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-3,4'-diglucoside and quercetin-4'-glucoside and the aglycone quercetin being the major pigments.[1] Pears, olive oil, wine and tomato sauce are rich in isorhamnetin.[2] Almond skin is a rich source of isorhamnetin-3-O-rutinoside and isorhamnetin-3-O-glucoside, in some cultivars they comprise 75% of the polyphenol content, the total of which can exceed 10 mg/100 gram almond.[3] Others sources include the spice, herbal medicinal[4] and psychoactive Mexican tarragon (Tagetes lucida), which is described as accumulating isorhamnetin and its 7-O-glucoside derivate.[5] Nopal (Opuntia ficus-indica (L.)) is also a good source of isorhamnetin, which can be extracted by supercritical fluid extraction assisted by enzymes.[6]
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IUPAC name
3,4′,5,7-Tetrahydroxy-3′-methoxyflavone
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Systematic IUPAC name
3,5,7-Trihydroxy-2-(4-hydroxy-3-methoxyphenyl)-4H-1-benzopyran-4-one | |
Other names
3-methylquercetin
3-Methylquercetin Isorhamnetol isorhamentin isorhamnetine iso-rhamnetin 3'-Methoxyquercetin | |
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3D model (JSmol)
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ChEBI |
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ChemSpider |
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ECHA InfoCard | 100.006.860 |
KEGG |
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PubChem CID
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UNII |
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CompTox Dashboard (EPA)
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Properties | |
C16H12O7 | |
Molar mass | 316.26 g/mol |
Melting point | 307 °C (585 °F; 580 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
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The enzyme quercetin 3-O-methyltransferase uses S-adenosyl methionine and quercetin to produce S-adenosylhomocysteine and isorhamnetin.
The enzyme 3-methylquercetin 7-O-methyltransferase uses S-adenosyl methionine and 5,7,3',4'-tetrahydroxy-3-methoxyflavone (isorhamnetin) to produce S-adenosylhomocysteine and 5,3',4'-trihydroxy-3,7-dimethoxyflavone (rhamnazin).