Characterization and Biological Potency of Mono- to Tetra-Halogenated Carbazoles

Nicole Riddell, Un Ho Jin, Stephen Safe, Yating Cheng, Brock Chittim, Alex Konstantinov, Robert Parette, Miren Pena-Abaurrea, Eric J. Reiner, David Poirier, Tomislav Stefanac, Alan J. McAlees, Robert McCrindle

Research output: Contribution to journalArticlepeer-review

57 Scopus citations


This paper deals with the characterization and aryl hydrocarbon receptor (AhR) agonist activities of a series of chlorinated, brominated, and mixed bromo/chlorocarbazoles, some of which have been identified in various environmental samples. Attention is directed here to the possibility that halogenated carbazoles may currently be emitted into the environment as a result of the production of carbazole-containing polymers present in a wide variety of electronic devices. We have found that any carbazole that is not substituted in the 1,3,6,8 positions may be lost during cleanup of environmental extracts if a multilayer column is utilized, as is common practice for polychlorinated dibenzo-p-dioxin (dioxin) and related compounds. In the present study, 1H NMR spectral shift data for 11 relevant halogenated carbazoles are reported, along with their gas chromatographic separation and analysis by mass spectrometry. These characterization data allow for confident structural assignments and the derivation of possible correlations between structure and toxicity based on the halogenation patterns of the isomers investigated. Some halogenated carbazoles exhibit characteristics of persistent organic pollutants and their potential dioxin-like activity was further investigated. The structure-dependent induction of CYP1A1 and CYP1B1 gene expression in Ah-responsive MDA-MB-468 breast cancer cells by these carbazoles was similar to that observed for other dioxin-like compounds, and the magnitude of the fold induction responses for the most active halogenated carbazoles was similar to that observed for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). 2,3,6,7-Tetrachlorocarbazole was one of the most active halogenated carbazoles and, like TCDD, contains 4 lateral substituents; however, the estimated relative effect potency for this compound (compared to TCDD) was 0.0001 and 0.0032, based on induction of CYP1A1 and CYP1B1 mRNA, respectively. (Graph Presented).

Original languageEnglish (US)
Pages (from-to)10658-10666
Number of pages9
JournalEnvironmental Science and Technology
Issue number17
StatePublished - Sep 1 2015

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry


Dive into the research topics of 'Characterization and Biological Potency of Mono- to Tetra-Halogenated Carbazoles'. Together they form a unique fingerprint.

Cite this