ISSN:1096-620X    

DOI:10.1089/jmf.1999.2.85

年代:1999

数据来源: MAL

ISSN:1096-620X    

DOI:10.1089/jmf.1999.2.87

年代:1999

数据来源: MAL

摘要:

Phytoestrogens are natural products from plants that function as estrogen agonists. Here we briefly review the biochemistry, distribution, and proposed roles of phytoestrogens in plants. A primary role appears to be in host-microbe interactions. For example, results from our laboratory suggest that genistein plays multiple roles in soybean defense, including the initiation of hypersensitive (apoptotic) cell death and the activation or potentiation of the defense competency of soybean cells. Recent results from our laboratory suggest that mammalian estrogens and estrogen agonists (including other phytoestrogens and fungal estrogen agonists) and certain specific peroxisome proliferators can also potentiate defense competency in soybean. These findings suggest that some overlap in nuclear receptor or other lipid/steroid signaling pathways may exist between plants and animals.

ISSN:1096-620X    

DOI:10.1089/jmf.1999.2.93

年代:1999

数据来源: MAL

摘要:

Pharmacokinetic and metabolic studies of phytoestrogens of the isoflavone class have been hampered by the lack of suitable stable-isotope-labeled analogs. A method for preparation of a [13C]-labeled analog of daidzein is described. [2-13C]Daidzein was synthesized by reaction of [13C]diethoxydimethylaminomethane with 2,4-dihydroxybenzoin. The final product was purified to more than 99% by reverse-phase high-performance liquid chromatography and structural analysis confirmed by nuclear magnetic resonance spectroscopy and mass spectrometry. Because [2-13C]daidzein is analytically and metabolically stable, it is a suitable analog for use as an internal standard for quantifying daidzein in biological fluids using isotope dilution mass spectrometry. This nonradioactive tracer is also ideal for investigating the pharmacokinetics of daidzein in humans because it is biologically indistinguishable from the unlabeled form.

ISSN:1096-620X    

DOI:10.1089/jmf.1999.2.99

年代:1999

数据来源: MAL

摘要:

Stabile deuterated plant lignans D6-matairesinol, D8-secoisolariciresinol, and D8-anhydrosecoisolariciresinol are synthesized to be used as internal standards in isotope dilution technique of gas chromatography-mass spectrometry in the selected ion monitoring mode.

ISSN:1096-620X    

DOI:10.1089/jmf.1999.2.103

年代:1999

数据来源: MAL

ISSN:1096-620X    

DOI:10.1089/jmf.1999.2.107

年代:1999

数据来源: MAL

摘要:

High-performance liquid chromatography (HPLC) or capillary electrophoresis (CE) is particularly suited to the separation and analysis of a wide range of biological compounds. When investigating such compounds in complex matrices (e.g., blood, tissue, urine, foods), specificity of the detection method becomes an important issue. This can be overcome by extensive purification procedures before HPLC or CE analysis, but at the cost of a lot of effort and often unknown losses during the extraction and purification procedures. Such losses can be overcome by the addition of isotopically labeled internal standards, subject to their availability. The coupling of HPLC or CE with mass spectrometry provides a very specific method of detection. Compounds are transferred as ions to the gas phase by two types of spraying technologies, electrospray ionization (ESI) and heated nebulizer-atmospheric pressure chemical ionization. Although the mass-to-charge ratios of the molecular ions can be used to provisionally identify a compound, full confirmation of structure requires collision-induced dissociation and analysis of the resulting fragment ions. Combination of specific parent ion-daughter ion pairs allows for the quantitative measurement of isoflavones in the 1-5 pmol range with coefficients of variation for duplicate samples in the range of 5-9%. CE places greater demands on the mass spectrometer than does HPLC, because it generates narrow peak widths. A mass spectrometer with a scanning quadrupole analyzer does not enable full exploitation of the power of CE; in this context, an instrument with an ESI interface and a time-of-flight analyzer is ideal.

ISSN:1096-620X    

DOI:10.1089/jmf.1999.2.111

年代:1999

数据来源: MAL

摘要:

HPLC/PDA methodology was developed for phytoestrogen analysis in human blood, urine, and breast milk. Applications of this technique in four different observational studies showed that urinary excretion rates of isoflavonoids reflects soy consumption reliably. A case-control study in Shanghai showed a decrease in risk to develop breast cancer for women with high urinary isoflavone excretion. These findings support a potential breast cancer preventive effect achieved by soy consumption in populations that eat soy foods habitually.

ISSN:1096-620X    

DOI:10.1089/jmf.1999.2.119

年代:1999

数据来源: MAL

ISSN:1096-620X    

DOI:10.1089/jmf.1999.2.125

年代:1999

数据来源: MAL

摘要:

Highly sensitive plasma immunoassay methods based on time-resolved fluorometry were developed for plasma enterolactone, genistein, and daidzein. For daidzein and genistein three types of methods and for enterolactone two different methods were developed and validated and the results compared with our gas chromatographic-mass spectrometric reference method. All three compounds may be determined in duplicate in a 2-300 μ plasma sample, even in subjects with low phytoestrogen values

ISSN:1096-620X    

DOI:10.1089/jmf.1999.2.131

年代:1999

数据来源: MAL