List of endogenous AHR activators derived from indole or tryptophan metabolism

OriginCompoundStructureMWConfirmed LigandHuman AHR Selective AgonistMouse AHR Selective AgonistReferences
Exogenous2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)Embedded Image321.97Poland and Knutson, 1982
Dietarylndole-3-carbinol (I3C)Embedded Image147.18Bjeldanes et al., 1991; Ito et al., 2007
Dietarylndole-3-acetonitrile (I3ACN)Embedded Image156.18Bjeldanes et al., 1991
Dietary3,3′-Diindolylmethane (DIM)Embedded Image246.31Bjeldanes et al., 1991
Dietary2-(Indol-3-ylmethyl)-3,3′-diindolylmethane (Ltr-1)Embedded Image369.47Bjeldanes et al., 1991
DietaryIndolo[3,2-b]carbazole (ICZ)Embedded Image254.28Bjeldanes et al., 1991; Jellinck et al., 1993
Dietary2-(1′H-indole-3′-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE)Embedded Image286.31Song et al., 2002
MicrobialIndoleEmbedded Image117.15Miller, 1997; Hubbard, 2015
Microbiallndole-3-acetic acid (IAA)Embedded Image175.18Miller, 1997; Jin et al., 2014
Microbiallndole-3-aldehyde (IAld)Embedded Image145.16Bjeldanes et al., 1991; Zelante et al., 2013
MicrobialTryptamineEmbedded Image160.22Miller, 1997; Jin et al., 2014
Microbial3-Methyl-indole (skatole)Embedded Image131.17*Weems and Yost, 2010; Hubbard, 2015
YeastTryptamineEmbedded Image248.24*Schrenk et al., 1999; Vlachos et al., 2012
Microbial/host metabolismIndigoEmbedded Image248.24Adachi et al., 2001; Peter Guengerich et al., 2004; Sugihara et al., 2004
Microbial/host metabolismIndirubinEmbedded Image262.27Adachi et al., 2001; Peter Guengerich et al., 2004; Sugihara et al., 2004; Flaveny et al., 2009
Microbial/host metabolismlndoxyl-3-sulfate (I3S)Embedded Image213.21Schroeder et al., 2010
Host metabolismKynurenine (Kyn)Embedded Image208.21Mezrich et al., 2010; Opitz et al., 2011
Host metabolismKynurenic acid (KA)Embedded Image189.17DiNatale et al., 2010a
Host metabolismXanthurenic acidEmbedded Image205.17*DiNatale et al., 2010a
Host metabolismCinnabarinic acid (CA)Embedded Image300.22*Lowe et al., 2014
UV-light oxidation6-Formylindolo[3,2-b]carbazole (FICZ)Embedded Image284.31Rannug et al., 1987, 1995
  • MW, molecular weight.

  • * Molecule is an activator of AHR, but further ligand binding assays are required.