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Record Information
Version5.0
StatusDetected and Quantified
Creation Date2006-05-22 14:17:47 UTC
Update Date2023-02-21 17:16:19 UTC
HMDB IDHMDB0002302
Secondary Accession Numbers
  • HMDB02302
Metabolite Identification
Common NameIndole-3-propionic acid
DescriptionIndole-3-propionic acid (IPA, indole-3-propionate, or indole propionic acid), is a reductive product of tryptophan formed by bacteria in the gastrointestinal tract of mammals and birds (PMID:29168502 ). It is endogenously produced by human microbiota and has only been detected in vivo (PMID:19234110 ). While many microbial metabolites produced in the gut are toxic or act as uremic toxins (when they are reabsorbed through the gut epithelia), indole-3-propionic acid is a very beneficial microbial metabolite (PMID:30914514 , 30862081 , 29238104 ). In limited studies, urinary IPA correlates positively with disease and it remains unclear if this represents host bacteria responding to pathology via the production of IPA, or intestinal permeability changes leading to higher absorption and excretion of IPA, or inflammatory changes within kidneys leading to high excretion of IPA (PMID:32132996 ). Indole-3-propionic acid is a remarkably strong antioxidant (PMID:10721080 ). It is an even more potent scavenger of hydroxyl radicals than melatonin, the most potent scavenger of hydroxyl radicals synthesized by the human body. Similar to melatonin but unlike other antioxidants, indole-3-propionic acid scavenges radicals without subsequently generating reactive and pro-oxidant intermediate compounds (PMID:9928448 , 10419516 ). Indole-3-propionic acid has been shown to prevent oxidative stress and the death of primary neurons and neuroblastoma cells exposed to the amyloid beta-protein in the form of amyloid fibrils, one of the most prominent neuropathologic features of Alzheimer's disease. 3-Indolepropionic acid also shows a strong level of neuroprotection in two other paradigms of oxidative stress. (PMID 10419516 ) More recently it has been found that higher indole-3-propionic acid levels in serum/plasma are associated with a reduced likelihood of type 2 diabetes and with higher levels of consumption of fibre-rich foods (PMID:28397877 ). Studies have shown that serum levels of indole-3-propionic acid are positively correlated with dietary fibre intake and negatively correlated with C-reactive protein levels (PMID:29795366 ). Indole-3-propionic acid is a marker for the presence of Clostridium sporogenes in the gut. Higher levels are associated with higher levels of Clostridium sporogenes (PMID:7378938 ). In addition to its useful physiological role in mammals, indole-3-propionic acid is a plant hormone with functions similar to indole-3-acetic acid (or IAA), the major plant auxin. Recent studies have shed some light on additional mechanisms of action of IPA. In the intestine, IPA could serve as a ligand to an adopted orphan nuclear receptor, Pregnane X receptor (PXR) and act as an anti-inflammatory agent (PMID:25065623 ). This property has allowed investigators to develop more potent analogs targeting PXR (PMID:32153125 ). Other tissues may also be targeted by IPA in a similar manner (PMID:31211619 ).
Structure
Data?1676999779
Synonyms
ValueSource
beta-(3-Indolyl)propionic acidChEBI
Indolepropionic acidChEBI
b-(3-Indolyl)propionateGenerator
b-(3-Indolyl)propionic acidGenerator
beta-(3-Indolyl)propionateGenerator
Β-(3-indolyl)propionateGenerator
