Indole (English Wikipedia)

International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. p. 213. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4.
Oswald, Iain W. H.; Paryani, Twinkle R.; Sosa, Manuel E.; Ojeda, Marcos A.; Altenbernd, Mark R.; Grandy, Jonathan J.; Shafer, Nathan S.; Ngo, Kim; Peat, Jack R.; Melshenker, Bradley G.; Skelly, Ian; Koby, Kevin A.; Page, Michael F. Z.; Martin, Thomas J. (2023-10-12). "Minor, Nonterpenoid Volatile Compounds Drive the Aroma Differences of Exotic Cannabis". ACS Omega. 8 (42): 39203–39216. doi:10.1021/acsomega.3c04496. ISSN 2470-1343. PMC 10601067. PMID 37901519.
Liu, Yuping; Miao, Zhiwei; Guan, Wei; Sun, Baoguo (26 March 2012). "Analysis of Organic Volatile Flavor Compounds in Fermented Stinky Tofu Using SPME with Different Fiber Coatings". Molecules. 17 (4): 3708–3722. doi:10.3390/molecules17043708. PMC 6268145. PMID 22450681.
Lee, Jung Goo (21 October 2019). "The Neuroprotective Effects of Melatonin: Possible Role in the Pathophysiology of Neuropsychiatric Disease". Brain Sciences. 9 (285): 285. doi:10.3390/brainsci9100285. PMC 6826722. PMID 31640239.
Baeyer, A. (1866). "Ueber die Reduction aromatischer Verbindungen mittelst Zinkstaub" [On the reduction of aromatic compounds by means of zinc dust]. Annalen der Chemie und Pharmacie. 140 (3): 295–296. doi:10.1002/jlac.18661400306.
Baeyer, A.; Emmerling, A. (1869). "Synthese des Indols" [Synthesis of indole]. Berichte der Deutschen Chemischen Gesellschaft. 2: 679–682. doi:10.1002/cber.186900201268.
Van Order, R. B.; Lindwall, H. G. (1942). "Indole". Chem. Rev. 30: 69–96. doi:10.1021/cr60095a004.
Lee, Jin-Hyung; Lee, Jintae (2010). "Indole as an intercellular signal in microbial communities". FEMS Microbiology Reviews. 34 (4): 426–44. doi:10.1111/j.1574-6976.2009.00204.x. ISSN 0168-6445. PMID 20070374.
Zhang LS, Davies SS (April 2016). "Microbial metabolism of dietary components to bioactive metabolites: opportunities for new therapeutic interventions". Genome Med. 8 (1): 46. doi:10.1186/s13073-016-0296-x. PMC 4840492. PMID 27102537. Lactobacillus spp. convert tryptophan to indole-3-aldehyde (I3A) through unidentified enzymes [125]. Clostridium sporogenes convert tryptophan to IPA [6], likely via a tryptophan deaminase. ... IPA also potently scavenges hydroxyl radicals
Table 2: Microbial metabolites: their synthesis, mechanisms of action, and effects on health and disease
Figure 1: Molecular mechanisms of action of indole and its metabolites on host physiology and disease
Wikoff WR, Anfora AT, Liu J, Schultz PG, Lesley SA, Peters EC, Siuzdak G (March 2009). "Metabolomics analysis reveals large effects of gut microflora on mammalian blood metabolites". Proc. Natl. Acad. Sci. U.S.A. 106 (10): 3698–3703. Bibcode:2009PNAS..106.3698W. doi:10.1073/pnas.0812874106. PMC 2656143. PMID 19234110. Production of IPA was shown to be completely dependent on the presence of gut microflora and could be established by colonization with the bacterium Clostridium sporogenes.
IPA metabolism diagram
Chyan YJ, Poeggeler B, Omar RA, Chain DG, Frangione B, Ghiso J, Pappolla MA (July 1999). "Potent neuroprotective properties against the Alzheimer beta-amyloid by an endogenous melatonin-related indole structure, indole-3-propionic acid". J. Biol. Chem. 274 (31): 21937–21942. doi:10.1074/jbc.274.31.21937. PMID 10419516. S2CID 6630247. [Indole-3-propionic acid (IPA)] has previously been identified in the plasma and cerebrospinal fluid of humans, but its functions are not known. ... In kinetic competition experiments using free radical-trapping agents, the capacity of IPA to scavenge hydroxyl radicals exceeded that of melatonin, an indoleamine considered to be the most potent naturally occurring scavenger of free radicals. In contrast with other antioxidants, IPA was not converted to reactive intermediates with pro-oxidant activity.
Ehmann, Axel (1977-02-11). "The van URK-Salkowski reagent — a sensitive and specific chromogenic reagent for silica gel thin-layer chromatographic detection and identification of indole derivatives". Journal of Chromatography A. 132 (2): 267–276. doi:10.1016/S0021-9673(00)89300-0. ISSN 0021-9673. PMID 188858.
Darkoh, Charles; Chappell, Cynthia; Gonzales, Christopher; Okhuysen, Pablo (December 2015). Schloss, P. D. (ed.). "A Rapid and Specific Method for the Detection of Indole in Complex Biological Samples". Applied and Environmental Microbiology. 81 (23): 8093–8097. Bibcode:2015ApEnM..81.8093D. doi:10.1128/AEM.02787-15. ISSN 0099-2240. PMC 4651089. PMID 26386049.
Gilbert, Sarah; Xu, Jenny; Acosta, Kenneth; Poulev, Alexander; Lebeis, Sarah; Lam, Eric (2018). "Bacterial Production of Indole Related Compounds Reveals Their Role in Association Between Duckweeds and Endophytes". Frontiers in Chemistry. 6: 265. Bibcode:2018FrCh....6..265G. doi:10.3389/fchem.2018.00265. ISSN 2296-2646. PMC 6052042. PMID 30050896.
Matulis, Paulius; Kutraite, Ingrida; Augustiniene, Ernesta; Valanciene, Egle; Jonuskiene, Ilona; Malys, Naglis (January 2022). "Development and Characterization of Indole-Responsive Whole-Cell Biosensor Based on the Inducible Gene Expression System from Pseudomonas putida KT2440". International Journal of Molecular Sciences. 23 (9): 4649. doi:10.3390/ijms23094649. ISSN 1422-0067. PMC 9105386. PMID 35563040.
