Flavones

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Molecular structure of the flavone backbone with numbers

Flavones (flavus = yellow), are a class of flavonoids based on the backbone of 2-phenylchromen-4-one (2-phenyl-1-benzopyran-4-one) shown on the right.

Natural flavones include apigenin (4',5,7-trihydroxyflavone), luteolin (3',4',5,7-tetrahydroxyflavone), tangeritin (4',5,6,7,8-pentamethoxyflavone), chrysin (5,7-dihydroxyflavone), 6-hydroxyflavone, 7,8-dihydroxyflavone, baicalein (5,6,7-trihydroxyflavone), scutellarein (5,6,7,4'-tetrahydroxyflavone), and wogonin (5,7-dihydroxy-8-methoxyflavone). Synthetic flavones include diosmin and flavoxate.

Flavone also refers to the flavone compound 2-phenyl-4H-chromen-4-one.[1][2]

Intake and putative beneficial effects[edit]

Flavones are mainly found in cereals and herbs. In the West, the estimated daily intake of flavones is in the range 20–50 mg per day.[3] In recent years, scientific and public interest in flavones has grown, but there remains insufficient evidence that flavones have any effect in the human body. As interpreted by the Linus Pauling Institute, dietary flavones, and more generally polyphenols, have little or no direct antioxidant food value following digestion.[4] After ingestion, most flavones and polyphenols are rapidly metabolised and excreted.[5]

Drug interactions[edit]

Flavones have effects on CYP (P450) activity [6][7] which are enzymes that metabolize most drugs in the body.

Organic chemistry[edit]

In organic chemistry several methods exist for the synthesis of flavones:

Another method is the dehydrative cyclization of certain 1,3-diaryl diketones [8]

Flavone synthesis from 1,3-ketones

this particular study making use of an ionic liquid solvent and microwave irradiation.

Wessely–Moser rearrangement[edit]

The Wessely–Moser rearrangement (1930)[9] has been an important tool in structure elucidation of flavonoids. It involves the conversion of 5,7,8-trimethoxyflavone into 5,6,7-trihydroxyflavone on hydrolysis of the methoxy groups to phenol groups. It also has synthetic potential for example:[10]

Wessely–Moser rearrangement

This rearrangement reaction takes place in several steps: A ring opening to the diketone, B bond rotation with formation of a favorable acetylacetone-like phenyl-ketone interaction and C hydrolysis of two methoxy groups and ring closure.

Examples of flavones[edit]

Flavones and their structure [11]
Name Structure R3 R5 R6 R7 R8 R2' R3' R4' R5' R6'
Flavone backbone Flavon num.svg
Primuletin –OH
Chrysin –OH –OH
Tectochrysin –OH –OCH3
Primetin –OH –OH
Apigenin –OH –OH –OH
Acacetin –OH –OH –OCH3
Genkwanin –OH –OCH3 –OH
Echioidinin –OH –OCH3 –OH
Baicalein –OH –OH –OH
Oroxylon –OH –OCH3 –OH
Negletein –OH –OH –OCH3
Norwogonin –OH –OH –OH
Wogonin –OH –OH –OCH3
Geraldone –OH –OCH3 –OH
Tithonine –OCH3 –OH –OCH3
Luteolin –OH –OH –OH –OH
6-Hydroxyluteolin –OH –OH –OH –OH –OH
Chrysoeriol –OH –OH –OCH3 –OH
Diosmetin –OH –OH –OH –OCH3
Pilloin –OH –OCH3 –OH –OCH3
Velutin –OH –OCH3 –OCH3 –OH
Norartocarpetin –OH –OH –OH –OH
Artocarpetin –OH –OCH3 –OH –OH
Scutellarein –OH –OH –OH –OH
Hispidulin –OH –OCH3 –OH –OH
Sorbifolin –OH –OH –OCH3 –OH
Pectolinarigenin –OH –OCH3 –OH –OCH3
Cirsimaritin –OH –OCH3 –OCH3 –OH
Mikanin –OH –OCH3 –OCH3 –OCH3
Isoscutellarein –OH –OH –OH –OH
Zapotinin –OH –OCH3 –OCH3 –OCH3
Zapotin –OCH3 –OCH3 –OCH3 –OCH3
Cerrosillin –OCH3 –OCH3 –OCH3 –OCH3
Alnetin –OH –OCH3 –OCH3 –OCH3
Tricetin –OH –OH –OH –OH –OH
Tricin –OH –OH –OCH3 –OH –OCH3
Corymbosin –OH –OCH3 –OCH3 –OCH3 –OCH3
Nepetin –OH –OCH3 –OH –OH –OH
Pedalitin –OH –OH –OCH3 –OH –OH
Nodifloretin –OH –OH –OH –OCH3 –OH
Jaceosidin –OH –OCH3 –OH –OCH3 –OH
Cirsiliol –OH –OCH3 –OCH3 –OH –OH
Eupatilin –OH –OCH3 –OH –OCH3 –OCH3
Cirsilineol –OH –OCH3 –OCH3 –OCH3 –OH
Eupatorin –OH –OCH3 –OCH3 –OCH3 –OH
Sinensetin –OCH3 –OCH3 –OCH3 –OCH3 –OCH3
Hypolaetin –OH –OH –OH –OH –OH
Onopordin –OH –OH –OCH3 –OH –OH
Wightin –OH –OCH3 –OCH3 –OCH3 –OH
Nevadensin –OH –OCH3 –OH –OCH3 –OCH3
Xanthomicrol –OH –OCH3 –OCH3 –OCH3 –OH
Tangeretin –OCH3 –OCH3 –OCH3 –OCH3 –OCH3
Serpyllin –OH –OCH3 –OCH3 –OCH3 –OCH3 –OCH3
Sudachitin –OH –OCH3 –OH –OCH3 –OCH3 –OH
Acerosin –OH –OCH3 –OH –OCH3 –OH –OCH3
Hymenoxin –OH –OCH3 –OH –OCH3 –OCH3 –OCH3
Gardenin D –OH –OCH3 –OCH3 –OCH3 –OH –OCH3
Nobiletin –OCH3 –OCH3 –OCH3 –OCH3 –OCH3 –OCH3
Scaposin –OH –OCH3 –OH –OCH3 –OCH3 –OCH3 –OH
Name Structure R3 R5 R6 R7 R8 R2' R3' R4' R5' R6'

