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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2000-9-12
pubmed:abstractText
Genistein is the principal soy isoflavone to which the putative beneficial effects of soy consumption have been attributed; however, the possibility of adverse biological effects (e.g., estrogenic, antithyroid) has also been raised. This paper describes development and validation of a simple and sensitive analytical method for the determination of genistein in the blood of rats receiving dietary genistein (<0.5-1250 microg of genistein aglycone/g of chow). The method uses serum/plasma deproteination, liquid-liquid extraction, deuterated genistein and daidzein internal standards, isocratic LC separation, and electrospray mass spectrometric quantification using selected ion monitoring. Extraction efficiency is approximately 85%, the detection limits for genistein and daidzein from 50 microL of rat blood are approximately 5 nM, and the limit of quantification is approximately 15 nM. Interassay precision (relative standard deviation 4.5-4.6%) and intraassay precision (3.3-6.7%) were determined from replicate analysis of a spiked control and an incurred serum sample. The distribution of conjugated and unconjugated forms of genistein in the blood of rats was determined using selective enzyme hydrolysis. The glucuronide was the predominant metabolite (>90%), and only small amounts of the sulfate conjugate and the aglycone were observed at all dose levels. No evidence for additional metabolites was obtained. The 7- and 4'-glucuronide conjugates of genistein were identified using electrospray mass spectrometry and (1)H NMR. Total blood genistein ranged from <15 nM in animals fed soy-free control diet to as high as 8.9 microM in male rats fed 1250 microg of genistein/g of chow and encompasses blood isoflavone levels observed in humans consuming a typical Asian diet and nutritional supplements (0.1-1 microM) and infants consuming soy formulas (2-7 microM).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-8561
pubmed:author
pubmed:issnType
Print
pubmed:volume
47
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3764-70
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Quantification of soy isoflavones, genistein and daidzein, and conjugates in rat blood using LC/ES-MS.
pubmed:affiliation
National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas 72079, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.