Ramesh, Deepthi; Joji, Annu; Vijayakumar, Balaji Gowrivel; Sethumadhavan, Aiswarya; Mani, Maheswaran; Kannan, Tharanikkarasu (15 July 2020). "Indole chalcones: Design, synthesis, in vitro and in silico evaluation against Mycobacterium tuberculosis". European Journal of Medicinal Chemistry. 198 112358. doi:10.1016/j.ejmech.2020.112358. ISSN 0223-5234. PMID 32361610. S2CID 218490655.
Qin, Hua-Li; Liu, Jing; Fang, Wan-Yin; Ravindar, L.; Rakesh, K. P. (15 May 2020). "Indole-based derivatives as potential antibacterial activity against methicillin-resistance Staphylococcus aureus (MRSA)". European Journal of Medicinal Chemistry. 194 112245. doi:10.1016/j.ejmech.2020.112245. ISSN 0223-5234. PMID 32220687. S2CID 214695328.
Thanikachalam, Punniyakoti Veeraveedu; Maurya, Rahul Kumar; Garg, Vishali; Monga, Vikramdeep (15 October 2019). "An insight into the medicinal perspective of synthetic analogs of indole: A review". European Journal of Medicinal Chemistry. 180: 562–612. doi:10.1016/j.ejmech.2019.07.019. ISSN 0223-5234. PMID 31344615. S2CID 198911553.
Kumari, Archana; Singh, Rajesh K. (1 August 2019). "Medicinal chemistry of indole derivatives: Current to future therapeutic prospectives". Bioorganic Chemistry. 89 103021. doi:10.1016/j.bioorg.2019.103021. ISSN 0045-2068. PMID 31176854. S2CID 182950054.
Jia, Yanshu; Wen, Xiaoyue; Gong, Yufeng; Wang, Xuefeng (15 August 2020). "Current scenario of indole derivatives with potential anti-drug-resistant cancer activity". European Journal of Medicinal Chemistry. 200 112359. doi:10.1016/j.ejmech.2020.112359. ISSN 0223-5234. PMID 32531682. S2CID 219021072.
Gribble, G. W. (2000). "Recent developments in indole ring synthesis—methodology and applications". J. Chem. Soc. Perkin Trans. 1 (7): 1045. doi:10.1039/a909834h.
Cacchi, S.; Fabrizi, G. (2005). "Synthesis and Functionalization of Indoles Through Palladium-catalyzed Reactions". Chem. Rev. 105 (7): 2873–2920. doi:10.1021/cr040639b. hdl:11573/232340. PMID 16011327.
Humphrey, G. R.; Kuethe, J. T. (2006). "Practical Methodologies for the Synthesis of Indoles". Chem. Rev. 106 (7): 2875–2911. doi:10.1021/cr0505270. PMID 16836303.
Taber, Douglass F.; Tirunahari, Pavan K. (September 2011). "Indole synthesis: a review and proposed classification". Tetrahedron. 67 (38): 7195–7210. doi:10.1016/j.tet.2011.06.040. PMC 4255418. PMID 25484459.
Collin, Gerd; Höke, Hartmut. "Indole". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a14_167. ISBN 978-3-527-30673-2.
Bratulescu, George (2008). "A new and efficient one-pot synthesis of indoles". Tetrahedron Letters. 49 (6): 984. doi:10.1016/j.tetlet.2007.12.015.
Diels, Otto; Reese, Johannes (1934). "Synthesen in der hydroaromatischen Reihe. XX. Über die Anlagerung von Acetylen-dicarbonsäureester an Hydrazobenzol" [Syntheses in the hydroaromatic series. XX. The addition of acetylene dicarboxylic acid ester to hydrazobenzene]. Justus Liebig's Annalen der Chemie. 511: 168. doi:10.1002/jlac.19345110114.
Huntress, Ernest H.; Bornstein, Joseph; Hearon, William M. (1956). "An Extension of the Diels-Reese Reaction". J. Am. Chem. Soc. 78 (10): 2225. Bibcode:1956JAChS..78.2225H. doi:10.1021/ja01591a055.
James, P. N.; Snyder, H. R. (1959). "Indole-3-aldehyde". Organic Syntheses. 39: 30. doi:10.15227/orgsyn.039.0030.
Noland, W. E.; Rush, K. R.; Smith, L. R. (1966). "Nitration of Indoles. IV. The Nitration of 2-Phenylindole". J. Org. Chem. 31: 65–69. doi:10.1021/jo01339a013.
Heaney, H.; Ley, S. V. (1974). "1-Benzylindole". Organic Syntheses. 54: 58. doi:10.15227/orgsyn.054.0058.
Bergman, J.; Venemalm, L. (1992). "Efficient synthesis of 2-chloro-, 2-bromo-, and 2-iodoindole". J. Org. Chem. 57 (8): 2495. doi:10.1021/jo00034a058.
Katritzky, Alan R.; Li, Jianqing; Stevens, Christian V. (1995). "Facile Synthesis of 2-Substituted Indoles and Indolo[3,2-b]carbazoles from 2-(Benzotriazol-1-ylmethyl)indole". J. Org. Chem. 60 (11): 3401–3404. doi:10.1021/jo00116a026.
Lynch, S. M.; Bur, S. K.; Padwa, A. (2002). "Intramolecular Amidofuran Cycloadditions across an Indole π-Bond: An Efficient Approach to the Aspidosperma and Strychnos ABCE Core". Org. Lett. 4 (26): 4643–5. doi:10.1021/ol027024q. PMID 12489950.
Cox, E. D.; Cook, J. M. (1995). "The Pictet-Spengler condensation: a new direction for an old reaction". Chemical Reviews. 95 (6): 1797–1842. doi:10.1021/cr00038a004.
Gremmen, C.; Willemse, B.; Wanner, M. J.; Koomen, G.-J. (2000). "Enantiopure Tetrahydro-β-carbolines via Pictet–Spengler Reactions with N-Sulfinyl Tryptamines". Org. Lett. 2 (13): 1955–1958. doi:10.1021/ol006034t. PMID 10891200.
Larghi, Enrique L.; Amongero, Marcela; Bracca, Andrea B. J.; Kaufman, Teodoro S. (2005). "The intermolecular Pictet–Spengler condensation with chiral carbonyl derivatives in the stereoselective syntheses of optically-active isoquinoline and indole alkaloids". Arkivoc. RL-1554K (12): 98–153. doi:10.3998/ark.5550190.0006.c09. hdl:2027/spo.5550190.0006.c09.
Bonnet, D.; Ganesan, A. (2002). "Solid-Phase Synthesis of Tetrahydro-β-carbolinehydantoins via the N-Acyliminium Pictet–Spengler Reaction and Cyclative Cleavage". J. Comb. Chem. 4 (6): 546–548. doi:10.1021/cc020026h. PMID 12425597.