References[edit]

  1. ^ http://proj3.sinica.edu.tw/~chem/servxx6/files/paper_7744_1269418157.pdf
  2. ^ http://www.chemspider.com/Chemical-Structure.10230.html
  3. ^ Cermak R, Wolffram S (October 2006). "The potential of flavonoids to influence drug metabolism and pharmacokinetics by local gastrointestinal mechanisms". Curr. Drug Metab. 7 (7): 729–44. PMID 17073577. doi:10.2174/138920006778520570. 
  4. ^ Lotito, S; Frei, B (2006). "Consumption of flavonoid-rich foods and increased plasma antioxidant capacity in humans: Cause, consequence, or epiphenomenon?". Free Radical Biology and Medicine. 41 (12): 1727–46. PMID 17157175. doi:10.1016/j.freeradbiomed.2006.04.033. 
  5. ^ David Stauth (5 March 2007). "Studies force new view on biology of flavonoids". EurekAlert!; Adapted from a news release issued by Oregon State University. 
  6. ^ Cermak R, Wolffram S., The potential of flavonoids to influence drug metabolism and pharmacokinetics by local gastrointestinal mechanisms,Curr Drug Metab. 2006 Oct;7(7):729-44.
  7. ^ Si D, Wang Y, Zhou YH, et al. (March 2009). "Mechanism of CYP2C9 inhibition by flavones and flavonols". Drug Metab. Dispos. 37 (3): 629–34. PMID 19074529. doi:10.1124/dmd.108.023416. [1]
  8. ^ Sarda SR, Pathan MY, Paike VV, Pachmase PR, Jadhav WN, Pawar RP (2006). "A facile synthesis of flavones using recyclable ionic liquid under microwave irradiation" (PDF). Arkivoc. xvi: 43–8. doi:10.3998/ark.5550190.0007.g05. 
  9. ^ Wessely F, Moser GH (December 1930). "Synthese und Konstitution des Skutellareins". Monatsh. Chem. 56 (1): 97–105. doi:10.1007/BF02716040. 
  10. ^ Larget R, Lockhart B, Renard P, Largeron M (April 2000). "A convenient extension of the Wessely-Moser rearrangement for the synthesis of substituted alkylaminoflavones as neuroprotective agents in vitro". Bioorg. Med. Chem. Lett. 10 (8): 835–8. PMID 10782697. doi:10.1016/S0960-894X(00)00110-4. 
  11. ^ The Flavonoids - Springer. doi:10.1007/978-1-4899-2909-9. 

External links[edit]