Β-(3-indolyl)propionic acidGenerator
IndolepropionateGenerator
Indole-3-propionateGenerator
Indole propionateMeSH
Indole-3-propanoic acidMeSH
Indole-3-propionic acidChEBI
3-IndolepropionateGenerator, HMDB
1H-Indole-3-propionateHMDB
1H-Indole-3-propionic acidHMDB
3-(1H-indol-3-yl)PropanoateHMDB, Generator
3-(1H-Indol-3-yl)propanoic acidHMDB
3-(1H-indol-3-yl)PropionateHMDB
3-(1H-Indol-3-yl)propionic acidHMDB
3-(2-Carboxyethyl)-1H-indoleHMDB
3-(3-Indolyl)propanoateHMDB
3-(3-Indolyl)propanoic acidHMDB
3-(3-Indolyl)propionateHMDB
3-(3-Indolyl)propionic acidHMDB
b-Indole-3-propionateHMDB
b-Indole-3-propionic acidHMDB
b-IndolepropionateHMDB
b-Indolepropionic acidHMDB
beta-Indole-3-propionateHMDB
beta-Indole-3-propionic acidHMDB
beta-IndolepropionateHMDB
beta-Indolepropionic acidHMDB
IPAHMDB
3-Indolepropionic acidHMDB
1H-Indole-3-propanoic acidHMDB
3-(Indole-3-yl)propanoic acidHMDB
3-(Indole-3-yl)propionic acidHMDB
beta-(3-Indolyl)propanoic acidHMDB
beta-Indole-3-propanoic acidHMDB
beta-Indolepropanoic acidHMDB
β-(3-Indolyl)propanoic acidHMDB
β-Indole-3-propanoic acidHMDB
β-Indole-3-propionic acidHMDB
β-Indolepropanoic acidHMDB
β-Indolepropionic acidHMDB
Chemical FormulaC11H11NO2
Average Molecular Weight189.2105
Monoisotopic Molecular Weight189.078978601
IUPAC Name3-(1H-indol-3-yl)propanoic acid
Traditional Nameindolylpropionic acid
CAS Registry Number830-96-6
SMILES
OC(=O)CCC1=CNC2=C1C=CC=C2
InChI Identifier
InChI=1S/C11H11NO2/c13-11(14)6-5-8-7-12-10-4-2-1-3-9(8)10/h1-4,7,12H,5-6H2,(H,13,14)
InChI KeyGOLXRNDWAUTYKT-UHFFFAOYSA-N
Chemical Taxonomy
Description Belongs to the class of organic compounds known as indolyl carboxylic acids and derivatives. Indolyl carboxylic acids and derivatives are compounds containing a carboxylic acid chain (of at least 2 carbon atoms) linked to an indole ring.
KingdomOrganic compounds
Super ClassOrganoheterocyclic compounds
ClassIndoles and derivatives
Sub ClassIndolyl carboxylic acids and derivatives
Direct ParentIndolyl carboxylic acids and derivatives
Alternative Parents
Substituents
  • Indolyl carboxylic acid derivative
  • 3-alkylindole
  • Indole
  • Substituted pyrrole
  • Benzenoid
  • Heteroaromatic compound
  • Pyrrole
  • Azacycle
  • Monocarboxylic acid or derivatives
  • Carboxylic acid
  • Carboxylic acid derivative
  • Carbonyl group
  • Organopnictogen compound
  • Organooxygen compound
  • Organonitrogen compound
  • Organic oxygen compound
  • Organic nitrogen compound
  • Hydrocarbon derivative
  • Organic oxide
  • Aromatic heteropolycyclic compound
Molecular FrameworkAromatic heteropolycyclic compounds
External Descriptors
Ontology
Physiological effectNot Available
Disposition
ProcessNot Available
Role
Physical Properties
StateSolid
Experimental Molecular Properties
PropertyValueReference
Melting Point134 - 135 °CNot Available
Boiling PointNot AvailableNot Available
Water SolubilityNot AvailableNot Available
LogP1.75HANSCH,C ET AL. (1995)
Experimental Chromatographic PropertiesNot Available
Predicted Molecular Properties
PropertyValueSource
Water Solubility0.73 g/LALOGPS
logP2.04ALOGPS
logP2.15ChemAxon
logS-2.4ALOGPS
pKa (Strongest Acidic)4.8ChemAxon
Physiological Charge-1ChemAxon
Hydrogen Acceptor Count2ChemAxon
Hydrogen Donor Count2ChemAxon
Polar Surface Area53.09 ŲChemAxon
Rotatable Bond Count3ChemAxon
Refractivity53.05 m³·mol⁻¹ChemAxon
Polarizability20 ųChemAxon
Number of Rings2ChemAxon
BioavailabilityYesChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Predicted Chromatographic Properties

