Can Natural Polyphenols Help in Reducing Cytokine Storm in COVID-19 Patients?

Molecules (Basel, Switzerland). 2020;25(24)

Plain language summary

During covid-19 infection the body experiences a hyper-immune reaction resulting in an extreme inflammatory response known as cytokine release syndrome (CRS), which correlates with poor prognosis and severe illness. There are no effective treatments for CRS, although there are ongoing trials. The use of natural plant chemicals known as polyphenols have been shown in previous trials to improve inflammation This review of over 90 studies aimed to summarise the use of polyphenols to fight severe covid-19 infection. The paper began by reviewing current drug therapies, which have been shown in studies to be of benefit to inflammation, with tocilizumab being heavily reviewed. The authors then reviewed several plant polyphenols and reviewed how they can modulate inflammation through inhibiting inflammatory molecules and viral activity. It was concluded that human studies are lacking data and so phytochemicals may be promising for the treatment of covid-19. This study could be used by health care professionals to understand the importance of recommending a whole food, plant rich diet with many different coloured foods for individuals who are suffering from covid-19.


SARS-CoV-2 first emerged in China during late 2019 and rapidly spread all over the world. Alterations in the inflammatory cytokines pathway represent a strong signature during SARS-COV-2 infection and correlate with poor prognosis and severity of the illness. The hyper-activation of the immune system results in an acute severe systemic inflammatory response named cytokine release syndrome (CRS). No effective prophylactic or post-exposure treatments are available, although some anti-inflammatory compounds are currently in clinical trials. Studies of plant extracts and natural compounds show that polyphenols can play a beneficial role in the prevention and the progress of chronic diseases related to inflammation. The aim of this manuscript is to review the published background on the possible effectiveness of polyphenols to fight SARS-COV-2 infection, contributing to the reduction of inflammation. Here, some of the anti-inflammatory therapies are discussed and although great progress has been made though this year, there is no proven cytokine blocking agents for COVID currently used in clinical practice. In this regard, bioactive phytochemicals such as polyphenols may become promising tools to be used as adjuvants in the treatment of SARS-CoV-2 infection. Such nutrients, with anti-inflammatory and antioxidant properties, associated to classical anti-inflammatory drugs, could help in reducing the inflammation in patients with COVID-19.

Lifestyle medicine

Fundamental Clinical Imbalances : Immune and inflammation
Patient Centred Factors : Triggers/Covid-19
Environmental Inputs : Nutrients
Personal Lifestyle Factors : Nutrition
Functional Laboratory Testing : Not applicable

Methodological quality

Jadad score : Not applicable
Allocation concealment : Not applicable
Publication Type : Journal Article ; Review


Nutrition Evidence keywords : Cytokine release syndrome ; CRS ; Cytokine storm