Coumestrol

KULLING s E, ROSENBERG B, JACOBS E, METZLER M (1999) The phytoestrogens coumestrol and genistein induce structural and chromosomal aberrations in cultured human peripheral blood lympocytes. Arch Toxicol. Ti 50-54. 

PATISAUL H B, WHITTEN p L, YOUNG L J (1999) Regulation of oestrogen receptor beta mRNA in the brain opposite effects of 17beta-oestradiol and the phytoestrogen, coumestrol. Brain Res Mol Brain Res. 67 165-71. 

MAZUR W, FOTSIS T, WAHALA K, OJALA S, SALAKKA A and ADLERCREUTZ H (1996) Isotope dilution gas chromatographic-mass spectrometric method for the determination of isoflavonoids, coumestrol and lignans in food samples. Biochem. 233 (2) 169-80. 

WHITTEN P L, PATISAUL H B and YOUNG L J (2002) NeuTobehavioral actions of coumestrol and related isoflavonoids in rodents. Neurotoxicol Teratol. 24 (1) 47-54. 

The basic structures of flavanones, flavones, and isoflavones together with coumestrol, an intermediate in the phenylpropane metabolism, are given in Fig. 2. The 3,5,7,3 -tetrahydroxy-4 -methoxyflavanone is a nod gene inducer in Rhizo-bium leguminosarum bv. viciae the 3, 4, 5,7-tetrahydroxyflavone, in Rhizobium ineliloti and 4,7-dihydroxyisoflavone, in Bradyrhizobium japonicum. Coumestrol, an intermediate in phenylpropane metabolism, is only a weak inducer (7). 

A detailed analysis of the root exudate of Phaseolus vulgaris found six flavonoids daidzein, coumestrol, naringenin, genistein, liquiritigenin, and isoli-... 

Coumestrol has been prepared via a photocyclization of the glyoxylate ester shown below through consecutive 5-hydrogen abstraction and cyclization processes, and is followed by... 

The phytoestrogens (isoflavones) contain a flavone nucleus. Examples of isoflavones are genistein, formononetin and coumestrol, all with potent estrogenic activity. Soybean isoflavones are a concern in human nutrition because of their estrogenic benefits. 

In 1987, Ken Setchell first described the method for the isolation of phytoestrogen in soy (Setchell et al., 1987). The phytoestrogens daidzein, genistein, coumestrol, formononetin, and biochanin-A were separated on a Cl8 reversed-phase column (Hypersil ODS) with methanol-0.1 M ammonium acetate buffer, pH 4.6 (60 40 v/v), as eluent. The retention and resolution were affected by buffer concentrations, pH type, and proportion of organic solvent in the mobile phase. Detection in the low picograms range was achieved with an electrochemical detector, and the compounds were positively identified by HPLC-thermospray mass spectrometry. 

In Australia, lambing in sheep has dropped to as little as 30% after grazing on subterranean clover. Trifolium subterraneum. The clover contains the isoflavonoids formononetin and genistein (Fig. 11.11). These compounds mimic the steroidal nucleus of the natural female hormone estrone. Alfalfa, M. sativa, and ladino clover. Trifolium repens, contain the even more potent isoflavonoid coumestrol. It is 30 times more active than genistein or formononetin, but occurs in lower concentrations in the plant (Shutt, 1976). 

Genistein genistein-7-O-glycoside eriodictyol naringenin daidzein coumestrol liquiritigenin isoliquiritigenin... 

Glycine max Coumestrol, phaseollin, afrormosin Soybean looper (Pseudoplusia 375,... 

In complex heterocyclic compounds, the terms coumarano, couma-rono, coumarino are therefore rejected, although they allow a shortening of the occasionally somewhat cumbersome and forbidding Chemical Abstracts nomenclature thus, coumestrol (4) will not be called the dihydroxy derivative of coumarono[3,2-c]coumarin,7 but 3,9-dihydroxy-6 -benzofuro[3,2-c][ l]benzopyran-6-one. 

Simpler names for compounds of type 4 (mentioned in the guiding index of Chemical Abstracts) will be used in this survey the fundamental heterocycle 6f/-benzofuro[3,2-c][l]benzopyran-6-one is called cou-mestan.8 Coumestrol (4) becomes 3,9-dihydroxycoumestan. Another derivative of the same family, waedelolactone,9 is 3-methoxy-l,8,9-trihydroxycoumestan. In this connection, it would be advisable, for natural compounds of botanical origin, to put the corresponding chemical name in brackets. 

Coumestans,21 although they have a fused benzofuran ring, will be surveyed as being 8-lactones of 2-(2-hydroxyphenyl)-3-benzofuran carboxylic acids [coumestrol (4)22 is the 8-lactone of 2-(2,4-dihydroxy-phenyl)-6-hydroxy-3-benzofurancarboxylic acid]. The synthesis of some rotenoids 23 from benzofuran derivatives will also be reviewed, but dibenzofuran derivatives, such as usnic acid and its derivatives, will not be treated. 

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