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]

Isorhamnetin
Isorhamnetin structure
Isorhamnetin 3D structure
Names
IUPAC name
3,4′,5,7-Tetrahydroxy-3′-methoxyflavone
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
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.006.860 Edit this at Wikidata
KEGG
UNII
  • InChI=1S/C16H12O7/c1-22-11-4-7(2-3-9(11)18)16-15(21)14(20)13-10(19)5-8(17)6-12(13)23-16/h2-6,17-19,21H,1H3 ☒N
    Key: IZQSVPBOUDKVDZ-UHFFFAOYSA-N ☒N
  • InChI=1/C16H12O7/c1-22-11-4-7(2-3-9(11)18)16-15(21)14(20)13-10(19)5-8(17)6-12(13)23-16/h2-6,17-19,21H,1H3
    Key: IZQSVPBOUDKVDZ-UHFFFAOYAD
  • COC1=C(C=CC(=C1)C2=C(C(=O)C3=C(C=C(C=C3O2)O)O)O)O
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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Metabolism

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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).

Glycosides

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See also

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References

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  1. ^ Slimestad, R; Fossen, T; Vågen, IM (December 2007). "Onions: a source of unique dietary flavonoids". J. Agric. Food Chem. 55 (25): 10067–80. doi:10.1021/jf0712503. PMID 17997520.
  2. ^ Holland, Thomas M.; Agarwal, Puja; Wang, Yamin; Leurgans, Sue E.; Bennett, David A.; Booth, Sarah L.; Morris, Martha Clare (2020-01-29). "Dietary flavonols and risk of Alzheimer dementia". Neurology. 94 (16): e1749–e1756. doi:10.1212/WNL.0000000000008981. ISSN 0028-3878. PMC 7282875. PMID 31996451.
  3. ^ PMID 25544797 PMC4276397
  4. ^ Céspedes, Carlos L. (2006). "Antifungal and Antibacterial Activities of Mexican Tarragon (Tagetes lucida)". Journal of Agricultural and Food Chemistry. 54 (10): 3521–3527. doi:10.1021/jf053071w. PMID 19127719.
  5. ^ Abdala, 1999
  6. ^ Antunes-Ricardo M, Garcia-Cayuela T, Mendiola JA, Ibañez E, Gutierrez-Uribe JA, Cano MP, Guajardo-Flores D (November 2018). "Supercritical CO2 enzyme hydrolysis as a pretreatment for the release of isorhamnetin conjugates from Opuntia ficus-indica (L.) Mill". The Journal of Supercritical Fluids. 141: 21–28. doi:10.1016/j.supflu.2017.11.030. S2CID 103893093.
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