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

Abstract

ABSTRACT:The roles of isoflavones in the prevention of several hormonedependent 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.

Metabolism and Disposition of Isoflavone Conjugated Metabolites in Humans after Ingestion of Kinako

“…Genistein [5,7-dihydroxy-3-(4-hydroxyphenyl)-4H-1-benzopyran-4-one, 4Ј,5,7-trihydroxyisoflavone] and luteolin-3Ј,7-di-O-glucoside were purchased from Extrasynthese (Genay, France). Daidzein-7-glucuronide (D-7-G), genistein-7-glucuronide (G-7-G), daidzein-4Ј,7-diglucuronide (D-4Ј,7-diG), and G-4Ј,7-diG were synthesized in our laboratory according to the method of Needs and Williamson (2001) (Hosoda et al, 2008(Hosoda et al, , 2010b. D-7G-4ЈS and G-7G-4ЈS were synthesized in our laboratory according to the method of Soidinsalo and Wähälä (2007) (Hosoda et al, 2010b).…”

“…D-7G-4ЈS and G-7G-4ЈS were synthesized in our laboratory according to the method of Soidinsalo and Wähälä (2007) (Hosoda et al, 2010b). Daidzein-4Ј-glucuronide (D-4Ј-G) and genistein-4Ј-glucuronide (G-4Ј-G) were isolated from human urine (Hosoda et al, 2008). Daidzein-7-sulfate (D-7-S), daidzein-4Ј-sulfate (D-4Ј-S), D-4Ј,7-diS, genistein-7-sulfate (G-7-S), genistein-4Ј-sulfate (G-4Ј-S), and genistein-4Ј,7-disulfate (G-4Ј,7-diS) were synthesized in our laboratory (Nakano et al, 2004).…”

Simultaneous determination of glucuronic acid and sulfuric acid conjugated metabolites of daidzein and genistein in human plasma by high-performance liquid chromatography

“…Genistein (5,7-dihydroxy-3-(4-hydroxyphenyl)-4H-1-benzopyran-4-one, 4 ,5,7-trihydroxyisoflavone) and luteolin-3 ,7-di-O-glucoside were purchased from Extrasynthese (Genay, France). Daidzein-7-glucuronide (D-7-G) and genistein-7-glucuronide (G-7-G) were synthesized according to the method of Needs and Williamson [35] in our laboratory [34]. Daidzein-4 -glucuronide (D-4 -G) and genistein-4 -glucuronide (G-4 -G) were isolated from human urine [34].…”

“…Daidzein-7-glucuronide (D-7-G) and genistein-7-glucuronide (G-7-G) were synthesized according to the method of Needs and Williamson [35] in our laboratory [34]. Daidzein-4 -glucuronide (D-4 -G) and genistein-4 -glucuronide (G-4 -G) were isolated from human urine [34]. Daidzein-7-sulfate (D-7-S), daidzein-4 -sulfate (D-4 -S), daidzein-4 ,7-disulfate (D-4 ,7-diS), genistein-7-sulfate (G-7-S), genistein-4 -sulfate (G-4 -S) and genistein-4 ,7-disulfate (G-4 ,7-diS) were synthesized in our laboratory [36].…”

“…We previously reported the HPLC chromatographic behaviors of the authentic standards of intact isoflavone metabolites, Dein, Gein, Dein-7-glucuronide (D-7-G), D-4 -G, Gein-7-glucuronides (G-7-G), G-4 -G, Dein-7-sufates (D-7-S), D-4 -S, Gein-7-sulfate (G-7-S) and G-4 -S by using HPLC-UV-diode-array detector (DAD) [34]. We also investigated the profile of these intact isoflavone metabolites in human plasma after intake of kinako.…”