The O-methylated flavonoids or methoxyflavonoids are

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 ...

s with

methylation Methylation, in the chemistry, chemical sciences, is the addition of a methyl group on a substrate (chemistry), substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replac ...

s on

hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...

groups (

methoxy In organic chemistry, a methoxy group is the functional group consisting of a methyl group bound to oxygen. This alkoxy group has the formula . On a benzene ring, the Hammett equation classifies a methoxy substituent at the ''para'' position a ...

bonds). O-methylation has an effect on the solubility of flavonoids.

Enzymes

O-methylated flavonoids formation implies the presence of specific O-methyltransferase (OMT) enzymes which accept a variety of substrates. Those enzymes mediate the O-methylation on a specific hydroxyl group, like on 4' (example in ''

Catharanthus roseus ''Catharanthus roseus'', commonly known as bright eyes, Cape periwinkle, graveyard plant, Madagascar periwinkle, old maid, pink periwinkle, rose periwinkle, is a perennial species of flowering plant in the family Apocynaceae. It is native and en ...

'') or 3' (example in rice) positions. Those positions can be ortho, meta, para and there can be a special 3-O-methyltransferase for the 3-OH position. Calamondin orange ('' Citrus mitis'') exhibits all of those activities.

Plant enzymes

Apigenin 4'-O-methyltransferase In enzymology, an apigenin 4'-O-methyltransferase () is an enzyme that catalyzes the chemical reaction :S-adenosyl-L-methionine + 5,7,4'-trihydroxyflavone \rightleftharpoons S-adenosyl-L-homocysteine + 4'-methoxy-5,7-dihydroxyflavone Thus, the tw ...

* 8-hydroxyquercetin 8-O-methyltransferase * Isoflavone 4'-O-methyltransferase * Isoflavone 7-O-methyltransferase * Isoliquiritigenin 2'-O-methyltransferase * Isoorientin 3'-O-methyltransferase * Kaempferol 4'-O-methyltransferase * Luteolin O-methyltransferase * Methylquercetagetin 6-O-methyltransferase * 3-methylquercetin 7-O-methyltransferase * Myricetin O-methyltransferase *

Quercetin 3-O-methyltransferase In enzymology, a quercetin 3-O-methyltransferase () is an enzyme that catalyzes the chemical reaction :S-adenosyl-L-methionine + 3,5,7,3',4'-pentahydroxyflavone \rightleftharpoons S-adenosyl-L-homocysteine + 3-methoxy-5,7,3',4'-tetrahydroxyflavone ...

* Vitexin 2"-O-rhamnoside 7-O-methyltransferase

Animal enzyme

Catechol-O-methyl transferase Catechol-''O''-methyltransferase (COMT; ) is one of several enzymes that degrade catecholamines (neurotransmitters such as dopamine, epinephrine, and norepinephrine), catecholestrogens, and various drugs and substances having a catechol struc ...

O-methylated anthocyanidins

* 5-Desoxy-malvidin *

Capensinidin Capensinidin (Cp) is an O-methylated anthocyanidin. It is a water-soluble, blue-red plant dye. It is a 5-methoxy analog of malvidin Malvidin is an O-methylated anthocyanidin, the 3',5'-methoxy derivative of delphinidin. As a primary plant pig ...

Europinidin Europinidin (Eu) is an O-methylated anthocyanidin. It is a water-soluble, bluish red plant dye. It is a rare O-methylated flavonoid, a derivative of delphinidin. It can be found in some species of ''Plumbago'' and ''Ceratostigma''. References

Hirsutidin Hirsutidin is an O-methylated anthocyanidin, a chemical compound belonging to the anthocyanins. It can be found in '' Catharanthus roseus'' (Madagascar periwinkle) where it is the prominent compound in petals and can also be found in callus culture ...

Malvidin Malvidin is an O-methylated anthocyanidin, the 3',5'-methoxy derivative of delphinidin. As a primary plant pigment, its glycosides are highly abundant in nature. Natural occurrences Malvidin is responsible for the blue color found in petals ...

Peonidin Peonidin is an O-methylated anthocyanidin derived from Cyanidin, and a primary plant pigment. Peonidin gives purplish-red hues to flowers such as the peony, from which it takes its name, and roses. It is also present in some blue flowers, such as ...

Petunidin Petunidin (Pt), like Europinidin and Malvidin, is derived from Delphinidin and is an O-methylated anthocyanidin of the 3-hydroxy type. It is a natural organic compound, a dark-red or purple water-soluble pigment found in many red berries includi ...

Pulchellidin Pulchellidin (Pl) is an ''O''-methylated anthocyanidin. It is a blue-red plant pigment. It can be found in '' Plumbago pulchella''. Glycosides * Pulchellidin 3-rhamnoside (molecular formula : C22H23O11, exact mass : 463.124036578) is reported in ...

* Rosinidin *

O-methylated flavanols

* Meciadanol (3-O'methyl catechin)

O-methylated flavanones

Hesperetin Hesperetin is the 4'-methoxy derivative of eriodictyol, a flavanone. The 7-''O''-glycoside of hesperetin, hesperidin, is a naturally occurring flavanone-glycoside, the main flavonoid in grapefruits, lemons, and sweet oranges. Glycosides Vario ...