elsevier.com (Global: 365^th place; English: 372^nd place)

linkinghub.elsevier.com

Taber, Douglass F.; Tirunahari, Pavan K. (September 2011). "Indole synthesis: a review and proposed classification". Tetrahedron. 67 (38): 7195–7210. doi:10.1016/j.tet.2011.06.040. PMC 4255418. PMID 25484459.

hathitrust.org (Global: 296^th place; English: 153^rd place)

babel.hathitrust.org

Baeyer, A.; Emmerling, A. (1869). "Synthese des Indols" [Synthesis of indole]. Berichte der Deutschen Chemischen Gesellschaft. 2: 679–682. doi:10.1002/cber.186900201268.

hdl.handle.net (Global: 66^th place; English: 34^th place)

Cacchi, S.; Fabrizi, G. (2005). "Synthesis and Functionalization of Indoles Through Palladium-catalyzed Reactions". Chem. Rev. 105 (7): 2873–2920. doi:10.1021/cr040639b. hdl:11573/232340. PMID 16011327.
Larghi, Enrique L.; Amongero, Marcela; Bracca, Andrea B. J.; Kaufman, Teodoro S. (2005). "The intermolecular Pictet–Spengler condensation with chiral carbonyl derivatives in the stereoselective syntheses of optically-active isoquinoline and indole alkaloids". Arkivoc. RL-1554K (12): 98–153. doi:10.3998/ark.5550190.0006.c09. hdl:2027/spo.5550190.0006.c09.

