Fagopyrin

Last updated
Fagopyrin
Fagopyrin.svg
Fagopyrin 3D ball.png
Names
IUPAC name
1,3,4,6,8,13-Hexahydroxy-10,11-dimethyl-2,5-di(piperidin-2-yl)fenantro[1,10,9,8-opqra]peryleen-7,14-dion
Identifiers
3D model (JSmol)
ChemSpider
PubChem CID
  • InChI=1S/C40H34N2O8/c1-13-11-17(43)23-25-19(13)20-14(2)12-18(44)24-26(20)28-27(25)29-31(35(45)21(15-7-3-5-9-41-15)37(47)33(29)39(23)49)32-30(28)34(40(24)50)38(48)22(36(32)46)16-8-4-6-10-42-16/h11-12,15-16,41-48H,3-10H2,1-2H3
    Key: ROFJUMITFMRBRF-UHFFFAOYSA-N
  • O=C1C2=C(C3=C(O)C(C4CCCCN4)=C2O)C(C5=C6C(C)=CC(O)=C15)=C7C(C3=C(O)C(C8NCCCC8)=C9O)=C9C(C%10=C7C6=C(C)C=C%10O)=O
Properties
C40H34N2O8
Molar mass 670.718 g·mol−1
AppearanceRed pigment
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Fagopyrin is a phototoxic substance found in the flowers of buckwheat (Fagopyrum esculentum). [1] Their chemical structure contains a naphthodianthrone skeleton similar to that of hypericin. [2] After exposure, fagopyrin can cause sensitivity to light, also called fagopyrism, an itchy skin rash. [3]

Contents

History and occurrence

The substance was isolated from flowers of the red-flowering genotype of buckwheat in 1941, and its chemical structure, which is derived from hypericin, was first described in 1979. [4] Within the edible parts of the plant, it is found exclusively in the brown fruit husk of buckwheat grains. [5]

Fagopyrin is located almost exclusively in the cotyledons of the buckwheat herb.

Structure

True buckwheat Fagopyrum esculentum kz14.jpg
True buckwheat

Recent literature describes several variants of fagopyrin, referred to as fagopyrins A to F. They differ in methylation at positions C-10 and C-11 and contain piperidineyl or pyrrolidineyl residues at C-2 and C-5. [6]

Biosynthesis and properties

The biosynthetic precursor of fagopyrin is protofagopyrin. This proto-compound converts under the influence of light by cyclization into fagopyrin, which is lipophilic and cannot be extracted with water. The content of fagopyrin in tea preparations is generally below the detection limit (<0.01%). [7] [8]

A solution of fagopyrin in pyridine exhibits a red color. [9]

References

  1. ↑ Brockmann, Hans; Weber, Erhard; Sander, Elsbeth (1950). "Fagopyrin, ein photodynamischer Farbstoff aus Buchweizen (Fagopyrum esculentum)". Die Naturwissenschaften. 37 (2): 43. Bibcode:1950NW.....37...43B. doi:10.1007/BF00645366. S2CID   29975083.
  2. ↑ Tavčar Benković, Eva; Žigon, Dušan; Friedrich, Miha; Plavec, Janez; Kreft, Samo (2014). "Isolation, analysis and structures of phototoxic fagopyrins from buckwheat". Food Chemistry. 143: 432–439. doi:10.1016/j.foodchem.2013.07.118. PMID   24054263.
  3. ↑ Kreft, S.; Janeš, D.; Kreft, I. (2013). "The content of fagopyrin and polyphenols in common and tartary buckwheat sprouts". Acta Pharmaceutica. 63 (4): 553–60. doi: 10.2478/acph-2013-0031 . PMID   24451079.
  4. ↑ Hornyák, Marta; Kula-Maximenko, Monika; Miszalski, Zbigniew; Nilsson, Anna; Andrén, Per E.; Göransson, Ulf; Slazak, Blazej (2025). "Distribution of photosensitive fagopyrin in buckwheat flowers and its potential biological relevance". Scientific Reports. 15 (1) 36279. Bibcode:2025NatSR..1536279H. doi:10.1038/s41598-025-20116-4. PMC   12533014 . PMID   41102249.
  5. ↑ Andreas Montag (2023), [ , p. 247, at Google Books Pflanzen und Haut Dermatologisch bedeutsame Abwehrstrategien der Pflanzen in Europa], Springer-Verlag, p. 247, ISBN   978-3-662-63014-3 {{citation}}: Check |url= value (help)
  6. ↑ Tavčar Benković, Eva; Žigon, Dušan; Friedrich, Miha; Plavec, Janez; Kreft, Samo (2014). "Isolation, analysis and structures of phototoxic fagopyrins from buckwheat". Food Chemistry. 143: 432–439. doi:10.1016/j.foodchem.2013.07.118. PMID   24054263..
  7. ↑ Rudolf Hänsel, Otto Sticher (2006), [ , p. 1216, at Google Books Pharmakognosie - Phytopharmazie], Springer-Verlag, p. 1216, ISBN   978-3-540-34281-6 {{citation}}: Check |url= value (help)
  8. ↑ E. Tavcar, K. Stojilkovski, S. Kreft (2011), "Fagopyrin and its derivatives in buckwheat (Fagopyrum sp.)", Planta Medica, vol. 77, no. 12, pp. PL65, Bibcode:2011PlMed..7782714T, doi:10.1055/s-0031-1282714 {{citation}}: CS1 maint: multiple names: authors list (link)
  9. ↑ Ian W. Southon, John Buckingham (1989), [ , p. 430, at Google Books Dictionary of Alkaloids, Second Edition with CD-ROM], CRC Press, p. 430, ISBN   978-0-412-24910-5 {{citation}}: Check |url= value (help)
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