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

25 Citations (Scopus)

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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