hmdb.ca (Global: low place; English: low place)

"3-Indolepropionic acid". Human Metabolome Database. University of Alberta. Retrieved 12 June 2018.

jioavatar.com (Global: low place; English: low place)

Ahmad, Shabee (2025). "Indole Derivatives as Anticancer Agent: Recent Developments". JioaVatar.

nih.gov (Global: 5^th place; English: 5^th place)

pubmed.ncbi.nlm.nih.gov

Oswald, Iain W. H.; Paryani, Twinkle R.; Sosa, Manuel E.; Ojeda, Marcos A.; Altenbernd, Mark R.; Grandy, Jonathan J.; Shafer, Nathan S.; Ngo, Kim; Peat, Jack R.; Melshenker, Bradley G.; Skelly, Ian; Koby, Kevin A.; Page, Michael F. Z.; Martin, Thomas J. (2023-10-12). "Minor, Nonterpenoid Volatile Compounds Drive the Aroma Differences of Exotic Cannabis". ACS Omega. 8 (42): 39203–39216. doi:10.1021/acsomega.3c04496. ISSN 2470-1343. PMC 10601067. PMID 37901519.
Liu, Yuping; Miao, Zhiwei; Guan, Wei; Sun, Baoguo (26 March 2012). "Analysis of Organic Volatile Flavor Compounds in Fermented Stinky Tofu Using SPME with Different Fiber Coatings". Molecules. 17 (4): 3708–3722. doi:10.3390/molecules17043708. PMC 6268145. PMID 22450681.
Lee, Jung Goo (21 October 2019). "The Neuroprotective Effects of Melatonin: Possible Role in the Pathophysiology of Neuropsychiatric Disease". Brain Sciences. 9 (285): 285. doi:10.3390/brainsci9100285. PMC 6826722. PMID 31640239.
Lee, Jin-Hyung; Lee, Jintae (2010). "Indole as an intercellular signal in microbial communities". FEMS Microbiology Reviews. 34 (4): 426–44. doi:10.1111/j.1574-6976.2009.00204.x. ISSN 0168-6445. PMID 20070374.
Zhang LS, Davies SS (April 2016). "Microbial metabolism of dietary components to bioactive metabolites: opportunities for new therapeutic interventions". Genome Med. 8 (1): 46. doi:10.1186/s13073-016-0296-x. PMC 4840492. PMID 27102537. Lactobacillus spp. convert tryptophan to indole-3-aldehyde (I3A) through unidentified enzymes [125]. Clostridium sporogenes convert tryptophan to IPA [6], likely via a tryptophan deaminase. ... IPA also potently scavenges hydroxyl radicals
Table 2: Microbial metabolites: their synthesis, mechanisms of action, and effects on health and disease
Figure 1: Molecular mechanisms of action of indole and its metabolites on host physiology and disease
Wikoff WR, Anfora AT, Liu J, Schultz PG, Lesley SA, Peters EC, Siuzdak G (March 2009). "Metabolomics analysis reveals large effects of gut microflora on mammalian blood metabolites". Proc. Natl. Acad. Sci. U.S.A. 106 (10): 3698–3703. Bibcode:2009PNAS..106.3698W. doi:10.1073/pnas.0812874106. PMC 2656143. PMID 19234110. Production of IPA was shown to be completely dependent on the presence of gut microflora and could be established by colonization with the bacterium Clostridium sporogenes.
IPA metabolism diagram
Chyan YJ, Poeggeler B, Omar RA, Chain DG, Frangione B, Ghiso J, Pappolla MA (July 1999). "Potent neuroprotective properties against the Alzheimer beta-amyloid by an endogenous melatonin-related indole structure, indole-3-propionic acid". J. Biol. Chem. 274 (31): 21937–21942. doi:10.1074/jbc.274.31.21937. PMID 10419516. S2CID 6630247. [Indole-3-propionic acid (IPA)] has previously been identified in the plasma and cerebrospinal fluid of humans, but its functions are not known. ... In kinetic competition experiments using free radical-trapping agents, the capacity of IPA to scavenge hydroxyl radicals exceeded that of melatonin, an indoleamine considered to be the most potent naturally occurring scavenger of free radicals. In contrast with other antioxidants, IPA was not converted to reactive intermediates with pro-oxidant activity.
Ehmann, Axel (1977-02-11). "The van URK-Salkowski reagent — a sensitive and specific chromogenic reagent for silica gel thin-layer chromatographic detection and identification of indole derivatives". Journal of Chromatography A. 132 (2): 267–276. doi:10.1016/S0021-9673(00)89300-0. ISSN 0021-9673. PMID 188858.
