- Fisetin has been shown to reduce the burden of COVID-19 in the lab and an animal model with significant results; researchers are now testing it in skilled nursing facility residents
- Fisetin is a flavonoid with known senolytic properties, which help reduce the number of senescent cells in the body. These cells have lost the ability to proliferate and are resistant to apoptosis
- The foods highest in fisetin are strawberries; yet you need to eat 37 strawberries each day to get the benefits. The compound also extended the health span of animals used in the study
- Fisetin has been shown to have anti-inflammatory and antitumorigenic properties, to inhibit bone-damaging glycation, to maintain glutathione levels, and to protect brain function
Fisetin is a flavonoid molecule that's found in fruits and vegetables. An animal study published in July 20211 demonstrated that it may help reduce the mortality rate in older adults with COVID-19. A human study2 is underway to analyze the effect it may have on elderly patients with COVID-19.
There are nearly 6,000 flavonoids3 found in fruits, vegetables, herbs and medicinal plants. Flavonoids are also antioxidants and have a number of subclasses, including flavanols, flavones and flavanones.4 During 2020, there was a growing focus on the value of antioxidants in the fight against infectious diseases.
As the science grows, researchers are becoming interested in individual flavonoids for the positive effect they can have on human health. Past research has suggested that fisetin may help extend a healthy life span by acting as a senolytic.5
These are a class of molecules that can selectively induce the death of senescent cells. Currently, there are 16 research studies registered with ClinicalTrials.gov studying fisetin.6 Of these, 13 are in the initial stages, either enrolling, recruiting or not yet recruiting participants.
Flavonoid compounds are well-known for their antioxidant, anti-inflammatory, anticarcinogenic and antimutagenic properties.7 They have become indispensable in a variety of applications including the pharmaceutical, nutraceuticals and cosmetic industries. Although scientists are continuing to study the mechanism of action flavonoids' use in the body, the plant derivatives have been widely used for centuries.
Fisetin Reduced the Burden of COVID in the Lab
Many of the biological effects that flavonoids have on the human body are related to modulating cell signaling cascades.8 This is how they protect against inflammation, thrombogenesis, diabetes and cancer development. Past studies have shown promising results when supplementation is used to improve glycemic control, enhance cognitive function, or in the prevention of cancer.
Fisetin is being studied to help reduce the severity of COVID-19 in elderly patients.9 In an animal study10 published in July 2021, researchers studied the response to stress signals that were associated with senescent cells known to increase in number with age.
They demonstrated that senescent cells increase the risk of severe COVID-19. Since the senescent cells secrete proinflammatory factors, they hypothesized these may heighten the proinflammatory response and raise the risk of cytokine storms and multi-organ failure.
To test the hypothesis, the researchers used human cells in a lab study and old mice that were challenged with lipopolysaccharide. The results demonstrated that senescent cells increased the susceptibility to SARS-CoV-2 and induced hyperinflation. When the researchers used senolytic compounds to reduce the burden of senescent cells, the mortality declined.
The senolytic compound they used to induce the death of senescent cells was fisetin. They believe the data suggests "senolytics might protect others vulnerable to adverse COVID-19 outcomes in whom increased SnCs [senescent cells] occur (such as in obesity or numerous chronic diseases)."11
In one of the studies, the researchers found older mice exposed to a normal microbial environment, including SARS-CoV-2-related mouse beta coronavirus, experienced 100% lethality within 2 weeks. By comparison, those exposed to the same microbes but treated with fisetin had a significant improvement in survival — 64% of the male mice and 22% of the females survived long-term with an extension in lifespan for both sexes.12