CH-223191 Unit size Cat. code Docs Qty Price
2-methyl-2H-pyrazole-3-carboxylic acid; AhR Antagonist
10 mg

AhR Antagonist

CH-223191 is a synthetic antagonist for the cytosolic aryl hydrocarborn receptor (AhR) transcription factor [1].
It exerts a ligand-selective antagonism and appears to be more effective on halogenated aromatic hydrocarbons such as the xenobiotic 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), than on polycyclic aromatic hydrocarbons and non halogenated aromatic hydrocarbons such as FICZ and ITE, respectively [2].

InvivoGen's CH-223191 is of high quality, guaranteed free of bacterial contamination, and has been functionally tested on HepG2-Lucia™ AhR and HT29-Lucia™ AhR  reporter cells.


Read our review on AhR's key role in the intestinal microbiota and immunity.



1. Kim, S.H. et al., 2006. Novel compound 2-methyl-2H-pyrazole-3-carboxylic acid (2-methyl-4-o-tolylazo-phenyl)-amide (CH-223191) prevents 2,3,7,8-TCDD-Induced toxicity by antagonizing the aryl hydrocarbon receptor. Mol. Pharmacol. 69:1871-78.
2. Zhao B. et al., 2010. CH223191 is a ligand-selective antagonist of the Ah (Dioxin) receptor. Toxicol. Sci. 117:393-403.


Evaluation of cellular AhR inhibition by CH-223191
Evaluation of cellular AhR inhibition by CH-223191

Inhibition of AhR activity by CH-223191 in HepG2-Lucia™ Ahr cells.
The cells were stimulated with 30 nM TCDD or 30 μM ITE in the presence of 10 μM CH-223191. After overnight incubation, the AhR response was assessed by  determining Lucia  luciferase activity in the supernatant using.QUANTI-Luc™.
Percentages of the maximal response for the ligand with no inhibitor are shown.

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CAS number: 301326-22-7

Synonym: 2-methyl-2H-pyrazole-3-carboxylic acid

Solubility: 90 mM (30 mg/ml) in DMSO

Working concentration: 1µM (333 ng/ml) to 30 µM (10.1 μg/ml) for cell culture assays

Formula: C19H19N5O

Molecular weight: 333.4 g/mol

Quality control:

  • Purity ≥ 95% (UHPLC).
  • The absence of bacterial contamination (e.g. lipoproteins and endotoxins) has been confirmed using HEK-Blue™ TLR2 and HEK‑Blue™ TLR4 cells.
  • The inhibitory activity has been validated using cellular assays.
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  • 10 mg CH-223191

CH-223191 is shipped at room temperature.

Store at -20°C. 

Alert Protect this product from light.

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