origin

Quercetin is one of the secondary plant substances (phytamines). Secondary plant substances exist in a wide variety of chemical structures, each with specific properties. The best-known groups of secondary plant substances include polyphenols, isoflavones and carotenoids. Quercetin belongs to the group of polyphenols and to their subgroup, the (bio)flavonoids. There are over 5,000 different types of bioflavonoids that occur naturally in plants. In plants, they are responsible for the color of flowers and leaves as well as for protection against UV radiation, predators, viruses, fungi and bacteria. Quercetin is the most common flavonoid and can be used to build other flavonoids.

Quercetin is absorbed into the blood via the intestine (especially the small intestine). According to current studies, slightly less than half of the amount consumed is absorbed by the body and it takes up to nine hours after consumption for the quercetin to be available to the body. The body does not store quercetin permanently, but excretes it again after around 35 hours. Therefore, quercetin should be administered regularly as part of a therapy.

Happen

A high quercetin content can be found, for example, in capers (about 1600 mg quercetin per kg), onions (about 284-486 mg quercetin per kg), chives (245 mg), cranberries (156 mg), black currants (69 mg) and kale (60 mg).

Quercetin is mainly found in the outer shells or layers of plants (e.g. in tree bark) and fruits (e.g. in grapes, apples, onions) to protect them from free radicals. This of course also means that almost no quercetin is absorbed if the outer shells are removed before consumption. For example, quince shells can contain up to 180 mg of quercetin per kg. In the fruiting body itself, on the other hand, there are hardly any relevant amounts of quercetin to be found. However, only minimal amounts can be found inside. In onions, too, around 20% of the quercetin is found directly under the shell and is therefore usually removed when peeling.

The cultivation method is relevant for the quercetin contentFor example, tomatoes from organic farming contain ~ 80% more quercetin than those from conventional farming. In addition, heat during cooking can cause further quercetin losses (according to studies, up to 25%).

Among tree barks, oak bark stands out in terms of its quercetin content, which is where the name “quercetin” comes from - because “quercus” is the Latin name for “oak”; more precisely, for the dyer’s oak (Quercus velutina). However, a very high quercetin content has also been found in the bark of other tree species over time. QIDOSHA quercetin is obtained from the Japanese pagoda tree (Sophora japonica), as its flower extract contains a particularly high amount of natural quercetin.

Benefits and Effects

Since there is hardly any scientific studies on quercetin in humans So-called "health claims", ie promises of health benefits associated with taking the drug, are not permitted. The study situation therefore relates primarily to laboratory and animal experiments. However, since there are numerous promising starting points here, clinical trials on humans are expected in the near future.

It is undisputed that quercetin is a particularly powerful antioxidant which seems to be comparable to OPC or epigallocatechin gallate (EGCG) from green tea leaves.The reason for this lies in the chemical structure of quercetin - it is a polyphenol that has an additional hydroxyl group instead of a sugar molecule. And the more OH groups a polyphenol has, the greater its antioxidant effect.

Another special features of flavonoids like quercetin lies in the ability to regenerate already oxidized substances (e.g. vitamins C and E), ie to restore their restore antioxidant power.

In one meta-study from 2019 to Effects of Quercetin on Diabetes Based on animal studies, researchers were able to find that there was a significant difference in the mean serum glucose levels when 10, 25 and 50 mg of quercetin per kg of body weight were administered. https://pubmed.ncbi.nlm.nih.gov/30735748/

One Japanese study suggests that quercetin anti-allergic effect by inhibiting the so-called histamine H1 receptor (H1R). The severity of allergy symptoms increases in proportion to the activity of this receptor. https://pubmed.ncbi.nlm.nih.gov/23333628/

One study by the University of Naples postulates a anti-inflammatory effect of quercetin, in that it is in principle able to reduce concentrations of the tissue hormone prostaglandin E2 and the fatty acid derivative leukotriene B4. Both substances are relevant for the initiation of inflammatory processes and play a key role in the release of inflammatory mediators such as histamine. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.2042-7158.1988.tb05250.x

One study from 2007 blood pressure lowering effect The test subjects were given 730 mg of quercetin daily for almost a month and a reduction in systolic (−7 ± 2 mm Hg) and diastolic (−5 ± 2 mm Hg) blood pressure was observed in patients with high blood pressure. Further clinical studies are therefore recommended. https://pubmed.ncbi.nlm.nih.gov/17951477/

How do I recognize a high-quality product?

When buying, you should make sure that the product is 100% natural. The premium flower extract should come from the Japanese pagoda tree Sophora japonica and ideally have an extract ratio of 15:1. The water-alcohol extract used for production should be highly pure and contain no chemical solvents. Capsules can be perfectly integrated into your everyday life as a dietary supplement.

Legal Consumer Information

German and European law aims to protect consumers from allegedly misleading claims of effectiveness. The statements made here refer to the original Ayurvedic and TCM texts. This knowledge, which has been passed down for thousands of years, is based on experience passed down from generation to generation. It is not intended to claim that the products described here have an effect in the sense of Western medicine. All products are food supplements; they are not medications and have no medical effect. If you are ill and need medical care, please contact your doctor or pharmacist.