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Isorhamnetin

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. Pears, olive oil, wine and tomato sauce are rich in isorhamnetin. 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. Others sources include the spice, herbal medicinal and psychoactive Mexican tarragon (Tagetes lucida), which is described as accumulating isorhamnetin and its 7-O-glucoside derivate. Nopal is also a good source of isorhamnetin, which can be extracted by supercritical fluid extraction assisted by enzymes.

Last revised
Jul 22, 2026
Read time
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Length
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Citations
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Source
Wikipedia ↗
Isorhamnetin
Isorhamnetin structure
Isorhamnetin structure source ↗
Isorhamnetin 3D structure
Isorhamnetin 3D structure source ↗
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
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 X markN
    Key: IZQSVPBOUDKVDZ-UHFFFAOYSA-N X markN
  • 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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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 medicinal4 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

Biosynthesis and metabolism

The enzyme luteolin O-methyltransferase uses S-adenosyl methionine to methylate the flavanol, quercetin, giving isorhamnetin.78

The enzyme 3-methylquercetin 7-O-methyltransferase further methylates isorhamnetin to produce rhamnazin.9

Isorhamnetin is an inhibitor of CYP1B1.10

Glycosides

  • Isorhamnetin-3-O-rutinoside-7-O-glucoside
  • Isorhamnetin-3-O-rutinoside-4'-O-glucoside
  • Narcissin (Isorhamnetin-3-O-rutinoside)
See also

See also

References

References

  1. Slimestad, R; Fossen, T; Vågen, IM (December 2007). "Onions: a source of unique dietary flavonoids". J. Agric. Food Chem. 55 (25): 10067–80. Bibcode:2007JAFC...5510067S. 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. Bibcode:2006JAFC...54.3521C. 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.
  7. Muzac, Ingrid; Wang, Jing; Anzellotti, Dominique; Zhang, Hong; Ibrahim, Ragai K. (2000). "Functional Expression of an Arabidopsis cDNA Clone Encoding a Flavonol 3′-O-Methyltransferase and Characterization of the Gene Product". Archives of Biochemistry and Biophysics. 375 (2): 385–388. doi:10.1006/abbi.1999.1681. PMID 10700397.
  8. Liu, Weixin; Feng, Yi; Yu, Suhang; Fan, Zhengqi; Li, Xinlei; Li, Jiyuan; Yin, Hengfu (2021). "The Flavonoid Biosynthesis Network in Plants". International Journal of Molecular Sciences. 22 (23) 12824. doi:10.3390/ijms222312824. PMC 8657439. PMID 34884627.
  9. De Luca V, Ibrahim RK (1985). "Enzymatic synthesis of polymethylated flavonols in Chrysosplenium americanum. I. Partial purification and some properties of S-adenosyl-L-methionine:flavonol 3-, 6-, 7-, and 4'-O-methyltransferases". Arch. Biochem. Biophys. 238 (2): 596–605. doi:10.1016/0003-9861(85)90205-X. PMID 3994393.
  10. Li, Fei; Zhu, Weifeng; Gonzalez, Frank J (October 2017). "Potential role of CYP1B1 in the development and treatment of metabolic diseases". Pharmacology & Therapeutics. 178: 18–30. doi:10.1016/j.pharmthera.2017.03.007. PMC 5600638. PMID 28322972.
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