as a possible management strategy in severe COVID-19.

  • A systematic review of all studies assessing changes in cytokine levels following Echinacea supplementation was undertaken.

  • Echinacea supplementation may decrease the pro-inflammatory cytokines IL-6, IL-8, and TNF.

  • Echinacea supplementation may increase the anti-inflammatory cytokine IL-10.

  • Clinical trials assessing the effectiveness of Echinacea in the treatment of cytokine storm in COVID-19 may be warranted.

Abstract

COVID-19 is the respiratory illness caused by the novel coronavirus, SARS-CoV-2. Cytokine storm appears to be a factor in COVID-19 mortality. Echinacea species have been used historically for immune modulation. A previous rapid review suggested that Echinacea supplementation may decrease the levels of pro-inflammatory cytokines involved in cytokine storm. The objective of the present systematic review was to identify all research that has assessed changes in levels of cytokines relevant to cytokine storm in response to administration of Echinacea supplementation. The following databases were searched: Medline (Ovid), AMED (Ovid), CINAHL (EBSCO), EMBASE (Ovid). Title and abstract screening, full text screening, and data extraction were completed in duplicate using a piloted extraction template. Risk of bias assessment was completed. Qualitative analysis was used to assess for trends in cytokine level changes. The search identified 279 unique publications. After full text screening, 105 studies met criteria for inclusion including 13 human studies, 24 animal studies, and 71 in vitro or ex vivo studies. The data suggest that Echinacea supplementation may be associated with a decrease in the pro-inflammatory cytokines IL-6, IL-8, and TNF, as well as an increase in the anti-inflammatory cytokine IL-10. The risk of bias in the included studies was generally high. While there is currently no substantive research on the therapeutic effects of Echinacea in the management of either cytokine storm or COVID-19, the present evidence related to the herb's impact on cytokine levels suggests that further research may be warranted in the form of a clinical trial involving patients with COVID-19.

Keywords

Echinacea
Herbal medicine
Cytokine
Cytokine storm
Cytokine release syndrome
COVID-19

Abbreviations

ARDS
acute respiratory distress syndrome
CCL
C–C motif ligand chemokine
COVID-19
coronavirus disease 2019
CSF
Colony-stimulating factor
GM-CSF
granulocyte-macrophage colony-stimulating factor
IFN
interferon
IL
interleukin
MCP
monocyte chemoattractant protein
MIP
macrophage inflammatory protein
SARS
Severe acute respiratory syndrome
SARS-CoV-2
severe acute respiratory syndrome coronavirus 2
TFN
tumor necrosis factor

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