Predicted Collision Cross Sections

PredictorAdduct TypeCCS Value (Å2)Reference
DarkChem[M+H]+143.92631661259
DarkChem[M-H]-140.40231661259
DeepCCS[M+H]+137.68630932474
DeepCCS[M-H]-134.97130932474
DeepCCS[M-2H]-171.22430932474
DeepCCS[M+Na]+146.76230932474
AllCCS[M+H]+141.632859911
AllCCS[M+H-H2O]+137.332859911
AllCCS[M+NH4]+145.532859911
AllCCS[M+Na]+146.732859911
AllCCS[M-H]-142.832859911
AllCCS[M+Na-2H]-143.032859911
AllCCS[M+HCOO]-143.332859911

Predicted Kovats Retention Indices

Underivatized

MetaboliteSMILESKovats RI ValueColumn TypeReference
Indole-3-propionic acidOC(=O)CCC1=CNC2=C1C=CC=C23392.1Standard polar33892256
Indole-3-propionic acidOC(=O)CCC1=CNC2=C1C=CC=C21776.1Standard non polar33892256
Indole-3-propionic acidOC(=O)CCC1=CNC2=C1C=CC=C21984.6Semi standard non polar33892256

Derivatized

Derivative Name / StructureSMILESKovats RI ValueColumn TypeReference
Indole-3-propionic acid,1TMS,isomer #1C[Si](C)(C)OC(=O)CCC1=C[NH]C2=CC=CC=C122028.0Semi standard non polar33892256
Indole-3-propionic acid,1TMS,isomer #2C[Si](C)(C)N1C=C(CCC(=O)O)C2=CC=CC=C212074.8Semi standard non polar33892256
Indole-3-propionic acid,2TMS,isomer #1C[Si](C)(C)OC(=O)CCC1=CN([Si](C)(C)C)C2=CC=CC=C122059.2Semi standard non polar33892256
Indole-3-propionic acid,2TMS,isomer #1C[Si](C)(C)OC(=O)CCC1=CN([Si](C)(C)C)C2=CC=CC=C122030.8Standard non polar33892256
Indole-3-propionic acid,2TMS,isomer #1C[Si](C)(C)OC(=O)CCC1=CN([Si](C)(C)C)C2=CC=CC=C122245.2Standard polar33892256
Indole-3-propionic acid,1TBDMS,isomer #1CC(C)(C)[Si](C)(C)OC(=O)CCC1=C[NH]C2=CC=CC=C122288.2Semi standard non polar33892256
Indole-3-propionic acid,1TBDMS,isomer #2CC(C)(C)[Si](C)(C)N1C=C(CCC(=O)O)C2=CC=CC=C212334.4Semi standard non polar33892256
Indole-3-propionic acid,2TBDMS,isomer #1CC(C)(C)[Si](C)(C)OC(=O)CCC1=CN([Si](C)(C)C(C)(C)C)C2=CC=CC=C122522.1Semi standard non polar33892256
Indole-3-propionic acid,2TBDMS,isomer #1CC(C)(C)[Si](C)(C)OC(=O)CCC1=CN([Si](C)(C)C(C)(C)C)C2=CC=CC=C122470.3Standard non polar33892256
Indole-3-propionic acid,2TBDMS,isomer #1CC(C)(C)[Si](C)(C)OC(=O)CCC1=CN([Si](C)(C)C(C)(C)C)C2=CC=CC=C122471.4Standard polar33892256
Spectra

GC-MS Spectra

Spectrum TypeDescriptionSplash KeyDeposition DateSourceView
Experimental GC-MSGC-MS Spectrum - Indole-3-propionic acid EI-B (Non-derivatized)splash10-001i-1900000000-7964cf38946a23d631042017-09-12HMDB team, MONA, MassBankView Spectrum
Experimental GC-MSGC-MS Spectrum - Indole-3-propionic acid EI-B (Non-derivatized)splash10-001i-1900000000-7964cf38946a23d631042018-05-18HMDB team, MONA, MassBankView Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - Indole-3-propionic acid GC-MS (Non-derivatized) - 70eV, Positivesplash10-002f-1900000000-79b70b4d80349fed40a22017-08-28Wishart LabView Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - Indole-3-propionic acid GC-MS (1 TMS) - 70eV, Positivesplash10-00dl-8910000000-cc3bf52f2cbb339eea4a2017-10-06Wishart LabView Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - Indole-3-propionic acid GC-MS (Non-derivatized) - 70eV, PositiveNot Available2021-10-12Wishart LabView Spectrum
MSMass Spectrum (Electron Ionization)splash10-001i-1900000000-de72f9061ea0bb241ef72015-03-01Not AvailableView Spectrum

