Record Information
Creation date2011-09-21 00:09:59 UTC
Update date2015-10-09 22:28:01 UTC
Primary IDFDB022200
Secondary Accession NumbersNot Available
Chemical Information
FooDB NameKynurenic acid
DescriptionKynurenic acid (KYNA) is a well-known endogenous antagonist of the glutamate ionotropic excitatory amino acid receptors N-methyl-D-aspartate (NMDA), alphaamino-3-hydroxy-5-methylisoxazole-4-propionic acid and kainate receptors and of the nicotine cholinergic subtype alpha 7 receptors. KYNA neuroprotective and anticonvulsive activities have been demonstrated in animal models of neurodegenerative diseases. Because of KYNA's neuromodulatory character, its involvement has been speculatively linked to the pathogenesis of a number of neurological conditions including those in the ageing process. Different patterns of abnormalities in various stages of KYNA metabolism in the CNS have been reported in Alzheimer's disease, Parkinson's disease and Huntington's disease. In HIV-1-infected patients and in patients with Lyme neuroborreliosis a marked rise of KYNA metabolism was seen. In the ageing process KYNA metabolism in the CNS of rats shows a characteristic pattern of changes throughout the life span. A marked increase of the KYNA content in the CNS occurs before the birth, followed by a dramatic decline on the day of birth. A low activity was seen during ontogenesis, and a slow and progressive enhancement occurs during maturation and ageing. This remarkable profile of KYNA metabolism alterations in the mammalian brain has been suggested to result from the development of the organisation of neuronal connections and synaptic plasticity, development of receptor recognition sites, maturation and ageing. There is significant evidence that KYNA can improve cognition and memory, but it has also been demonstrated that it interferes with working memory. Impairment of cognitive function in various neurodegenerative disorders is accompanied by profound reduction and/or elevation of KYNA metabolism. The view that enhancement of CNS KYNA levels could underlie cognitive decline is supported by the increased KYNA metabolism in Alzheimer's disease, by the increased KYNA metabolism in down's syndrome and the enhancement of KYNA function during the early stage of Huntington's disease. Kynurenic acid is the only endogenous N-methyl-D-aspartate (NMDA) receptor antagonist identified up to now, that mediates glutamatergic hypofunction. Schizophrenia is a disorder of dopaminergic neurotransmission, but modulation of the dopaminergic system by glutamatergic neurotransmission seems to play a key role. Despite the NMDA receptor antagonism, kynurenic acid also blocks, in lower doses, the nicotinergic acetycholine receptor, i.e., increased kynurenic acid levels can explain psychotic symptoms and cognitive deterioration. Kynurenic acid levels are described to be higher in the cerebrospinal fluid (CSF) and in critical central nervous system (CNS) regions of schizophrenics as compared to controls. (PMID: 17062375, 16088227) [HMDB]
CAS Number492-27-3
4-Hydroxy-2-quinolinecarboxylic acidChEBI
4-Hydroxyquinaldic acidChEBI
4-Hydroxyquinaldinic acidChEBI
4-Hydroxy-quinaldic acidHMDB
4-Hydroxyquinoline-2-carboxylic acidHMDB
Quinurenic acidHMDB
Acid, kynurenicMeSH, HMDB
4-hydroxy-2-Quinolinecarboxylic acidhmdb
4-hydroxy-Quinaldic acidhmdb
Kynurenic acidhmdb
Predicted Properties
Water Solubility0.95 g/LALOGPS
pKa (Strongest Acidic)3.17ChemAxon
pKa (Strongest Basic)-4.4ChemAxon
Physiological Charge-1ChemAxon
Hydrogen Acceptor Count4ChemAxon
Hydrogen Donor Count2ChemAxon
Polar Surface Area66.4 ŲChemAxon
Rotatable Bond Count1ChemAxon
Refractivity52.32 m³·mol⁻¹ChemAxon
Polarizability18.05 ųChemAxon
Number of Rings2ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Chemical FormulaC10H7NO3
IUPAC name4-oxo-1,4-dihydroquinoline-2-carboxylic acid
InChI IdentifierInChI=1S/C10H7NO3/c12-9-5-8(10(13)14)11-7-4-2-1-3-6(7)9/h1-5H,(H,11,12)(H,13,14)
Isomeric SMILESOC(=O)C1=CC(=O)C2=CC=CC=C2N1
Average Molecular Weight189.1675
Monoisotopic Molecular Weight189.042593095
Description Belongs to the class of organic compounds known as quinoline carboxylic acids. These are quinolines in which the quinoline ring system is substituted by a carboxyl group at one or more positions.
KingdomOrganic compounds
Super ClassOrganoheterocyclic compounds
ClassQuinolines and derivatives
Sub ClassQuinoline carboxylic acids
Direct ParentQuinoline carboxylic acids
Alternative Parents
  • Quinoline-2-carboxylic acid
  • Dihydroquinolone
  • Dihydroquinoline
  • Pyridine carboxylic acid
  • Pyridine carboxylic acid or derivatives
  • Pyridine
  • Benzenoid
  • Heteroaromatic compound
  • Vinylogous amide
  • Monocarboxylic acid or derivatives
  • Carboxylic acid
  • Azacycle
  • Carboxylic acid derivative
  • Hydrocarbon derivative
  • Organic oxide
  • Organopnictogen compound
  • Organooxygen compound
  • Organonitrogen compound
  • Organic oxygen compound
  • Organic nitrogen compound
  • Aromatic heteropolycyclic compound
Molecular FrameworkAromatic heteropolycyclic compounds
External Descriptors
Physiological effect

