Record Information
Version 1.0
Update Date 1/22/2018 12:54:54 PM
Metabolite IDPAMDB000181
Name: Indole
Description:Indole is an aromatic heterocyclic organic compound. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing pyrrole ring. It can be produced by bacteria as a degradation product of the amino acid tryptophan. It occurs naturally in feces and has an intense fecal smell. At very low concentrations, however, it has a flowery smell, and is a constituent of many flower scents (such as orange blossoms) and perfumes. Natural jasmine oil, used in the perfume industry, contains around 2.5% of indole. Indole also occurs in CoAl tar. The participation of the nitrogen lone electron pair in the aromatic ring means that indole is not a base, and it does not behave like a simple amine.
  • 1-Azaindene
  • 1-Benzazole
  • 2,3-Benzopyrrole
  • Benzo[b]pyrrole
  • Indole
  • Ketole
Chemical Formula: C8H7N
Average Molecular Weight: 117.1479
Monoisotopic Molecular Weight: 117.057849229
CAS number: 120-72-9
IUPAC Name:1H-indole
Traditional IUPAC Name: indole
Chemical Taxonomy
Taxonomy DescriptionThis compound belongs to the class of organic compounds known as indoles. These are compounds containing an indole moiety, which consists of pyrrole ring fused to benzene to form 2,3-benzopyrrole.
Kingdom Organic compounds
Super ClassOrganoheterocyclic compounds
Class Indoles and derivatives
Sub ClassIndoles
Direct Parent Indoles
Alternative Parents
  • Indole
  • Benzenoid
  • Heteroaromatic compound
  • Pyrrole
  • Azacycle
  • Hydrocarbon derivative
  • Organonitrogen compound
  • Aromatic heteropolycyclic compound
Molecular Framework Aromatic heteropolycyclic compounds
External Descriptors
Physical Properties
State: Solid
Melting point: 52.5 °C
Experimental Properties:
Water Solubility:3.56 mg/mL [YALKOWSKY,SH & DANNENFELSER,RM (1992)]PhysProp
LogP:2.14 [HANSCH,C ET AL. (1995)]PhysProp
Predicted Properties
Water Solubility5.31 mg/mLALOGPS
pKa (Strongest Acidic)16.44ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count0ChemAxon
Hydrogen Donor Count1ChemAxon
Polar Surface Area15.79 Å2ChemAxon
Rotatable Bond Count0ChemAxon
Refractivity37.14 m3·mol-1ChemAxon
Polarizability12.82 Å3ChemAxon
Number of Rings2ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Biological Properties
Cellular Locations: Cytoplasm
Spectrum TypeDescriptionSplash Key
GC-MSGC-MS Spectrum - GC-MSNot Available
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 10V, Positive (Annotated)splash10-014i-0900000000-622dfed80152ea08d52aView in MoNA
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 25V, Positive (Annotated)splash10-0006-9100000000-2531cceca05522a5489eView in MoNA
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 40V, Positive (Annotated)splash10-014l-9000000000-5e07c15293929ff4440fView in MoNA
LC-MS/MSLC-MS/MS Spectrum - EI-B (MX-1303) , Positivesplash10-014i-6900000000-09af4d0af4e5f7259a59View in MoNA
LC-MS/MSLC-MS/MS Spectrum - EI-B (Unknown) , Positivesplash10-014i-9800000000-4160749bd673d5e00048View in MoNA
LC-MS/MSLC-MS/MS Spectrum - EI-B (HITACHI M-68) , Positivesplash10-014i-9800000000-33bf321019a6a8e3401aView in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF (UPLC Q-Tof Premier, Waters) , Positivesplash10-014i-0900000000-e6b11e225744a0d85f71View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, NegativeNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, NegativeNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, NegativeNot Available
MSMass Spectrum (Electron Ionization)splash10-014i-9700000000-3b1ec48b5bce79adb282View in MoNA
1D NMR1H NMR SpectrumNot Available
1D NMR1H NMR SpectrumNot Available
1D NMR13C NMR SpectrumNot Available
1D NMR1H NMR SpectrumNot Available
1D NMR13C NMR SpectrumNot Available
2D NMR[1H,1H] 2D NMR SpectrumNot Available
2D NMR[1H,13C] 2D NMR SpectrumNot Available
  • Agatsuma S, Sekino H, Watanabe H: Indoxyl-beta-D-glucuronide and 3-indoxyl sulfate in plasma of hemodialysis patients. Clin Nephrol. 1996 Apr;45(4):250-6. Pubmed: 8861801
  • Aoyama I, Miyazaki T, Niwa T: Preventive effects of an oral sorbent on nephropathy in rats. Miner Electrolyte Metab. 1999 Jul-Dec;25(4-6):365-72. Pubmed: 10681668
