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| Names | |
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| IUPAC name 4′,7-Dihydroxyisoflavone | |
| Systematic IUPAC name 7-Hydroxy-3-(4-hydroxyphenyl)-4H-1-benzopyran-4-one | |
| Other names 7-Hydroxy-3-(4-hydroxyphenyl)chromen-4-one Daidzeol Isoaurostatin | |
| Identifiers | |
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3D model (JSmol) | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
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| ECHA InfoCard | 100.006.942 |
| KEGG |
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| UNII | |
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| Properties | |
| C15H10O4 | |
| Molar mass | 254.23 g/mol |
| Appearance | Pale yellow prisms |
| Melting point | 315 to 323 °C (599 to 613 °F; 588 to 596 K) (decomposes) |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Daidzein (7-hydroxy-3-(4-hydroxyphenyl)-4H-chromen-4-one) is a naturally occurring compound found exclusively in soybeans and otherlegumes, and structurally belongs to a class of compounds known asisoflavones.[2] Daidzein and other isoflavones are produced in plants through thephenylpropanoid pathway of secondary metabolism and are used as signal carriers, and defense responses to pathogenic attacks.[3] Upon consumption of isoflavone-rich foods, daidzein has poorbioavailability and low watersolubility.[4]
Daidzein and other isoflavone compounds, such asgenistein, are present in a number ofplants andherbs like kwao krua (Pueraria mirifica) andkudzu. It can also be found inMaackia amurensis cell cultures.[5] Daidzein can be found in food such as maturesoybeans and soy products like soy protein concentrate,tofu andtextured vegetable protein.[2]
Total isoflavones in soybeans are—in general—37 percent daidzein, 57 percent genistein and 6 percentglycitein, according toUSDA data.[6] Soy germ contains 41.7 percent daidzein.[7]
Theisoflavonoid pathway has long been studied because of its prevalence in a wide variety of plant species, including as pigmentation in many flowers, as well as serving as signals in plants and microbes. The isoflavone synthase (IFS) enzyme was suggested to be a P-450 oxygenase family, and this was confirmed by Shinichi Ayabe's laboratory in 1999. IFS exists in two isoforms that can use bothliquiritigenin andnaringenin to give daidzein andgenistein respectively.[8]
Daidzein is an isoflavonoid derived from theshikimate pathway that forms an oxygen containing heterocycle through a cytochrome P-450-dependent enzyme that isNADPH dependent.[2]
The biosynthesis of daidzein begins with L-phenylalanine and undergoes a general phenylpropanoid pathway where the shikimate derived aromatic ring is shifted to the adjacent carbon of the heterocycle.[9] The process begins with phenylalanine ligase (PAL) cleaving the amino group from L-Phe forming the unsaturated carboxylic acid,cinnamic acid. Cinnamic acid is then hydroxylated by membrane protein cinnamate-4-hydroxylase (C4H) to formp-coumaric acid. P-coumaric acid then acts as the starter unit which gets loaded withcoenzyme A by 4-coumaroyl:CoA-ligase (4CL). The starter unit (A) then undergoes three iterations ofmalonyl-CoA resulting in (B), which enzymeschalcone synthase (CHS) and chalcone reductase (CHR) modify to obtain trihydroxychalcone. CHR is NADPH dependent.Chalcone isomerase (CHI) then isomerizes trihydroxychalcone toliquiritigenin, the precursor to daidzein.[8]
A radical mechanism has been proposed in order to obtain daidzein from liquiritigenin, where an iron-containing enzyme, as well as NADPH and oxygen cofactors are used by a 2-hydroxyisoflavone synthase to oxidize liquiritigenin to a radical intermediate (C). A 1,2 aryl migration follows to form (D), which is subsequently oxidized to (E). Lastly, dehydration of the hydroxy group on C2 occurs through a2-hydroxyisoflavanone dehydratase (specificallyGmHID1) to give daidzein.[9][3]
There is preliminary evidence that consuming soy foods rich in daidzein and isoflavones may improvecardiovascular function inpostmenopausal women[2] and lower the risk ofbreast cancer in premenopausal and postmenopausal women.[10]
Because daidzein is a defensive factor,Pseudomonas syringae produces theHopZ1b effector which degrades aGmHID1 product.[11]
{{cite journal}}: CS1 maint: multiple names: authors list (link)Isoflavones and theirglycosides | |
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| Isoflavones | |
| O-methylated isoflavones | |
| Glycosides | |
| Prenylated isoflavones | |
| Pyranoisoflavones | |
| Derivatives | |
| Synthetic | |
