Kversetiini

Kversetiini, commonly known as quercetin in many languages, is a flavonol, a type of flavonoid widely distributed in the plant kingdom. Its chemical formula is C15H10O7 and its IUPAC name is 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-1-benzopyran-4-one. In plants, kversetiini frequently occurs as glycosides, including quercetin-3-O-glucoside and rutin (quercetin-3-O-rutinoside).

Dietary sources include onions, apples, berries, grapes, citrus fruits, tea and wine, and various leafy vegetables. Quercetin is produced in plants via the phenylpropanoid pathway and can be converted to several glycosides that influence its solubility and storage in plant tissues.

Biological activity is dominated by antioxidant and anti-inflammatory effects observed in vitro and in animal studies; however, human evidence for specific health benefits remains mixed. Bioavailability is limited and quercetin is absorbed incompletely, undergoing extensive metabolism to glucuronide and sulfate conjugates and, in part, to metabolites produced by gut microbiota.

Uses and safety: kversetiini is commonly consumed as part of the diet and is marketed in supplement form as a nutraceutical. It is generally considered safe at typical dietary intakes, but high-dose supplementation may cause adverse effects in some individuals and can interact with certain medications. No formal daily requirement has been established.

See also: Flavonoids; Quercetin glycosides; Kaempferol; Rutin.