MS/MS Spectra

Spectrum TypeDescriptionSplash KeyDeposition DateSourceView
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid Quattro_QQQ 10V, Positive-QTOF (Annotated)splash10-004i-0900000000-5bf41cc0642ca12d91dd2012-07-25HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid Quattro_QQQ 25V, Positive-QTOF (Annotated)splash10-004i-0900000000-2bdd32c86cd63a03b7392012-07-25HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid Quattro_QQQ 40V, Positive-QTOF (Annotated)splash10-004i-8900000000-fa98f64c6c35db6c34252012-07-25HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid EI-B (Unknown) , Positive-QTOFsplash10-001i-1900000000-7964cf38946a23d631042012-08-31HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid LC-ESI-IT , positive-QTOFsplash10-00e9-0900000000-aa04863f4b124d6171682017-09-14HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid , positive-QTOFsplash10-001i-1900000000-c3c14c76cdb38c3798f02017-09-14HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid 20V, Positive-QTOFsplash10-001i-1900000000-db653a92384089e7272c2021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid 35V, Positive-QTOFsplash10-001i-0900000000-2837a9689ebb97e17c892021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid 40V, Negative-QTOFsplash10-03di-9400000000-20084f0045f0393dcaad2021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid 10V, Negative-QTOFsplash10-0a4i-9500000000-d39c747b7db2e42acefc2021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid 10V, Positive-QTOFsplash10-001i-0900000000-8927c2758d647a804f4a2021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid 20V, Negative-QTOFsplash10-0a4i-9300000000-282c233baa3c0e5bf3652021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid 40V, Positive-QTOFsplash10-001i-4900000000-1e1179cded69a29a50472021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid 20V, Negative-QTOFsplash10-0a4i-9300000000-0aaa5de6ae1a4aafa6612021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid 10V, Positive-QTOFsplash10-001i-0900000000-1b79a66b12c3205108c52021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid 35V, Negative-QTOFsplash10-0aor-6900000000-909aa5100e4655d542672021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid 40V, Negative-QTOFsplash10-05mo-9600000000-e85aca97bdac26c3d2582021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid 40V, Positive-QTOFsplash10-003r-4900000000-29142c5171637b4d5e5f2021-09-20HMDB team, MONAView Spectrum
Experimental LC-MS/MSLC-MS/MS Spectrum - Indole-3-propionic acid 10V, Negative-QTOFsplash10-0a4i-9600000000-bc2ddd9f185d76d60d502021-09-20HMDB team, MONAView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - Indole-3-propionic acid 10V, Positive-QTOFsplash10-006x-0900000000-4be398aaf9b9276372282017-07-26Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - Indole-3-propionic acid 20V, Positive-QTOFsplash10-0006-0900000000-5f65be50e34cc07d1a772017-07-26Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - Indole-3-propionic acid 40V, Positive-QTOFsplash10-00lu-2900000000-747697a81c30bbf35e012017-07-26Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - Indole-3-propionic acid 10V, Negative-QTOFsplash10-000i-0900000000-76970d017d781fd874742017-07-26Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - Indole-3-propionic acid 20V, Negative-QTOFsplash10-000l-1900000000-35d9289d5e0f2905c29d2017-07-26Wishart LabView Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - Indole-3-propionic acid 40V, Negative-QTOFsplash10-052f-9700000000-8a8af8b32271e2d2eef02017-07-26Wishart LabView Spectrum

NMR Spectra

Spectrum TypeDescriptionDeposition DateSourceView
Experimental 1D NMR1H NMR Spectrum (1D, 500 MHz, H2O, experimental)2021-10-10Wishart LabView Spectrum