Darkoh, Charles; Chappell, Cynthia; Gonzales, Christopher; Okhuysen, Pablo (December 2015). Schloss, P. D. (ed.). "A Rapid and Specific Method for the Detection of Indole in Complex Biological Samples". Applied and Environmental Microbiology. 81 (23): 8093–8097. Bibcode:2015ApEnM..81.8093D. doi:10.1128/AEM.02787-15. ISSN 0099-2240. PMC 4651089. PMID 26386049.
Gilbert, Sarah; Xu, Jenny; Acosta, Kenneth; Poulev, Alexander; Lebeis, Sarah; Lam, Eric (2018). "Bacterial Production of Indole Related Compounds Reveals Their Role in Association Between Duckweeds and Endophytes". Frontiers in Chemistry. 6: 265. Bibcode:2018FrCh....6..265G. doi:10.3389/fchem.2018.00265. ISSN 2296-2646. PMC 6052042. PMID 30050896.
Matulis, Paulius; Kutraite, Ingrida; Augustiniene, Ernesta; Valanciene, Egle; Jonuskiene, Ilona; Malys, Naglis (January 2022). "Development and Characterization of Indole-Responsive Whole-Cell Biosensor Based on the Inducible Gene Expression System from Pseudomonas putida KT2440". International Journal of Molecular Sciences. 23 (9): 4649. doi:10.3390/ijms23094649. ISSN 1422-0067. PMC 9105386. PMID 35563040.
Ramesh, Deepthi; Joji, Annu; Vijayakumar, Balaji Gowrivel; Sethumadhavan, Aiswarya; Mani, Maheswaran; Kannan, Tharanikkarasu (15 July 2020). "Indole chalcones: Design, synthesis, in vitro and in silico evaluation against Mycobacterium tuberculosis". European Journal of Medicinal Chemistry. 198 112358. doi:10.1016/j.ejmech.2020.112358. ISSN 0223-5234. PMID 32361610. S2CID 218490655.
Qin, Hua-Li; Liu, Jing; Fang, Wan-Yin; Ravindar, L.; Rakesh, K. P. (15 May 2020). "Indole-based derivatives as potential antibacterial activity against methicillin-resistance Staphylococcus aureus (MRSA)". European Journal of Medicinal Chemistry. 194 112245. doi:10.1016/j.ejmech.2020.112245. ISSN 0223-5234. PMID 32220687. S2CID 214695328.
Thanikachalam, Punniyakoti Veeraveedu; Maurya, Rahul Kumar; Garg, Vishali; Monga, Vikramdeep (15 October 2019). "An insight into the medicinal perspective of synthetic analogs of indole: A review". European Journal of Medicinal Chemistry. 180: 562–612. doi:10.1016/j.ejmech.2019.07.019. ISSN 0223-5234. PMID 31344615. S2CID 198911553.
Kumari, Archana; Singh, Rajesh K. (1 August 2019). "Medicinal chemistry of indole derivatives: Current to future therapeutic prospectives". Bioorganic Chemistry. 89 103021. doi:10.1016/j.bioorg.2019.103021. ISSN 0045-2068. PMID 31176854. S2CID 182950054.
Jia, Yanshu; Wen, Xiaoyue; Gong, Yufeng; Wang, Xuefeng (15 August 2020). "Current scenario of indole derivatives with potential anti-drug-resistant cancer activity". European Journal of Medicinal Chemistry. 200 112359. doi:10.1016/j.ejmech.2020.112359. ISSN 0223-5234. PMID 32531682. S2CID 219021072.
Cacchi, S.; Fabrizi, G. (2005). "Synthesis and Functionalization of Indoles Through Palladium-catalyzed Reactions". Chem. Rev. 105 (7): 2873–2920. doi:10.1021/cr040639b. hdl:11573/232340. PMID 16011327.
Humphrey, G. R.; Kuethe, J. T. (2006). "Practical Methodologies for the Synthesis of Indoles". Chem. Rev. 106 (7): 2875–2911. doi:10.1021/cr0505270. PMID 16836303.
Taber, Douglass F.; Tirunahari, Pavan K. (September 2011). "Indole synthesis: a review and proposed classification". Tetrahedron. 67 (38): 7195–7210. doi:10.1016/j.tet.2011.06.040. PMC 4255418. PMID 25484459.
Lynch, S. M.; Bur, S. K.; Padwa, A. (2002). "Intramolecular Amidofuran Cycloadditions across an Indole π-Bond: An Efficient Approach to the Aspidosperma and Strychnos ABCE Core". Org. Lett. 4 (26): 4643–5. doi:10.1021/ol027024q. PMID 12489950.
Gremmen, C.; Willemse, B.; Wanner, M. J.; Koomen, G.-J. (2000). "Enantiopure Tetrahydro-β-carbolines via Pictet–Spengler Reactions with N-Sulfinyl Tryptamines". Org. Lett. 2 (13): 1955–1958. doi:10.1021/ol006034t. PMID 10891200.
Bonnet, D.; Ganesan, A. (2002). "Solid-Phase Synthesis of Tetrahydro-β-carbolinehydantoins via the N-Acyliminium Pictet–Spengler Reaction and Cyclative Cleavage". J. Comb. Chem. 4 (6): 546–548. doi:10.1021/cc020026h. PMID 12425597.

