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 t ...

s on hydroxyl 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 ...

(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 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 t ...

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-me ...

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 substrate ...

Isoliquiritigenin 2'-O-methyltransferase In enzymology, an isoliquiritigenin 2'-O-methyltransferase () is an enzyme that catalysis, catalyzes the chemical reaction :S-adenosyl-L-methionine + isoliquiritigenin \rightleftharpoons S-adenosyl-L-homocysteine + 2'-O-methylisoliquiritigenin Th ...

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 In enzymology, a luteolin O-methyltransferase () is an enzyme that catalyzes the chemical reaction :S-adenosyl-L-methionine + 5,7,3',4'-tetrahydroxyflavone \rightleftharpoons S-adenosyl-L-homocysteine + 5,7,4'-trihydroxy-3'-methoxyflavone Thus, t ...

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 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

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, has been obtained from ''Plumbago capensis ''Plumbago auriculata'', the cape leadwort, blue plumbago or Cape p ...

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 ''Plumbago'' is a genus of 10–20 ...

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 A ...

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 of ...

* Peonidin * Petunidin * Pulchellidin *

Rosinidin Rosinidin is an ''O''-methylated anthocyanidin derived from Cyanidin. It is a pigment found in the flowers of ''Catharanthus roseus'' and, in lower concentration, in ''Primula rosea ''Primula rosea'', the rosy primrose, is a flowering plant sp ...

O-methylated flavanols

Meciadanol Meciadanol is a synthetic O-methylated flavanol. It is the 3-''O''-methylation of catechin. It inhibits histidine decarboxylase The enzyme histidine decarboxylase (, HDC) is transcribed on chromosome 15, region 21.2, and catalyzes the decarbo ...

(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 flavan ...

* 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 whic ...

O-methylated flavanonols

* Dihydrokaempferide

''O''-methylated flavonols

of kaempferol * Kaempferide of myricetin *

Annulatin Annulatin is an O-methylated flavonol found in the roots of ''Pteroxygonum giraldii ''Pteroxygonum giraldii'' is a species of flowering plant in the family Polygonaceae, endemic to the China, Chinese provinces of Gansu, Hebei, Henan, Hubei, Sh ...

Combretol Combretol is an O-methylated flavonol, a type of flavonoid. It is the 3,7,3',4',5'-O-methylation of myricetin and can be extracted from ''Combretum quadrangulare'' and from ''Rhodomyrtus tomentosa ''Rhodomyrtus tomentosa'' also known as rose my ...

Europetin Europetin is an O-methylated flavonol. It can be found in ''Plumbago europaea ''Plumbago europaea'', also known as the common leadwort, is a plant species in the genus ''Plumbago'' found in the Mediterranean Basin and Central Asia Central ...

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 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 billberries). It is one of the phenolic compounds present i ...

(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 4 ...

* Azaleatin * Isorhamnetin *

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''. It can also be synthesized. Ombuin 3-sulfate can be isolated from '' Flaveri ...

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

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 be ...

other * Eupatolitin * Natsudaidain

O-methylated flavones

Acacetin Acacetin is a 4′- ''O''-methylated flavone of the parent compound apigenin, found in ''Robinia pseudoacacia ''Robinia pseudoacacia'', commonly known in its native territory as black locust, is a medium-sized hardwood deciduous tree, belon ...

* 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 Oroxylin A is an O-methylated flavone, a chemical compound that can be found in the medicinal plants ''Scutellaria baicalensis'' and ''Scutellaria lateriflora'', and the ''Oroxylum indicum'' tree. It has demonstrated activity as a dopamine reupt ...

Sinensetin Sinensetin is a methylated flavone. It can be found in ''Orthosiphon stamineus'' and in orange oil Orange oil is an essential oil produced by cells within the rind of an orange fruit (''Citrus sinensis'' fruit). In contrast to most essential ...

Tangeritin Tangeretin is an O- polymethoxylated flavone that is found in tangerine and other citrus ''Citrus'' is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops ...

* 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 Biochanin A is an ''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 (''Cicer arietinum'' ...

Calycosin Calycosin is an ''O''-methylated isoflavone. It can be isolated from ''Astragalus membranaceus'' Bge. var. ''mongholicus'' and ''Trifolium pratense'' L. (red clover). Biosynthesis Isoflavone 3′-hydroxylase uses formononetin Formononetin is ...

* 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 A phytoestrogen is a plant-derived xenoestrogen (see estrogen) not generated within the endocrine sy ...

* Irigenin *

5-O-methylgenistein 5-''O''-Methylgenistein is an O-methylated isoflavone. It can be found in '' Ormosia excelsa'', a tropical legume. References O-methylated isoflavones {{aromatic-stub ...

Pratensein Pratensein is an O-methylated isoflavone, a type of flavonoid. It can be found in ''Trifolium pratense'' (red clover) and can have effects for the prevention of atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis in w ...

* 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 Tectoridin is an isoflavone Isofla ...

References

{{DEFAULTSORT:O-Methylated Flavonoid O-methylation