Indirubin (2-(2-oxo-1H-indol-3-ylidene)-1H-indol-3-one) is a dietary-derived indole-based ligand of the cytosolic aryl hydrocarbon receptor (AhR) transcription factor [1].
Indirubin is an endogenous AhR agonist but its synthesis requires diet-derived tryptophan (Trp) amino. Indirubin results from Trp metabolism by the commensal gut microbiota and host hepatocytes [1]. Indirubin was shown to be more potent at activating human AhR than 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the prototypical AhR agonist [2]. Of note, indirubin is a more potent agonist of human AhR than murine AhR [3].
InvivoGen's indirubin is a high-quality product (>95% purity) and is guaranteed free of bacterial contamination. Each lot of indirubin is functionally tested in cellular assays using HepG2-Lucia™ AhR and HT29-Lucia™ AhR reporter cells.
Other AhR ligands, as well as an AhR antagonist, are also available.
References:
- Hubbard T.D. et al., 2015. Indole and tryptophan metabolism: endogenous and dietary routes to Ah receptor activation. Drug Metab. Dispos. 43:1522-35.
- Adachi J. et al., 2001. Indirubin and indigo are potent aryl hydrocarbon receptor ligands present in human urine. J. Biol. Chem. 276:31475-78.
- Flaveny C.A. et al., 2009. Ligand selectivity and gene regulation by the human aryl hydrocarbon receptor in transgenic mice. Mol. Pharmacol. 75:1412-20.