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 In the chemical sciences, methylation denotes the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These ...

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 hydrox ...

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

Enzymes

O-methylated flavonoids formation implies the presence of specific

O-methyltransferase An O-methyltransferase (OMT) is a type of methyltransferase enzyme transferring a methyl group on a molecule. Examples are : * Acetylserotonin O-methyltransferase * Apigenin 4'-O-methyltransferase * Caffeate O-methyltransferase * Caffeoyl-CoA O-m ...

(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'') 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 *

8-hydroxyquercetin 8-O-methyltransferase In enzymology, a 8-hydroxyquercetin 8-O-methyltransferase () is an enzyme that catalyzes the chemical reaction :S-adenosyl-L-methionine + 3,5,7,8,3',4'-hexahydroxyflavone \rightleftharpoons S-adenosyl-L-homocysteine + 3,5,7,3',4'-pentahydroxy-8-m ...

Isoflavone 4'-O-methyltransferase In enzymology, an isoflavone 4'-O-methyltransferase () is an enzyme that catalyzes the chemical reaction :S-adenosyl-L-methionine + an isoflavone \rightleftharpoons S-adenosyl-L-homocysteine + a 4'-O-methylisoflavone Thus, the two substrates of ...

Isoflavone 7-O-methyltransferase In enzymology, an isoflavone 7-O-methyltransferase () is an enzyme that catalyzes the chemical reaction :S-adenosyl-L-methionine + a 7-hydroxyisoflavone \rightleftharpoons S-adenosyl-L-homocysteine + a 7-methoxyisoflavone Thus, the two substrat ...

* Isoliquiritigenin 2'-O-methyltransferase *

Isoorientin 3'-O-methyltransferase In enzymology, an isoorientin 3'-O-methyltransferase () is an enzyme that catalyzes the chemical reaction :S-adenosyl-L-methionine + isoorientin \rightleftharpoons S-adenosyl-L-homocysteine + isoscoparin Thus, the two substrates of this enzyme ...

Kaempferol 4'-O-methyltransferase In enzymology, a kaempferol 4'-O-methyltransferase () is an enzyme that catalyzes the chemical reaction :S-adenosyl-L-methionine + kaempferol \rightleftharpoons S-adenosyl-L-homocysteine + kaempferide Thus, the two substrates of this enzyme are ...

* Luteolin O-methyltransferase *

Methylquercetagetin 6-O-methyltransferase In enzymology, a methylquercetagetin 6-O-methyltransferase () is an enzyme that catalyzes the chemical reaction :S-adenosyl-L-methionine + 5,6,3',4'-tetrahydroxy-3,7-dimethoxyflavone \rightleftharpoons S-adenosyl-L-homocysteine + 5,3',4'-trihydrox ...

3-methylquercetin 7-O-methyltransferase In enzymology, a 3-methylquercetin 7-O-methyltransferase () is an enzyme that catalyzes the chemical reaction :S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxy-3-methoxyflavone \rightleftharpoons S-adenosyl-L-homocysteine + 5,3',4'-trihydroxy-3,7- ...

* Myricetin O-methyltransferase * Quercetin 3-O-methyltransferase * Vitexin 2"-O-rhamnoside 7-O-methyltransferase

Animal enzyme

* Catechol-O-methyl transferase

O-methylated anthocyanidins

* 5-Desoxy-malvidin * Capensinidin * Europinidin * Hirsutidin *

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 *

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 redberries includin ...

* Pulchellidin * Rosinidin *

O-methylated flavanols

* Meciadanol (3-O'methyl catechin)

O-methylated flavanones

Hesperetin Hesperetin is the 4'-methoxy derivative of eriodictyol, a flavanone. Hesperetin's 7-O-glycoside, hesperidin, is a naturally occurring flavanon-glycoside, the main flavonoid in lemons and sweet oranges. Hesperetin (and naringenin, the parent f ...

* Homoeriodictyol * Isosakuranetin *

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''. Glycosides Sakuranin is the 5-O-glucoside of sakuranet ...

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 which ...

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 billberries). 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 dietar ...

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 billberries). 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. It can be found in '' Croton schiedeanus''. It can also be synthetized. Biosynthesis The enzyme 3,7-dimethylquercetin ...

Azaleatin Azaleatin is a chemical compound. It is an O-methylated flavonol, a type of flavonoid. It was first isolated from the flowers of ''Rhododendron mucronatum'' in 1956 and has since been recorded in forty-four other Rhododendron species, in ''Plumbag ...

Isorhamnetin Isorhamnetin is an O-methylated flavon-ol from the class of flavonoids. A common food source of this 3'-methoxylated derivative of quercetin and its glucoside conjugates are pungent yellow or red onions, in which it is a minor pigment, quercetin ...

Ombuin Ombuin is an O-methylated flavonol, a type of flavonoid. It is the 4',7-O-methyl derivative of quercetin. Ombuin can be found in species of the genus ''Erythroxylum ''Erythroxylum'' (''Erythroxylon'') is a genus of tropical flowering plants i ...

Pachypodol Pachypodol is an O-methylated flavonol, a type of chemical compound. It can be isolated from '' Pachypodanthium confine'', from leaves of '' Agastache rugosa, (Korean mint)'', Latin denomination of part of plant : Agastache folium . References ...

* 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 endemic to Sri Lanka. Metabolism The enzyme 3-methylquercetin 7-''O''-methyltransferase uses ''S''-adenosyl m ...

Rhamnetin Rhamnetin is an O-methylated flavonol, 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 of xanthorh ...

Tamarixetin Tamarixetin is an O-methylated flav-on-ol, a naturally occurring flavonoid. See also * Isorhamnetin, the 3'-methyl analog * List of antioxidants in food * List of phytochemicals in food While there is ample evidence to indicate the health b ...

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 i ...

O-methylated flavones

* Acacetin * Chrysoeriol * Diosmetin * Nepetin *

Nobiletin Nobiletin is a flavonoid isolated from citrus peels. It is an ''O''-methylated flavone that has the activity to rescue bulbectomy-induced memory impairment. Potential pharmacology Nobiletin was found to potentially inhibit cartilage degradation ...

* Oroxylin-A * Sinensetin * Tangeritin * Thevetiaflavone *

Wogonin Wogonin is an O-methylated flavone, a flavonoid-like chemical compound which is found in ''Scutellaria baicalensis''. The glycosides of wogonin are known as wogonosides. For example, oroxindin is a wogonin glucuronide isolated from '' Oroxylum ...

O-methylated isoflavones

* Biochanin A * Calycosin * Formononetin * Glycitein *

Irigenin Irigenin is an O-methylated isoflavone, a type of flavonoid. It can be isolated from the rhizomes of the leopard lily ('' Belamcanda chinensis''), and ''Iris kemaonensis''. Jiaju Zhou, Guirong Xie and Xinjian Yan Glycosides Iridin is the 7-gl ...

5-O-methylgenistein 5-''O''-Methylgenistein is an O-methylated isoflavone. It can be found in ''Ormosia excelsa ''Ormosia excelsa'' is a plant species in the genus ''Ormosia'', a tropical legume. ''Ormosia excelsa'' produces the O-methylated isoflavone 5-O-meth ...

* Pratensein * Prunetin * Psi-tectorigenin * Retusin *

Tectorigenin Tectorigenin is an O-methylated isoflavone, a type of flavonoid. It can be isolated from leopard lily (''Belamcanda chinensis''), in ''Iris unguicularis'' or '' Pueraria thunbergiana''. Glycosides Tectoridin is the 7-glucoside A glucoside i ...

References

{{DEFAULTSORT:O-Methylated Flavonoid O-methylation