title: Quantitative determination of acetyl glucoside isoflavones and their metabolites in human urine using combined liquid chromatography-mass spectrometry.
abstract: To investigate whether the bioavailability of isoflavones could be an alternative to fermented soy foods, the conjugated forms of soy nutritional supplement (containing 98% acetyl glucoside isoflavones) were consumed by eight human volunteers (three were Asian people and five were British). Their daily urine samples were collected before and after a 5-week consumption of supplementation period. Conjugated isoflavones of genistein, daidzein and glycitein were hydrolyzed by enzyme, extracted with methyl tert-butyl ether and analysed using liquid chromatography coupled with electrospray tandem mass spectrometry. Daidzein, genistein, glycitein, dihydrogenistein, dihydrodaidzein and O-desmethylangolensin were identified and quantified simultaneously with high recoveries. The levels of free isoflavones and total isoflavones were compared, and isoflavone glucuronides were identified much higher than the corresponding sulfates or aglycone isoflavones. This method provided the measurement of isoflavones with high sensitivity and specificity and simplified the sample pre-treatment procedure. The limitation of detections of dihydrodaidzein, 3'-hydroxydaidzein, glycitein, daidzein, genistein, dihydrogenistein and O-desmethylangolensin were 37, 23.5, 12.2, 15.4, 14.8, 2.20 and 0.31 pmol, respectively. Only 0.5 ml of urine sample was needed.
authors.affiliation: State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Gaopeng Street, Keyuan Road 4, Chengdu 610041, China. lijuan17@hotmail.com
authors.forename: Lijuan
authors.initials: L
authors.lastname: Chen
authors.forename: Xia
authors.initials: X
authors.lastname: Zhao
authors.forename: Linyu
authors.initials: L
authors.lastname: Fang
authors.forename: David E
authors.initials: DE
authors.lastname: Games
mesh_terms: D000328:Adult; D044466:Asian People; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004032:Diet; D005260:Female; D005960:Glucosides / Q000652:urine*; D006801:Humans; D007529:Isoflavones / Q000652:urine*; D013058:Mass Spectrometry / Q000379:methods*; D008875:Middle Aged; D030262:Soybean Proteins / Q000008:administration & dosage; D044465:White People
chemical_list: D005960:Glucosides; D007529:Isoflavones; D030262:Soybean Proteins