Homoeriodictyol Homoeriodictyol is a bitter-masking flavanone extracted from Yerba Santa ('' Eriodictyon californicum'') a plant growing in America. Homoeriodictyol (3`-methoxy-4`,5,7-trihydroxyflavanone) is one of the 4 flavanones identified by Symrise in thi ...

Isosakuranetin Isosakuranetin, an O-methylated flavonoid, is the 4'-methoxy derivative of naringenin, a flavanone. Didymin, a disaccharide of isosakuranetin, occur e.g. in sweet orange, blood orange and mandarin. Isosakuranetin is a potent inhibitor of TRPM3 cha ...

Sakuranetin Sakuranetin is a flavan-on, the 7-methoxy derivative of naringenin, found in Polymnia fruticosa and rice, where it acts as a phytoalexin against spore germination of '' Pyricularia oryzae''. __TOC__ Glycosides Sakuranin is the 5-O-glucoside of ...

Sterubin Sterubin (7-methoxy-3',4',5-trihydroxyflavanone) is a bitter-masking flavanone extracted from Yerba Santa ('' Eriodictyon californicum'') a plant growing in America. Sterubin is one of the four flavanones identified by Symrise in this plant whi ...

O-methylated flavanonols

* Dihydrokaempferide

''O''-methylated flavonols

of kaempferol *

Kaempferide Kaempferide is an ''O''-methylated flavonol, a type of chemical compound. It can be found in ''Kaempferia galanga'' (aromatic ginger). It has been noted to inhibit pancreatic cancer growth by blockading an EGFR-related pathway. Metabolism Th ...

of myricetin * Annulatin * Combretol * Europetin *

Laricitrin Laricitrin is an ''O''-methylated flavonol, a type of flavonoid. It is found in red grape (absent in white grape) and in '' Vaccinium uliginosum'' (bog bilberries). It is one of the phenolic compounds present in wine. Metabolism Laricitrin is ...

(3'-O-Dimethylmyricetin) *

5-O-methylmyricetin 5-''O''-Methylmyricetin is an ''O''-methylated flavonol, a type of flavonoid. It is the 5-''O''-methyl derivative of myricetin Myricetin is a member of the flavonoid class of polyphenolic compounds, with antioxidant properties. Common dietary ...

Syringetin Syringetin is an ''O''-methylated flavonol, a type of flavonoid. It is found in red grape (absent in white grape), in '' Lysimachia congestiflora'' and in '' Vaccinium uliginosum'' (bog bilberries). It is one of the phenolic compounds present in ...

(3',5'-O-Dimethylmyricetin) of quercetin *

Ayanin Ayanin is an ''O''-methylated flavonol, a type of flavonoid. It is the 3,7,4'-tri-''O''-methylated derivative of quercetin Quercetin is a plant flavonol from the flavonoid group of polyphenols. It is found in many fruits, vegetables, leaves, s ...

* Azaleatin *

Isorhamnetin Isorhamnetin is an O-methylated flavon-ol from the class of 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, a ...

* Ombuin *

Pachypodol Pachypodol is a chemical compound classified as an O-methylated flavonol. It can be isolated from a variety of plants including '' Calycopteris floribunda'', '' Pogostemon cablin'', and '' Croton ciliatoglanduliferus''. References O-methy ...

* Retusin (quercetin-3,7,3',4'-tetramethyl ether) *

Rhamnazin Rhamnazin is an ''O''-methylated flavonol, a type of chemical compound. It can be found in '' Rhamnus petiolaris'', a buckthorn plant native to Iraq, Lebanon, Syria, and Turkey. Metabolism The enzyme 3-methylquercetin 7-''O''-methyltransferase ...

Rhamnetin Rhamnetin is an O-methylated flavonoid, a type of chemical compound. It can be isolated from cloves. The structure of the molecule was discovered by Austrian chemist Josef Herzig (1853–1924). Glycosides Rhamnetin is the aglycone An agly ...

* Tamarixetin other * Eupatolitin *

Natsudaidain Natsudaidain is an O-methylated flavonol, a type of chemical compound. It can be isolated from Citrus plants (Rutaceae). The name of the molecule comes from '' Citrus natsudaidai'' (Natsumikan, lit. "summer tangerine"), a fruit of Japan developed ...

O-methylated flavones

* Acacetin * Chrysoeriol * Diosmetin * Nepetin * Nobiletin * Oroxylin-A * Sinensetin * Tangeritin * Thevetiaflavone * Wogonin

O-methylated isoflavones

Biochanin A Biochanin A is an O-methylated isoflavone, ''O''-methylated isoflavone. It is a natural organic compound in the class of phytochemicals known as flavonoids. Biochanin A can be found in red clover in soy, in alfalfa sprouts, in peanuts, in chickpea ...

* Calycosin * Formononetin *

Glycitein Glycitein is an O-methylated isoflavone which accounts for 5-10% of the total isoflavones in soy food products. Glycitein is a phytoestrogen with weak estrogenic activity, comparable to that of the other soy isoflavones. Glycitin (glycitein 7-' ...

* Irigenin *

5-O-methylgenistein 5-''O''-Methylgenistein is an O-methylated isoflavone The O-methylated flavonoids or methoxyflavonoids are flavonoids with methylations on hydroxyl groups (methoxy bonds). O-methylation has an effect on the solubility of flavonoids. Enzymes O-me ...

* Pratensein * Prunetin * Psi-tectorigenin * Retusin * Tectorigenin

References

{{DEFAULTSORT:O-Methylated Flavonoid O-methylation