IR Spectra

Spectrum TypeDescriptionDeposition DateSourceView
Predicted IR SpectrumIR Ion Spectrum (Quadrupole Ion Trap, ESI+, Adduct: [M+Na]+)2022-02-11FELIX labView Spectrum
Predicted IR SpectrumIR Ion Spectrum (Quadrupole Ion Trap, ESI+, Adduct: [M+H]+)2022-02-11FELIX labView Spectrum
Predicted IR SpectrumIR Ion Spectrum (Quadrupole Ion Trap, ESI-, Adduct: [M-H]-)2022-02-11FELIX labView Spectrum
Predicted IR SpectrumIR Ion Spectrum (Predicted IRIS Spectrum, Adduct: [M-H]-)2023-02-03FELIX labView Spectrum
Predicted IR SpectrumIR Ion Spectrum (Predicted IRIS Spectrum, Adduct: [M+H]+)2023-02-03FELIX labView Spectrum
Predicted IR SpectrumIR Ion Spectrum (Predicted IRIS Spectrum, Adduct: [M+Na]+)2023-02-03FELIX labView Spectrum
Biological Properties
Cellular Locations
  • Membrane (predicted from logP)
Biospecimen Locations
  • Blood
  • Feces
  • Saliva
  • Urine
Tissue LocationsNot Available
Pathways
Normal Concentrations
BiospecimenStatusValueAgeSexConditionReferenceDetails
BloodDetected but not QuantifiedNot QuantifiedAdult (>18 years old)BothNormal details
BloodDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Female
Normal
details
BloodDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Female
Normal
details
BloodDetected but not QuantifiedNot QuantifiedAdult (>18 years old)BothNormal details
BloodDetected and Quantified0.481 (0.291 - 1.095) uMAdult (>18 years old)Not SpecifiedNormal details
BloodDetected but not QuantifiedNot QuantifiedNot AvailableNot AvailableNormal details
FecesDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
Normal
details
FecesDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
Normal
details
FecesDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
Normal
details
SalivaDetected but not QuantifiedNot QuantifiedAdult (>18 years old)BothNormal details
UrineDetected but not QuantifiedNot QuantifiedAdult (>18 years old)BothNormal details
Abnormal Concentrations
BiospecimenStatusValueAgeSexConditionReferenceDetails
BloodDetected but not QuantifiedNot QuantifiedAdult (>18 years old)BothHemodialysis patients with colon details
FecesDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
Colorectal cancer
details
FecesDetected but not QuantifiedNot QuantifiedAdult (>18 years old)Both
Colorectal cancer
details
FecesDetected but not QuantifiedNot QuantifiedAdult (>18 years old)BothColorectal Cancer details
SalivaDetected but not QuantifiedNot QuantifiedAdult (>18 years old)BothOral squamous cell carcinoma (OSCC) details
SalivaDetected but not QuantifiedNot QuantifiedAdult (>18 years old)BothOral leukoplakia (OLK) details
Associated Disorders and Diseases
Disease References
Colorectal cancer
  1. Brown DG, Rao S, Weir TL, O'Malia J, Bazan M, Brown RJ, Ryan EP: Metabolomics and metabolic pathway networks from human colorectal cancers, adjacent mucosa, and stool. Cancer Metab. 2016 Jun 6;4:11. doi: 10.1186/s40170-016-0151-y. eCollection 2016. [PubMed:27275383 ]
  2. Sinha R, Ahn J, Sampson JN, Shi J, Yu G, Xiong X, Hayes RB, Goedert JJ: Fecal Microbiota, Fecal Metabolome, and Colorectal Cancer Interrelations. PLoS One. 2016 Mar 25;11(3):e0152126. doi: 10.1371/journal.pone.0152126. eCollection 2016. [PubMed:27015276 ]
  3. Goedert JJ, Sampson JN, Moore SC, Xiao Q, Xiong X, Hayes RB, Ahn J, Shi J, Sinha R: Fecal metabolomics: assay performance and association with colorectal cancer. Carcinogenesis. 2014 Sep;35(9):2089-96. doi: 10.1093/carcin/bgu131. Epub 2014 Jul 18. [PubMed:25037050 ]