ncbi.nlm.nih.gov

Purves, Dale; Augustine, George J; Fitzpatrick, David; Katz, Lawrence C; LaMantia, Anthony-Samuel; McNamara, James O; Williams, S Mark. "Olfactory Perception in Humans". Olfactory Perception in Humans. Retrieved 20 October 2020.
Oswald, Iain W. H.; Paryani, Twinkle R.; Sosa, Manuel E.; Ojeda, Marcos A.; Altenbernd, Mark R.; Grandy, Jonathan J.; Shafer, Nathan S.; Ngo, Kim; Peat, Jack R.; Melshenker, Bradley G.; Skelly, Ian; Koby, Kevin A.; Page, Michael F. Z.; Martin, Thomas J. (2023-10-12). "Minor, Nonterpenoid Volatile Compounds Drive the Aroma Differences of Exotic Cannabis". ACS Omega. 8 (42): 39203–39216. doi:10.1021/acsomega.3c04496. ISSN 2470-1343. PMC 10601067. PMID 37901519.
Liu, Yuping; Miao, Zhiwei; Guan, Wei; Sun, Baoguo (26 March 2012). "Analysis of Organic Volatile Flavor Compounds in Fermented Stinky Tofu Using SPME with Different Fiber Coatings". Molecules. 17 (4): 3708–3722. doi:10.3390/molecules17043708. PMC 6268145. PMID 22450681.
Lee, Jung Goo (21 October 2019). "The Neuroprotective Effects of Melatonin: Possible Role in the Pathophysiology of Neuropsychiatric Disease". Brain Sciences. 9 (285): 285. doi:10.3390/brainsci9100285. PMC 6826722. PMID 31640239.
Zhang LS, Davies SS (April 2016). "Microbial metabolism of dietary components to bioactive metabolites: opportunities for new therapeutic interventions". Genome Med. 8 (1): 46. doi:10.1186/s13073-016-0296-x. PMC 4840492. PMID 27102537. Lactobacillus spp. convert tryptophan to indole-3-aldehyde (I3A) through unidentified enzymes [125]. Clostridium sporogenes convert tryptophan to IPA [6], likely via a tryptophan deaminase. ... IPA also potently scavenges hydroxyl radicals
Table 2: Microbial metabolites: their synthesis, mechanisms of action, and effects on health and disease
Figure 1: Molecular mechanisms of action of indole and its metabolites on host physiology and disease
Wikoff WR, Anfora AT, Liu J, Schultz PG, Lesley SA, Peters EC, Siuzdak G (March 2009). "Metabolomics analysis reveals large effects of gut microflora on mammalian blood metabolites". Proc. Natl. Acad. Sci. U.S.A. 106 (10): 3698–3703. Bibcode:2009PNAS..106.3698W. doi:10.1073/pnas.0812874106. PMC 2656143. PMID 19234110. Production of IPA was shown to be completely dependent on the presence of gut microflora and could be established by colonization with the bacterium Clostridium sporogenes.
IPA metabolism diagram
Darkoh, Charles; Chappell, Cynthia; Gonzales, Christopher; Okhuysen, Pablo (December 2015). Schloss, P. D. (ed.). "A Rapid and Specific Method for the Detection of Indole in Complex Biological Samples". Applied and Environmental Microbiology. 81 (23): 8093–8097. Bibcode:2015ApEnM..81.8093D. doi:10.1128/AEM.02787-15. ISSN 0099-2240. PMC 4651089. PMID 26386049.
Gilbert, Sarah; Xu, Jenny; Acosta, Kenneth; Poulev, Alexander; Lebeis, Sarah; Lam, Eric (2018). "Bacterial Production of Indole Related Compounds Reveals Their Role in Association Between Duckweeds and Endophytes". Frontiers in Chemistry. 6: 265. Bibcode:2018FrCh....6..265G. doi:10.3389/fchem.2018.00265. ISSN 2296-2646. PMC 6052042. PMID 30050896.
Matulis, Paulius; Kutraite, Ingrida; Augustiniene, Ernesta; Valanciene, Egle; Jonuskiene, Ilona; Malys, Naglis (January 2022). "Development and Characterization of Indole-Responsive Whole-Cell Biosensor Based on the Inducible Gene Expression System from Pseudomonas putida KT2440". International Journal of Molecular Sciences. 23 (9): 4649. doi:10.3390/ijms23094649. ISSN 1422-0067. PMC 9105386. PMID 35563040.
Taber, Douglass F.; Tirunahari, Pavan K. (September 2011). "Indole synthesis: a review and proposed classification". Tetrahedron. 67 (38): 7195–7210. doi:10.1016/j.tet.2011.06.040. PMC 4255418. PMID 25484459.