  • Citron DM, Baron EJ, Finegold SM, Goldstein EJ: Short prereduced anaerobically sterilized (PRAS) biochemical scheme for identification of clinical isolates of bile-resistant Bacteroides species. J Clin Microbiol. 1990 Oct;28(10):2220-3. Pubmed: 2229345
  • Cooke M, Leeves N, White C: Time profile of putrescine, cadaverine, indole and skatole in human saliva. Arch Oral Biol. 2003 Apr;48(4):323-7. Pubmed: 12663078
  • Coowar D, Bouissac J, Hanbali M, Paschaki M, Mohier E, Luu B: Effects of indole fatty alcohols on the differentiation of neural stem cell derived neurospheres. J Med Chem. 2004 Dec 2;47(25):6270-82. Pubmed: 15566297
  • Freedman DX, Belendiuk K, Belendiuk GW, Crayton JW: Blood tryptophan metabolism in chronic schizophrenics. Arch Gen Psychiatry. 1981 Jun;38(6):655-9. Pubmed: 7247628
  • Gambhir KK, McMenamy RH, Watson F: Positions in human serum albumin which involve the indole binding site. Sequence of 107-residue fragment. J Biol Chem. 1975 Sep 10;250(17):6711-9. Pubmed: 1158878
  • Kanehisa, M., Goto, S., Sato, Y., Furumichi, M., Tanabe, M. (2012). "KEGG for integration and interpretation of large-scale molecular data sets." Nucleic Acids Res 40:D109-D114. Pubmed: 22080510
  • Keseler, I. M., Collado-Vides, J., Santos-Zavaleta, A., Peralta-Gil, M., Gama-Castro, S., Muniz-Rascado, L., Bonavides-Martinez, C., Paley, S., Krummenacker, M., Altman, T., Kaipa, P., Spaulding, A., Pacheco, J., Latendresse, M., Fulcher, C., Sarker, M., Shearer, A. G., Mackie, A., Paulsen, I., Gunsalus, R. P., Karp, P. D. (2011). "EcoCyc: a comprehensive database of Escherichia coli biology." Nucleic Acids Res 39:D583-D590. Pubmed: 21097882
  • Kunka RL, Hussey EK, Shaw S, Warner P, Aubert B, Richard I, Fowler PA, Pakes GE: Safety, tolerability, and pharmacokinetics of sumatriptan suppositories following single and multiple doses in healthy volunteers. Cephalalgia. 1997 Jun;17(4):532-40. Pubmed: 9209775
  • Raw I, Schmidt BJ, Merzel J: Catecholamines and congenital pain insensitivity. Braz J Med Biol Res. 1984;17(3-4):271-9. Pubmed: 6085021
  • Scott AK: Sumatriptan clinical pharmacokinetics. Clin Pharmacokinet. 1994 Nov;27(5):337-44. Pubmed: 7851052
  • Takken W, van Loon JJ, Adam W: Inhibition of host-seeking response and olfactory responsiveness in Anopheles gambiae following blood feeding. J Insect Physiol. 2001 Mar;47(3):303-310. Pubmed: 11119776
  • van der Werf, M. J., Overkamp, K. M., Muilwijk, B., Coulier, L., Hankemeier, T. (2007). "Microbial metabolomics: toward a platform with full metabolome coverage." Anal Biochem 370:17-25. Pubmed: 17765195
  • Welch DF, Ahlin PA, Matsen JM: Differentiation of Haemophilus spp. in Respiratory isolate cultures by an indole spot test. J Clin Microbiol. 1982 Feb;15(2):216-9. Pubmed: 7040445
  • Winder, C. L., Dunn, W. B., Schuler, S., Broadhurst, D., Jarvis, R., Stephens, G. M., Goodacre, R. (2008). "Global metabolic profiling of Escherichia coli cultures: an evaluation of methods for quenching and extraction of intracellular metabolites." Anal Chem 80:2939-2948. Pubmed: 18331064
  • Yoshida M, Mishiro Y: [Indole production in human whole saliva] Shigaku. 1989 Aug;77(2):472-86. Pubmed: 2489307
Synthesis Reference: Grigoleit, Georg; Oberkobusch, Rudolf; Collin, Gerd. Indole from 2-ethylaniline. Ger. Offen. (1973), 6 pp.
Material Safety Data Sheet (MSDS) Download (PDF)
External Links:
Pubchem Compound ID798
Kegg IDC00463
ChemSpider ID776
Ligand ExpoIND


General function:
Involved in catalytic activity
Specific function:
The alpha subunit is responsible for the aldol cleavage of indoleglycerol phosphate to indole and glyceraldehyde 3- phosphate
Gene Name:
Locus Tag:
Molecular weight:
28.5 kDa
L-serine + 1-C-(indol-3-yl)glycerol 3-phosphate = L-tryptophan + glyceraldehyde 3-phosphate + H(2)O.
General function:
Involved in catalytic activity
Specific function:
The beta subunit is responsible for the synthesis of L- tryptophan from indole and L-serine
Gene Name:
Locus Tag:
Molecular weight:
43.7 kDa
L-serine + 1-C-(indol-3-yl)glycerol 3-phosphate = L-tryptophan + glyceraldehyde 3-phosphate + H(2)O.


General function:
Involved in amino acid transmembrane transporter activity
Specific function:
Involved in transporting tryptophan across the cytoplasmic membrane
Gene Name:
Locus Tag:
Molecular weight:
44.7 kDa