Quercetin: powerful healing, antiviral and anti-aging agent

QUERCETIN

Scientific evidence indicates that quercetin contains intense antioxidant, anti-inflammatory and anti-aging properties.  Although it is the most abundant flavonoid in the human diet, the concentration of quercetin in a food depends greatly on the way it has been cultivated.

Today we will learn what quercetin is, its benefits in the human body and how to obtain it from food or as a supplement.

Quercetin is a plant pigment from the flavonoid group present in polyphenolic compounds of plants and in a wide variety of vegetables and fruits. But let's see how quercetin acts in the human body.

Quercetin has a double antioxidant mechanism:

As a direct antioxidant by scavenging reactive oxygen species (ROS) and nitrogen species (RNS) that are generated during metabolic processes or also from pollution, radiation, and cleaning products that accumulate in the body and cause oxidative damage to DNA, proteins, and lipids.

As an indirect antioxidant by activating antioxidant enzymes while inhibiting oxidative enzymes. Oxidative damage contributes to aging by being part of chronic and degenerative diseases. In this sense, quercetin can reduce the risk of acquiring diseases related to aging, including heart disease .

Benefits of quercetin in the human body

Against inflammation:

Quercetin exerts its anti-inflammatory activity by inhibiting inflammatory enzymes such as cyclooxygenase 2 COX-2 and lipoxygenase by decreasing inflammatory mediators such as prostaglandins and leukotrienes (molecules that participate in chronic inflammation processes, increasing vascular permeability and therefore promoting edema in the affected area).

The anti-inflammatory and antioxidant properties of quercetin are believed to be effective in preventing chronic diseases such as cardiovascular disease, obesity and rheumatoid arthritis.

Antioxidant action against high blood pressure

Hypertension, if left untreated, can lead to heart disease and stroke. Preclinical results suggest that quercetin contributes its antioxidant action to promote cardiovascular health. ( study )

Wound healing :

Wounds need to heal quickly to prevent infection. However, if they heal too quickly, excessive fibrous tissue forms. This process, known as fibrosis, leads to scarring, which causes both functional and cosmetic problems. Quercetin has anti-fibrotic properties and some studies have shown the potential for quercetin to improve wound healing and reduce scar formation. ( study )

Onion extract containing quercetin, as well as other phenolic compounds, is an ingredient present in many commercial wound healing gels. A meta-analysis of 13 studies involving 600 people who used wound healing gels found that methodologies differed markedly with follow-up periods ranging from 10 weeks to 6 months.

There were different results, probably due to the use of different formulas or the amount of quercetin the products contained. More tests with standardized methods are needed to confirm whether quercetin actually has healing-health effects in humans. ( study )

Quercetin against viral infections:

One mechanism by which quercetin exerts beneficial effects lies in its ability to serve as an ionophore. An ionophore is a compound that can transport ions across the semipermeable lipid bilayer surrounding cells.

In viral disease, the activity of zinc is particularly relevant, an essential nutrient that inhibits the action of RNA-dependent RNA polymerase (RdRp), the critical enzyme for the reproduction of RNA viruses, type SARS-CoV-2.

Essentially, what zinc does is block the ability of viruses to replicate. However, zinc is a positively charged ion that cannot enter cells to perform its function without the help of a transporter. Quercetin is a known ionophore.

Quercetin as an anti-aging agent

Senescence is a condition or process of cellular deterioration that occurs with age. Senescent cells accumulate in the body over time and have properties that distinguish them from normal cells. For example, they do not replicate and instead of dying, they secrete dangerous molecules that damage or eliminate neighboring cells. ( Study )

Research indicates that certain substances known as senolytic compounds may help treat age-related diseases. One example is that directly targeting senescent cells could benefit chronic conditions that reduce human health and life span, such as obesity and diabetes, since in these cases senescent cells accumulate in the fat and other tissues of people with these conditions. ( study )

Obesity triggers an early senescence program in fat cells of obese individuals. Removing these cells could alleviate complications of these conditions and increase insulin sensitivity. In addition, decreasing senescent cells should reduce age-related frailty.

Quercetin is one of the first senolytic compounds discovered that is believed to be beneficial against the effects of aging. Although quercetin alone cannot eliminate senescent cell types, it does work in conjunction with another agent and is often used with Dasatinib, an anti-cancer drug known as DQ.

Together with the drug Dasatinib, quercetin could also act to combat osteoporosis, pulmonary fibrosis and even kidney diseases resulting from diabetes, hypertension and obesity.

Where can you find quercetin?

Quercetin found in foods occurs in the form of glycosides, attached to a sugar molecule, while the supplemental form of quercetin usually occurs in the form of an aglycone.  Quercetin aglycone can passively diffuse through the small intestine wall or be transported by sodium/glucose cotransporter-1. Once absorbed, quercetin undergoes extensive biotransformation in the liver and as a consequence, the product delivered to cells is often markedly different from the original. ( study )

It is best to rely on food sources that contain quercetin, among the known foods that contain it, let's see the following table:

Food source	Amount of quercetin in mg/100g in an edible portion
Raw capers	233.84
Yellow chili, spicy, raw	50.73
Red onions, raw	39.21
Asparagus, cooked	15.16
Cranberries, raw	14.84
Green, spicy, raw bell peppers	14.70
Blueberries, raw	7.67
Purple lettuce, raw	7.61
White onion, raw	6.17
Tomato, canned	4.17
Red apple, with peel	3.86
Gala apple, with peel	3.80
Yellow apple, with peel	3.69
Broccoli, raw	3.26
Green tea, in infusion	2.49
Sweet Cherries, Raw	2.29
Black tea, in infusion	2.19
Grapes, black	2.08
White grapes	1.12
Red wine, table wine	1.04
White table wine	0.04

The bioavailability or how much quercetin enters the bloodstream is not really much since its absorption is influenced by several factors such as dosage, planting protocol, harvesting and formulation; but also the metabolic individuality of the person who consumes it since the good or bad absorption of quercetin depends on the state of the intestinal flora.

The benefits of quercetin are highly promising, but the best strategy for now is to consume organic foods high in quercetin and maintain a healthy colon to reap all the benefits it provides.