nsp-sun.com (Global: low place; English: low place)

"Indol NSP" (PDF).

orgsyn.org (Global: 3,535^th place; English: 4,321^st place)

James, P. N.; Snyder, H. R. (1959). "Indole-3-aldehyde". Organic Syntheses. 39: 30. doi:10.15227/orgsyn.039.0030.
Heaney, H.; Ley, S. V. (1974). "1-Benzylindole". Organic Syntheses. 54: 58. doi:10.15227/orgsyn.054.0058.

scentsandflavors.com (Global: low place; English: low place)

"indole". Scents and Flavors. Scents and Flavors. Retrieved 29 March 2026.
"indole". Scents and Flavors. Scents and Flavors. Retrieved 29 March 2026.

sciencedirect.com (Global: 137^th place; English: 146^th place)

Ehmann, Axel (1977-02-11). "The van URK-Salkowski reagent — a sensitive and specific chromogenic reagent for silica gel thin-layer chromatographic detection and identification of indole derivatives". Journal of Chromatography A. 132 (2): 267–276. doi:10.1016/S0021-9673(00)89300-0. ISSN 0021-9673. PMID 188858.

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Chyan YJ, Poeggeler B, Omar RA, Chain DG, Frangione B, Ghiso J, Pappolla MA (July 1999). "Potent neuroprotective properties against the Alzheimer beta-amyloid by an endogenous melatonin-related indole structure, indole-3-propionic acid". J. Biol. Chem. 274 (31): 21937–21942. doi:10.1074/jbc.274.31.21937. PMID 10419516. S2CID 6630247. [Indole-3-propionic acid (IPA)] has previously been identified in the plasma and cerebrospinal fluid of humans, but its functions are not known. ... In kinetic competition experiments using free radical-trapping agents, the capacity of IPA to scavenge hydroxyl radicals exceeded that of melatonin, an indoleamine considered to be the most potent naturally occurring scavenger of free radicals. In contrast with other antioxidants, IPA was not converted to reactive intermediates with pro-oxidant activity.
Ramesh, Deepthi; Joji, Annu; Vijayakumar, Balaji Gowrivel; Sethumadhavan, Aiswarya; Mani, Maheswaran; Kannan, Tharanikkarasu (15 July 2020). "Indole chalcones: Design, synthesis, in vitro and in silico evaluation against Mycobacterium tuberculosis". European Journal of Medicinal Chemistry. 198 112358. doi:10.1016/j.ejmech.2020.112358. ISSN 0223-5234. PMID 32361610. S2CID 218490655.
Qin, Hua-Li; Liu, Jing; Fang, Wan-Yin; Ravindar, L.; Rakesh, K. P. (15 May 2020). "Indole-based derivatives as potential antibacterial activity against methicillin-resistance Staphylococcus aureus (MRSA)". European Journal of Medicinal Chemistry. 194 112245. doi:10.1016/j.ejmech.2020.112245. ISSN 0223-5234. PMID 32220687. S2CID 214695328.
Thanikachalam, Punniyakoti Veeraveedu; Maurya, Rahul Kumar; Garg, Vishali; Monga, Vikramdeep (15 October 2019). "An insight into the medicinal perspective of synthetic analogs of indole: A review". European Journal of Medicinal Chemistry. 180: 562–612. doi:10.1016/j.ejmech.2019.07.019. ISSN 0223-5234. PMID 31344615. S2CID 198911553.
Kumari, Archana; Singh, Rajesh K. (1 August 2019). "Medicinal chemistry of indole derivatives: Current to future therapeutic prospectives". Bioorganic Chemistry. 89 103021. doi:10.1016/j.bioorg.2019.103021. ISSN 0045-2068. PMID 31176854. S2CID 182950054.
Jia, Yanshu; Wen, Xiaoyue; Gong, Yufeng; Wang, Xuefeng (15 August 2020). "Current scenario of indole derivatives with potential anti-drug-resistant cancer activity". European Journal of Medicinal Chemistry. 200 112359. doi:10.1016/j.ejmech.2020.112359. ISSN 0223-5234. PMID 32531682. S2CID 219021072.