Associated OMIM IDs
DrugBank IDDB02758
Phenol Explorer Compound IDNot Available
FooDB IDFDB000941
KNApSAcK IDC00000115
Chemspider ID3613
KEGG Compound IDNot Available
BioCyc IDINDOLE-PROPIONATE
BiGG IDNot Available
Wikipedia Link3-Indolepropionic acid
METLIN ID6602
PubChem Compound3744
PDB IDNot Available
ChEBI ID43580
Food Biomarker OntologyNot Available
VMH IDIND3PPA
MarkerDB IDNot Available
Good Scents IDNot Available
References
Synthesis ReferenceJohnson, Herbert E.; Crosby, Donald G. 3-Indolepropionic acid. Journal of Organic Chemistry (1960), 25 569-71.
Material Safety Data Sheet (MSDS)Download (PDF)
General References
  1. Chyan YJ, Poeggeler B, Omar RA, Chain DG, Frangione B, Ghiso J, Pappolla MA: Potent neuroprotective properties against the Alzheimer beta-amyloid by an endogenous melatonin-related indole structure, indole-3-propionic acid. J Biol Chem. 1999 Jul 30;274(31):21937-42. [PubMed:10419516 ]
  2. Wikoff WR, Anfora AT, Liu J, Schultz PG, Lesley SA, Peters EC, Siuzdak G: Metabolomics analysis reveals large effects of gut microflora on mammalian blood metabolites. Proc Natl Acad Sci U S A. 2009 Mar 10;106(10):3698-703. doi: 10.1073/pnas.0812874106. Epub 2009 Feb 20. [PubMed:19234110 ]
  3. Reiter RJ, Guerrero JM, Garcia JJ, Acuna-Castroviejo D: Reactive oxygen intermediates, molecular damage, and aging. Relation to melatonin. Ann N Y Acad Sci. 1998 Nov 20;854:410-24. [PubMed:9928448 ]
  4. Kim WS, Gardan L, Rhim SL, Geider K: Erwinia pyrifoliae sp. nov., a novel pathogen that affects Asian pear trees (Pyrus pyrifolia Nakai) Int J Syst Bacteriol. 1999 Apr;49 Pt 2:899-905. doi: 10.1099/00207713-49-2-899. [PubMed:10319516 ]
  5. de Mello VD, Paananen J, Lindstrom J, Lankinen MA, Shi L, Kuusisto J, Pihlajamaki J, Auriola S, Lehtonen M, Rolandsson O, Bergdahl IA, Nordin E, Ilanne-Parikka P, Keinanen-Kiukaanniemi S, Landberg R, Eriksson JG, Tuomilehto J, Hanhineva K, Uusitupa M: Indolepropionic acid and novel lipid metabolites are associated with a lower risk of type 2 diabetes in the Finnish Diabetes Prevention Study. Sci Rep. 2017 Apr 11;7:46337. doi: 10.1038/srep46337. [PubMed:28397877 ]
  6. Dodd D, Spitzer MH, Van Treuren W, Merrill BD, Hryckowian AJ, Higginbottom SK, Le A, Cowan TM, Nolan GP, Fischbach MA, Sonnenburg JL: A gut bacterial pathway metabolizes aromatic amino acids into nine circulating metabolites. Nature. 2017 Nov 30;551(7682):648-652. doi: 10.1038/nature24661. Epub 2017 Nov 22. [PubMed:29168502 ]
  7. Jellet JJ, Forrest TP, Macdonald IA, Marrie TJ, Holdeman LV: Production of indole-3-propanoic acid and 3-(p-hydroxyphenyl)propanoic acid by Clostridium sporogenes: a convenient thin-layer chromatography detection system. Can J Microbiol. 1980 Apr;26(4):448-53. [PubMed:7378938 ]
  8. Tuomainen M, Lindstrom J, Lehtonen M, Auriola S, Pihlajamaki J, Peltonen M, Tuomilehto J, Uusitupa M, de Mello VD, Hanhineva K: Associations of serum indolepropionic acid, a gut microbiota metabolite, with type 2 diabetes and low-grade inflammation in high-risk individuals. Nutr Diabetes. 2018 May 25;8(1):35. doi: 10.1038/s41387-018-0046-9. [PubMed:29795366 ]
  9. Galligan JJ: Beneficial actions of microbiota-derived tryptophan metabolites. Neurogastroenterol Motil. 2018 Feb;30(2). doi: 10.1111/nmo.13283. [PubMed:29341448 ]
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