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[edit]
O-methylated flavonoids formation implies the presence of specific O-methyltransferase (OMT) enzymes which accept a variety of substrates.[1] Those enzymes mediate the O-methylation on a specific hydroxyl group, like on 4' (example in Catharanthus roseus[2]) or 3' (example in rice[3]) 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.[4]
Plant enzymes[edit]
- Apigenin 4'-O-methyltransferase
- 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
- Vitexin 2"-O-rhamnoside 7-O-methyltransferase
Animal enzyme[edit]
O-methylated anthocyanidins[edit]
- 5-Desoxy-malvidin
- Capensinidin
- Europinidin
- Hirsutidin
- Malvidin
- Peonidin
- Petunidin
- Pulchellidin
- Rosinidin
- [5]
O-methylated flavanols[edit]
- Meciadanol (3-O'methyl catechin)
O-methylated flavanones[edit]
O-methylated flavanonols[edit]
O-methylated flavonols[edit]
of kaempferol
of myricetin
- Annulatin
- Combretol
- Europetin
- Laricitrin (3'-O-Dimethylmyricetin)
- 5-O-methylmyricetin
- Syringetin (3',5'-O-Dimethylmyricetin)
of quercetin
- Ayanin
- Azaleatin
- Isorhamnetin
- Ombuin
- Pachypodol
- Retusin (quercetin-3,7,3',4'-tetramethyl ether)
- Rhamnazin
- Rhamnetin
- Tamarixetin
other
O-methylated flavones[edit]
- Acacetin
- Chrysoeriol
- Diosmetin
- Nepetin
- Nobiletin
- Oroxylin-A
- Sinensetin
- Tangeritin
- Thevetiaflavone
- Wogonin
O-methylated isoflavones[edit]
- Biochanin A
- Calycosin
- Formononetin
- Glycitein
- Irigenin
- 5-O-methylgenistein
- Pratensein
- Prunetin
- Psi-tectorigenin
- Retusin
- Tectorigenin
See also[edit]
References[edit]
- ^ Kim, Dae Hwan; Kim, Bong-Gyu; Lee, Youngshim; Ryu, Ji Young; Lim, Yoongho; Hur, Hor-Gil; Ahn, Joong-Hoon (2005). "Regiospecific methylation of naringenin to ponciretin by soybean O-methyltransferase expressed in Escherichia coli". Journal of Biotechnology. 119 (2): 155–62. doi:10.1016/j.jbiotec.2005.04.004. PMID 15961179.
- ^ Schroder, G; Wehinger, E; Lukacin, R; Wellmann, F; Seefelder, W; Schwab, W; Schröder, J (2004). "Flavonoid methylation: a novel 4′-O-methyltransferase from Catharanthus roseus, and evidence that partially methylated flavanones are substrates of four different flavonoid dioxygenases". Phytochemistry. 65 (8): 1085–94. doi:10.1016/j.phytochem.2004.02.010. PMID 15110688.
- ^ Kim, Bong-Gyu; Lee, Youngshim; Hur, Hor-Gil; Lim, Yoongho; Ahn, Joong-Hoon (2006). "Flavonoid 3′-O-methyltransferase from rice: CDNA cloning, characterization and functional expression". Phytochemistry. 67 (4): 387–94. doi:10.1016/j.phytochem.2005.11.022. PMID 16412485.
- ^ Brunet, Gunter; Ibrahim, Ragai K. (1980). "O-methylation of flavonoids by cell-free extracts of calamondin orange". Phytochemistry. 19 (5): 741–6. doi:10.1016/0031-9422(80)85102-8.
- ^ Harborne, J.B. (1967). "Comparative biochemistry of the flavonoids-IV.: Correlations between chemistry, pollen morphology and systematics in the family plumbaginaceae". Phytochemistry. 6 (10): 1415–28. doi:10.1016/S0031-9422(00)82884-8.