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Oswald, Iain W. H.; Paryani, Twinkle R.; Sosa, Manuel E.; Ojeda, Marcos A.; Altenbernd, Mark R.; Grandy, Jonathan J.; Shafer, Nathan S.; Ngo, Kim; Peat, Jack R.; Melshenker, Bradley G.; Skelly, Ian; Koby, Kevin A.; Page, Michael F. Z.; Martin, Thomas J. (2023-10-12). "Minor, Nonterpenoid Volatile Compounds Drive the Aroma Differences of Exotic Cannabis". ACS Omega. 8 (42): 39203–39216. doi:10.1021/acsomega.3c04496. ISSN 2470-1343. PMC 10601067. PMID 37901519.
Lee, Jin-Hyung; Lee, Jintae (2010). "Indole as an intercellular signal in microbial communities". FEMS Microbiology Reviews. 34 (4): 426–44. doi:10.1111/j.1574-6976.2009.00204.x. ISSN 0168-6445. PMID 20070374.
Ehmann, Axel (1977-02-11). "The van URK-Salkowski reagent — a sensitive and specific chromogenic reagent for silica gel thin-layer chromatographic detection and identification of indole derivatives". Journal of Chromatography A. 132 (2): 267–276. doi:10.1016/S0021-9673(00)89300-0. ISSN 0021-9673. PMID 188858.
Darkoh, Charles; Chappell, Cynthia; Gonzales, Christopher; Okhuysen, Pablo (December 2015). Schloss, P. D. (ed.). "A Rapid and Specific Method for the Detection of Indole in Complex Biological Samples". Applied and Environmental Microbiology. 81 (23): 8093–8097. Bibcode:2015ApEnM..81.8093D. doi:10.1128/AEM.02787-15. ISSN 0099-2240. PMC 4651089. PMID 26386049.
Gilbert, Sarah; Xu, Jenny; Acosta, Kenneth; Poulev, Alexander; Lebeis, Sarah; Lam, Eric (2018). "Bacterial Production of Indole Related Compounds Reveals Their Role in Association Between Duckweeds and Endophytes". Frontiers in Chemistry. 6: 265. Bibcode:2018FrCh....6..265G. doi:10.3389/fchem.2018.00265. ISSN 2296-2646. PMC 6052042. PMID 30050896.
Matulis, Paulius; Kutraite, Ingrida; Augustiniene, Ernesta; Valanciene, Egle; Jonuskiene, Ilona; Malys, Naglis (January 2022). "Development and Characterization of Indole-Responsive Whole-Cell Biosensor Based on the Inducible Gene Expression System from Pseudomonas putida KT2440". International Journal of Molecular Sciences. 23 (9): 4649. doi:10.3390/ijms23094649. ISSN 1422-0067. PMC 9105386. PMID 35563040.
Ramesh, Deepthi; Joji, Annu; Vijayakumar, Balaji Gowrivel; Sethumadhavan, Aiswarya; Mani, Maheswaran; Kannan, Tharanikkarasu (15 July 2020). "Indole chalcones: Design, synthesis, in vitro and in silico evaluation against Mycobacterium tuberculosis". European Journal of Medicinal Chemistry. 198 112358. doi:10.1016/j.ejmech.2020.112358. ISSN 0223-5234. PMID 32361610. S2CID 218490655.
Qin, Hua-Li; Liu, Jing; Fang, Wan-Yin; Ravindar, L.; Rakesh, K. P. (15 May 2020). "Indole-based derivatives as potential antibacterial activity against methicillin-resistance Staphylococcus aureus (MRSA)". European Journal of Medicinal Chemistry. 194 112245. doi:10.1016/j.ejmech.2020.112245. ISSN 0223-5234. PMID 32220687. S2CID 214695328.
Thanikachalam, Punniyakoti Veeraveedu; Maurya, Rahul Kumar; Garg, Vishali; Monga, Vikramdeep (15 October 2019). "An insight into the medicinal perspective of synthetic analogs of indole: A review". European Journal of Medicinal Chemistry. 180: 562–612. doi:10.1016/j.ejmech.2019.07.019. ISSN 0223-5234. PMID 31344615. S2CID 198911553.
Kumari, Archana; Singh, Rajesh K. (1 August 2019). "Medicinal chemistry of indole derivatives: Current to future therapeutic prospectives". Bioorganic Chemistry. 89 103021. doi:10.1016/j.bioorg.2019.103021. ISSN 0045-2068. PMID 31176854. S2CID 182950054.
Jia, Yanshu; Wen, Xiaoyue; Gong, Yufeng; Wang, Xuefeng (15 August 2020). "Current scenario of indole derivatives with potential anti-drug-resistant cancer activity". European Journal of Medicinal Chemistry. 200 112359. doi:10.1016/j.ejmech.2020.112359. ISSN 0223-5234. PMID 32531682. S2CID 219021072.

Indole (English Wikipedia)

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