QUERCETIN: WHAT IS IT?

Quercetin is a flavonoid found naturally in a wide variety of fruits and vegetables.

Chemically, most flavonoids consist of a central skeleton composed of 15 carbon atoms and, specifically, 3 rings, 2 of which are benzyl and 1 heterocyclic.

Quercetina - Wikipedia

 

QUERCETIN IN FOOD

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Quercetin is a ubiquitous flavonoid. The foods containing the most quercetin are:

Food  Quantity of Quercetin mg/100 g 
Capers 234
Dill 79,0
Fennel leaves 46,8
Oregano 42,0
Chilli 32,6
Spinach 27,2
Cabbage 22,6
Cherry 17,4
Lettuce 14,7
Asparagus 14,0-23,6
Romaine lettuce 12,0
Onions 11-45,0
Chives 10,4
Red lettuce 10,3-30,6
Green pepper 9,9
Wild leeks 8,36
Apples 4,01
Fuji Apples 2,3
Tomatoes 1,6-3,3
Leeks 0,9
Broccoli 0,5-13,7

QUERCETIN IN MEDICINAL PLANTS

Good levels of quercetin can also be found in some medicinal plants such as:

  • Hypericum
  • Horse chestnut
  • Ginkgo Biloba
  • Sophora Japonica (Also known as Acacia of Japan, from which a particularly pure extract is obtained from the inflorescence).

estratto puro 98% di sophora japonica della parte del germoglio di fiore della polvere della rutina di 95%

THE RECOMMENDED DAILY DOSE OF QUERCETIN

The recommended intake is around 500 mg per day; however, with a Western-style diet, a daily intake of around 30 mg is possible.

THE ROLE OF QUERCETIN

Quercetin has several important functions:

  •  Antioxidant: reduces the formation of free radicals.

QUERCETINA ANTIOSSIDANTE POTENTE | Salvatori Giovanni

  • Anti-inflammatoryanti-allergic: inhibits histamine release, as it reduces mast cell inflammation.

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  • Immunomodulatory: decreases pro-inflammatory cytokines.
  • Antiviral: transports zinc into cells, where it acts by preventing virus replication.

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  • Immunomodulatory-antioxidant: possesses anti-cancer potential, as it reduces the risk of cell alterations.

 

In addition, this flavonoid has a synergistic action with vitamin C, which increases its bioavailability, resulting in an anti-inflammatory-antioxidant action.

QUERCETIN SUPPLEMENTS

Quercetina, dove si trova e cosa c'è da sapere sulla molecola anti-Covid | Vanity Fair Italia

Although there are foods rich in quercetin, as is illustrated in the table above, the use of food supplements containing this flavonoid is recommended, due to both the low proportion provided by the foods themselves and its poor bioavailability.
Indeed, precisely because of quercetin’s poor bioavailability and thus its poor absorption in the intestines, it is very common to find food supplements containing, in addition to quercetin, vitamin C, which increases its bioavailability.
In healthy adults, at the recommended daily dose, preferably taken with meals, quercetin is safe and well tolerated.