Plasma profiling of intact isoflavone metabolites by high-performance liquid chromatography and mass spectrometric identification of flavone glycosides daidzin and genistin in human plasma after administration of kinako.
The roles of isoflavones in the prevention of several hormone-dependent cancers and osteoporosis are of great interest. Despite many pharmacokinetics studies of the isoflavones, the actual types of conjugates circulating in the body and the position(s) of conjugation sites on the flavone skeleton are still uncertain because, in general, conjugated compounds in biological fluids have been evaluated by measuring the free aglycones obtained after selective enzymatic hydrolysis. Using an high-performance (HPLC)-UV-diode-array detector (DAD) method combined with solid-phase extraction, we have obtained HPLC profiles of isoflavone glycosides [daidzin (Din) and genistin (Gin)] and of intact isoflavone metabolites in human plasma: daidzein, genistein, daizein-7-glucuronide, daidzein-4'-glucuronide, genistein-7-glucuronide, genistein-4'-glucuronide, daidzein-7-sulfate, daidzein-4'-sulfate, genistein-7-sulfate, and genistein-4'-sulfate. We investigated the plasma profile of intact isoflavone metabolites in plasma obtained 1 to-7 h after orally administration of 50 g of kinako (baked soybean powder) to two healthy volunteers. The results of DAD analysis indicated that the main isoflavone metabolite peaks were identified on the HPLC chromatogram. Furthermore, the intact glycosides Din and Gin were detected in 1-h plasma samples by their positive electrospray ionization mass spectra, demonstrating that the glycosides Din and Gin can be absorbed from the gut.
Hosoda
Kaori
K
Kyorin University, School of Health Sciences, 476 Miyashita, Hachioji, Tokyo 192-0005, Japan.
Furuta
Takashi
T
Yokokawa
Akitomo
A
Ogura
Kenichiro
K
Hiratsuka
Akira
A
Ishii
Kazuo
K
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D019833:Genistein / Q000097:blood*; D006801:Humans; D007529:Isoflavones / Q000097:blood / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D012015:Reference Standards; D013025:Glycine max; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet
D007529:Isoflavones; C004742:daidzein; D019833:Genistein