Quercitrin is a

glycoside In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. ...

formed from the

flavonoid Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...

quercetin Quercetin is a plant flavonol from the flavonoid group of polyphenols. It is found in many fruits, vegetables, leaves, seeds, and grains; capers, red onions, and kale are common foods containing appreciable amounts of it. It has a bitter flavor a ...

and the

deoxy sugar Deoxy sugars are sugars that have had a hydroxyl group replaced with a hydrogen atom. Examples include: * Deoxyribose, or 2-deoxy-D-ribose, a constituent of DNA * Fucose, or 6-deoxy-L-galactose, main component of fucoidan of brown algae, and p ...

rhamnose Rhamnose (Rha, Rham) is a naturally occurring deoxy sugar. It can be classified as either a methyl-pentose or a 6-deoxy-hexose. Rhamnose predominantly occurs in nature in its L-form as L-rhamnose (6-deoxy-L-mannose). This is unusual, since most o ...

. Austrian chemist

Heinrich Hlasiwetz Heinrich Hlasiwetz (7 April 1825 – 7 October 1875) was an Austrian chemist born in Reichenberg, Bohemia. Son of a pharmacist, he studied at the University of Jena, where his instructors included Johann Wolfgang Döbereiner (1780-1849), H ...

(1825-1875) is remembered for his chemical analysis of quercitrin.

Occurrence

Quercitrin is a constituent of the dye

quercitron Quercitron is a yellow natural dye obtained from the bark of the Eastern Black Oak (''Quercus velutina''), a forest tree indigenous in North America. It was formerly called Dutch pink, English pink, or Italian pink. The name is a shortened fo ...

. It can be found in Tartary buckwheat (''

Fagopyrum tataricum ''Fagopyrum tataricum'', also known as Tartary buckwheat, green buckwheat, ku qiao, Tatar buckwheat, or bitter buckwheat, is a domesticated food plant in the genus ''Fagopyrum'' in the family Polygonaceae. With another species in the same genus, ...

'') and in oaks species like the North American white oak (''

Quercus alba An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably '' ...

'') and English oak (''

Quercus robur ''Quercus robur'', commonly known as common oak, pedunculate oak, European oak or English oak, is a species of flowering plant in the beech and oak family, Fagaceae. It is a large tree, native plant, native to most of Europe west of the Caucasus ...

'').Analysis of oak tannins by liquid chromatography-electrospray ionisation mass spectrometry. Pirjo Mämmelä, Heikki Savolainen, Lasse Lindroos, Juhani Kangas and Terttu Vartiainen, Journal of Chromatography A, Volume 891, Issue 1, 1 September 2000, Pages 75-83, It is also found in ''

Nymphaea odorata ''Nymphaea odorata'', also known as the American white waterlily, fragrant water-lily, beaver root, fragrant white water lily, white water lily, sweet-scented white water lily, and sweet-scented water lily, is an aquatic plant belonging to the g ...

'' or ''

Taxillus kaempferi ''Taxillus kaempferi'' () is a parasitic plant A parasitic plant is a plant that derives some or all of its nutritional requirements from another living plant. They make up about 1% of angiosperms and are found in almost every biome. All para ...

''.The constituents of Taxillus kaempferi and the host, Pinus thunbergii. I. Catechins and flavones of Taxillus kaempferi. Konishi T, Nishio T, Kiyosawa S, Fujiwara Y and Konoshima T, Yakugaku Zasshi., February 1996, volume 116, issue 2, pages 148-157 (article in Japanese),

Metabolism

The enzyme

quercitrinase In enzymology, a quercitrinase () is an enzyme that catalyzes the chemical reaction :quercitrin + H2O \rightleftharpoons L-rhamnose + quercetin Thus, the two substrates of this enzyme are quercitrin and H2O, whereas its two products are L- rh ...

catalyzes the chemical reaction between quercitrin and H₂O to yield

L-rhamnose Rhamnose (Rha, Rham) is a naturally occurring deoxy sugar. It can be classified as either a methyl-pentose or a 6-deoxy-hexose. Rhamnose predominantly occurs in nature in its L-form as L-rhamnose (6-deoxy-L-mannose). This is unusual, since most o ...

and quercetin.

References

Quercetin glycosides Flavonol rhamnosides {{aromatic-stub