4234-02-0Relevant articles and documents
Development of a simple method for the determination of genistein, daidzein, biochanin A, and formononetin (Biochanin B) in human urine
Tekel, Jozef,Daeseleire, Els,Heeremans, An,Van Peteghem, Carlos
, p. 3489 - 3494 (1999)
A simple method was developed for the determination of free and/or total isoflavones daidzein, genistein, and their respective 4'-methoxy derivatives biochanin A and formononetin (biochanin B) at low levels in human urine. A solid-phase extraction on octadecyl silica (C18) columns was used for the isolation of the phytoestrogens from the matrix. An extraction on a ChemElut 1010 column connected on-line to a Florisil cartridge by a Teflon stopcock was used for effective eluate purification. A mixture of dichloromethane and ethyl acetate was used for elution of the isoflavones from the columns in tandem. The isoflavones were determined as trimethylsilyl (TMS) ethers using GC/MSSIM after separation on an HP-5MS fused silica column. TMS ethers were obtained by using BSTFA containing 1% of TMCS. For the determination of free isoflavones 6-hydroxyflavone was used as internal standard, whereas robigenin was used in the case of total isoflavone determination. Recoveries for free isoflavones under study varied from 63.5 to 89.6% at the 25 ng mL-1 level and from 63.5 to 89.2% at the 5 ng mL-1 level in urine. Analytical curves were linear between 5 and 25 ng mL-1. Detection limits varied from 1 ng mL-1 for formononetin to 2.3 ng mL-1 for daidzein. Recoveries for total isoflavone determination after enzymatic hydrolysis with glucuronidase from Helix pomatia ranged from 56.5 to 77.1% at the 25 ng mL-1 level.
Syntheses of Isoflavones and Isoflavone Glycosides, and Their Inhibitory Activity against Bovine Liver &β-Galactosidase
Nishiyama, Kiyotoshi,Esaki, Sachiko,Deguchi, Ikuko,Sugiyama, Naoko,Kamiya, Shintaro
, p. 107 - 114 (2007/10/02)
To clarify the relationship between the structure and inhibitory action toward β-D-galactosidase (EC 3.2.1.21) of isoflavones and isoflavone glycosides, a number of polyhydroxyisoflavones, and the α-L-rhamnosides and β-L-quinovosides of daidzein and genistein were synthesized.Among the polyhydroxyisoflavones, 2',3',4',7-tetrahydroxyisoflavone showed the strongest inhibitory activity (Ki = 26 * 10-6 M).Among the glycosides, all the L-rhamnosides were strong inhibitors, of which genistein 4',7-di-O-α-L-rhamnoside was the strongest (Ki = 4.44 * 10-6 M), while all the isoflavone β-L-quinovosides were considerably weak or possessed no inhibition.
