UK study reveals quercetin’s anti-inflammatory effects in blood vessel cells

05 Feb 2021 --- A UK study from the Quadram Institute has identified how quercetin may reduce heart disease risk by reducing vascular inflammation. 

Quercetin is a common polyphenol compound found in onions, apples, tea, broccoli and other leafy vegetables, which may be able to alter metabolic processes in endothelial cells – the cells lining blood vessels.

“This research provides evidence of a mechanism that may explain why people who consume the highest quantities of quercetin in their diets have a lower risk of developing cardiovascular diseases,” says Dr. Paul Kroon, who led the study. 

Altering purine 
The study published in Molecular Nutrition & Food suggests that quercetin’s anti-inflammatory effects in blood vessel lining centers on its role in purine metabolism. 

Purines are key compounds across all forms of life, involved in signaling and metabolic processes, and are part of the way cells use and store energy.

Further experiments showed that quercetin and its modified forms inhibit certain enzymes involved in purine processing.

Quercetin ameliorated inflammation caused by high glucose concentrations and pro-inflammatory treatments in human umbilical vein endothelial cells.The problem of inflammation 
Inflammation is a natural process used by the body to protect itself against immediate harm, but it can have chronic effects if it is prolonged over time.

Ongoing endothelial inflammation may develop into atherosclerosis, a major contributor to heart disease. 

High blood glucose levels due to diabetes or eating a carbohydrate-rich meal can exacerbate these cells’ inflammation. 

Creating a model
The findings come from a study using cultured endothelial cells collected from blood vessels in donated umbilical tissue. 

Human umbilical vein endothelial cells (HUVECs) can be grown in the lab to provide a useful model of the way endothelial cells in blood vessels behave. 

This model system has been used extensively in the study of diabetes and cardiovascular disease.

Previous studies with HUVECs showed how endothelial cells react to inflammation triggers, as well as elevated glucose concentrations. 

The aim of the new study was to understand the effects of quercetin on HUVECs, and also to see if it could mitigate the pro-inflammatory triggers.

Identifying the mechanism
The research team used metabolomics to look at a wide range of HUVEC metabolites under pro-inflammatory and high glucose conditions. 

They then compared these results with the metabolite profile in the presence of quercetin.

The researchers show that high glucose concentrations and pro-inflammatory treatments affect how the cells generate and use energy.

However, the changes were ameliorated by quercetin and its modified forms, leading to more anti-inflammatory and fewer pro-inflammatory metabolites.

An open approach
The strength of this metabolomics approach is that it is untargeted, rather than concentrating on one gene, metabolite or process. 

This gives a wider picture of the systemic response. It can also take into account how quercetin itself, once taken up, is modified by the cells into different forms.

The research was funded by the Biotechnology and Biological Sciences Research Council (BBSRC), part of UK Research and Innovation (UKRI).

Quercetin across industry 
This week quercetin was spotlighted as a key ingredient in Anagenix’s new Viro-Defence Lung Formulation. It is designed to support those with “increased risks of inappropriate inflammation and cytokine storms associated with viral infections.”

Quercetin also features in SternLife’s Immune Protect concept, along with green tea, licorice root, the Ayurvedic medicinal plant Andrographis paniculata and other vitamins and minerals. It is positioned for a positive effect on respiratory function and to exert anti-inflammatory action.

The compound has also been known to increase the effects of zinc, an important micronutrient associated with the immune system.

Edited by Missy Green