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-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 ) 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

Animal enzyme

O-methylated anthocyanidins

O-methylated flavanols

O-methylated flavanones

O-methylated flavanonols

O-methylated flavonols

of kaempferol of myricetin of quercetin other

O-methylated flavones

O-methylated isoflavones