Orally administered isoflavones are present as glucuronides in the human prostate

Laurent Guy, Nicolas Vedrine, Mireia Urpi-Sarda, Angel Gil-Izquierdo, Nawaf Al-Maharik, Jean-Paul Boiteux, Augustin Scalbert, Christian Remesy, Nigel P. Botting, Claudine Manach

Research output: Contribution to journalArticlepeer-review

Abstract

Better knowledge of the bioavailability and metabolism of isoflavones in prostate tissue is needed to further investigate their mechanisms of action in the context of prostate cancer prevention. A total of 12 men with benign prostatic hyperplasia received soy extract supplementation (3 Evestrel (R) capsules, providing a total of 112.5 mg isoflavones aglycone eq/day) for 3 days before prostate surgery. Blood and prostate tissues were sampled and metabolites were identified using electrospray ionization liquid chromatography tandem mass spectrometry (LC-ESI-MS/MS) and chemically synthesized standards of glucuronidated isoflavones. The main metabolites were the same in prostate tissue and in plasma, namely, 2 monoglucuronides of daidzein and 2 monoglucuronides; of genistein. Concentrations of total isoflavones; measured in prostate reached 1.05 +/- 0.62 nmol/g tissue (range 0.30-2.23) at the time of sampling, 12 h after the last isoflavone supplementation. At that time point, prostate concentrations were lower than plasma concentrations in all volunteers: 0.47 nmoL/g vs. 0.66 mu M for daidzein and 0.58 Nmol/g vs. 0.78 mu M for genistein. Isoflavone mechanisms of action should thus be investigated in in vitro cell studies using physiological conditions, intracellular concentrations below 5 nmol/g and no intracellular deconjugation of the monoglucuronide metabolites.

Original languageEnglish
Pages (from-to)461-468
Number of pages8
JournalNutrition and Cancer
Volume60
DOIs
Publication statusPublished - Jul 2008

Keywords

  • PURIFIED SOY ISOFLAVONES
  • PHYTO-ESTROGENS
  • CANCER RISK
  • IN-VITRO
  • MEN
  • GENISTEIN
  • PLASMA
  • METABOLITES
  • IMMIGRANTS
  • DAIDZEIN

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