Effect-directed analysis of endocrine-disrupting compounds in multi-contaminated sediment: identification of novel ligands of estrogen and pregnane X receptors

Anal Bioanal Chem. 2013 Mar;405(8):2553-66. doi: 10.1007/s00216-013-6708-5. Epub 2013 Jan 26.

Abstract

Effect-directed analysis (EDA)-based strategies have been increasingly used in order to identify the causative link between adverse (eco-)toxic effects and chemical contaminants. In this study, we report the development and use of an EDA approach to identify endocrine-disrupting chemicals (EDCs) in a multi-contaminated river sediment. The battery of in vitro reporter cell-based bioassays, measuring estrogenic, (anti)androgenic, dioxin-like, and pregnane X receptor (PXR)-like activities, revealed multi-contamination profiles. To isolate active compounds of a wide polarity range, we established a multi-step fractionation procedure combining: (1) a primary fractionation step using normal phase-based solid-phase extraction (SPE), validated with a mixture of 12 non-polar to polar standard EDCs; (2) a secondary fractionation using reversed-phase-based high-performance liquid chromatography (RP-HPLC) calibrated with 33 standard EDCs; and (3) a purification step using a recombinant estrogen receptor (ER) affinity column. In vitro SPE and HPLC profiles revealed that ER and PXR activities were mainly due to polar to mid-polar compounds, while dioxin-like and anti-androgenic activities were in the less polar fractions. The overall procedure allowed final isolation and identification of new environmental PXR (e.g., di-iso-octylphthalate) and ER (e.g., 2,4-di-tert-butylphenol and 2,6-di-tert-butyl-α-methoxy-p-cresol) ligands by using gas chromatography coupled with mass spectrometry with full-scan mode acquisition in mid-polar fractions. In vitro biological activity of these chemicals was further confirmed using commercial standards, with di-iso-octylphthalate identified for the first time as a potent hPXR environmental agonist.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, High Pressure Liquid / methods*
  • Endocrine Disruptors / chemistry*
  • Geologic Sediments / chemistry*
  • Kinetics
  • Ligands
  • Pregnane X Receptor
  • Receptors, Estrogen / agonists
  • Receptors, Estrogen / chemistry*
  • Receptors, Estrogen / genetics
  • Receptors, Estrogen / metabolism
  • Receptors, Steroid / agonists
  • Receptors, Steroid / chemistry*
  • Receptors, Steroid / genetics
  • Receptors, Steroid / metabolism
  • Solid Phase Extraction / methods*
  • Water Pollutants, Chemical / chemistry*

Substances

  • Endocrine Disruptors
  • Ligands
  • Pregnane X Receptor
  • Receptors, Estrogen
  • Receptors, Steroid
  • Water Pollutants, Chemical