Health effect:


Route of exposure:


Biological location:


Industrial application:

Physico-Chemical Properties - Experimental
Physico-Chemical Properties - Experimental
Physical stateSolid
Physical DescriptionNot Available
Mass CompositionNot Available
Melting PointNot Available
Boiling PointNot Available
Experimental Water SolubilityNot Available
Experimental logPNot Available
Experimental pKaNot Available
Isoelectric pointNot Available
ChargeNot Available
Optical RotationNot Available
Spectroscopic UV DataNot Available
DensityNot Available
Refractive IndexNot Available
TypeDescriptionSplash KeyView
GC-MSKynurenic acid, non-derivatized, GC-MS Spectrumsplash10-0159-1985000000-f1c74ffc481c3d0faaa2Spectrum
GC-MSKynurenic acid, 2 TMS, GC-MS Spectrumsplash10-0159-3895000000-6ba2750c5a9d9754abccSpectrum
GC-MSKynurenic acid, non-derivatized, GC-MS Spectrumsplash10-0159-0498000000-3db9df2c3d8456d7ba63Spectrum
GC-MSKynurenic acid, non-derivatized, GC-MS Spectrumsplash10-0159-1985000000-f1c74ffc481c3d0faaa2Spectrum
GC-MSKynurenic acid, non-derivatized, GC-MS Spectrumsplash10-0159-3895000000-6ba2750c5a9d9754abccSpectrum
GC-MSKynurenic acid, non-derivatized, GC-MS Spectrumsplash10-0159-1895000000-e25b66b0b42d1928cc67Spectrum
Predicted GC-MSKynurenic acid, non-derivatized, Predicted GC-MS Spectrum - 70eV, Positivesplash10-02ga-1900000000-8c67ab2acdc02b88af2bSpectrum
Predicted GC-MSKynurenic acid, 1 TMS, Predicted GC-MS Spectrum - 70eV, Positivesplash10-00di-9740000000-a7c5c056d48055e0d44fSpectrum
Predicted GC-MSKynurenic acid, non-derivatized, Predicted GC-MS Spectrum - 70eV, PositiveNot AvailableSpectrum
Predicted GC-MSKynurenic acid, TMS_1_2, Predicted GC-MS Spectrum - 70eV, PositiveNot AvailableSpectrum
Predicted GC-MSKynurenic acid, TBDMS_1_1, Predicted GC-MS Spectrum - 70eV, PositiveNot AvailableSpectrum
Predicted GC-MSKynurenic acid, TBDMS_1_2, Predicted GC-MS Spectrum - 70eV, PositiveNot AvailableSpectrum
TypeDescriptionSplash KeyView
MS/MSLC-MS/MS Spectrum - Quattro_QQQ 10V, Positive (Annotated)splash10-000i-0900000000-7a5c54ced5b83f291e67Spectrum
MS/MSLC-MS/MS Spectrum - Quattro_QQQ 25V, Positive (Annotated)splash10-0006-0900000000-e6b451ee354ed2717160Spectrum
MS/MSLC-MS/MS Spectrum - Quattro_QQQ 40V, Positive (Annotated)splash10-000i-9500000000-887e5157431b2908f31eSpectrum
MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF (UPLC Q-Tof Premier, Waters) , Positivesplash10-0006-1900000000-06f7059894cc245cb344Spectrum
MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF (UPLC Q-Tof Premier, Waters) , Negativesplash10-0006-0900000000-89a88f44f08b8b68d5c1Spectrum
MS/MSLC-MS/MS Spectrum - LC-ESI-qTof , Positivesplash10-014l-0900000000-3a256522dd8694fe04c0Spectrum
MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , negativesplash10-000f-0900000000-a4b194b85fef656b9b65Spectrum
MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , negativesplash10-0006-0900000000-7862c532805b6036dc67Spectrum
MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , negativesplash10-0006-0900000000-5fe3171fdaece30b78c8Spectrum
MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , negativesplash10-0006-0900000000-df3b5b36289798800ad8Spectrum
MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , negativesplash10-0006-0900000000-d4c11672b9479b2cd4b6Spectrum
MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , negativesplash10-0006-0900000000-89a88f44f08b8b68d5c1Spectrum
MS/MSLC-MS/MS Spectrum - Linear Ion Trap , negativesplash10-0006-0900000000-9c26ffa9c04aa03d60f5Spectrum
MS/MSLC-MS/MS Spectrum - Linear Ion Trap , negativesplash10-0006-0900000000-6a8662ef19d900499a55Spectrum
MS/MSLC-MS/MS Spectrum - , negativesplash10-0006-0900000000-d69a430b0eb34f38ad54Spectrum
MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , positivesplash10-0006-0900000000-d0ef7c769d4985e85667Spectrum
MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , positivesplash10-01ox-0900000000-2a593c8017254be4a387Spectrum
MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , positivesplash10-01ox-0900000000-59f3559c0b95c9411d2cSpectrum
MS/MSLC-MS/MS Spectrum - LC-ESI-QTOF , positivesplash10-02tc-0900000000-57dbbfb8e12c60951d77Spectrum
Predicted MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-0006-0900000000-878dcda0ee5ec971fa72Spectrum
Predicted MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-0006-0900000000-92fe5294ec4a771f14e0Spectrum
Predicted MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0006-1900000000-fa8b36fb6db8e403b711Spectrum
Predicted MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-000i-0900000000-9cede81ef6dfc45f5f7aSpectrum
Predicted MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-000f-0900000000-0d5cf046565b518442d5Spectrum
Predicted MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-0006-2900000000-2c420ff1e59666527005Spectrum
1D NMR1H NMR SpectrumSpectrum
1D NMR1H NMR SpectrumSpectrum
1D NMR1H NMR SpectrumSpectrum
1D NMR13C NMR SpectrumSpectrum
2D NMR[1H,13C] 2D NMR SpectrumSpectrum
ChemSpider ID3712
KEGG Compound IDC01717
Pubchem Compound ID3845
Pubchem Substance IDNot Available
ChEBI ID18344
Phenol-Explorer IDNot Available
DrugBank IDNot Available
CRC / DFC (Dictionary of Food Compounds) IDNot Available
EAFUS IDNot Available
Dr. Duke IDNot Available
BIGG ID38234
KNApSAcK IDNot Available
Food Biomarker OntologyNot Available
VMH IDNot Available
Flavornet IDNot Available
GoodScent IDNot Available
SuperScent IDNot Available
Wikipedia IDKynurenic acid
Phenol-Explorer Metabolite IDNot Available
Duplicate IDSNot Available
Old DFC IDSNot Available
Associated Foods
FoodContent Range AverageReference
Biological Effects and Interactions
Health Effects / BioactivitiesNot Available
NameGene NameUniProt ID
Kynurenine--oxoglutarate transaminase 3CCBL2Q6YP21
Kynurenine--oxoglutarate transaminase 1CCBL1Q16773
Tryptophan MetabolismSMP00063 map00380
MetabolismNot Available
BiosynthesisNot Available
Organoleptic Properties
FlavoursNot Available
Synthesis ReferenceNot Available
General ReferenceNot Available
Content Reference