Determination of rat oral bioavailability of soy-derived phytoestrogens using an automated on-column extraction procedure and electrospray tandem mass spectrometry

J Chromatogr B Analyt Technol Biomed Life Sci. 2003 Oct 25;796(1):71-86. doi: 10.1016/j.jchromb.2003.08.003.


In recent years, consumption of herbal supplements as an alternative to pharmaceutical drug therapy has increased. For example, with the health claims labeling which describes the link between soy-protein and a reduced risk of coronary heart disease (CHD), the consumption of soy and soy-derived phytoestrogens has increased dramatically. That being said, the oral bioavailability of only a few soy phytoestrogens such as Daidzein and Genestein have been previously estimated. In this paper, we present the calculated percent of rat oral bioavailability of five soy-derived phytoestrogens (Genistein, Daidzein, Biochanin A, Coumestrol, and Zearalenone) in male Sprague-Dawley rats. The plasma quantitation required for the bioavailability calculation is performed by using a rapid on-line plasma extraction procedure for the quantitative analysis. To further speed up the analysis the rats were dosed using the 'n-in-one' (cassette) protocol. The rapid on-line extraction/quantitation methodology coupled to the cassette dosing analysis of phytoestrogens is the key point of this paper. The limit of quantitation (LOQ) for each compound was 1-1000 ng/ml with each plasma sample analysis taking less than 2 min. In general the percent oral bioavailability was determined to be between 11 and 28%.

MeSH terms

  • Administration, Oral
  • Animals
  • Automation
  • Biological Availability
  • Isoflavones / administration & dosage
  • Isoflavones / blood
  • Isoflavones / chemistry
  • Isoflavones / pharmacokinetics*
  • Male
  • Phytoestrogens
  • Plant Preparations / administration & dosage
  • Plant Preparations / blood
  • Plant Preparations / chemistry
  • Plant Preparations / pharmacokinetics*
  • Rats
  • Rats, Sprague-Dawley
  • Sensitivity and Specificity
  • Soybeans / chemistry*
  • Spectrometry, Mass, Electrospray Ionization / methods*


  • Isoflavones
  • Phytoestrogens
  • Plant Preparations