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Record Information
StatusExpected but not Quantified
Creation Date2012-09-11 17:32:58 UTC
Update Date2019-01-11 19:38:57 UTC
Secondary Accession Numbers
  • HMDB29838
Metabolite Identification
Common NameHarmalol
DescriptionHarmalol is found in fruits. Harmalol is an alkaloid from Passiflora incarnata (maypops). Harmaline is a reversible inhibitor of MAO-A (RIMA). Harmine is a reversible inhibitor of MAO-A (RIMA). It is important to note that unlike synthetic pharmaceutical MAOIs such as phenelzine, harmine is reversible and selective meaning it does not have nearly as high a risk for the "cheese syndrome" caused by consuming tyramine-containing foods, which is a risk associated with monoamine oxidase A inhibitors, but not monoamine oxidase B inhibitors. Several alkaloids that function as monoamine oxidase inhibitors (MAOIs) are found in the seeds of Peganum harmala (also known as Harmal or Syrian Rue), including harmine, harmaline, and harmalol, which are members of a group of substances with a similar chemical structure collectively known as harmala alkaloids. These alkaloids are of interest for their use in Amazonian shamanism, where they are derived from other plants. The harmala alkaloid harmine which was once known as Telepathine and Banisterine is a naturally occurring beta-carboline alkaloid that is structurally related to harmaline, and also found in the vine Banisteriopsis caapi. Tetrahydroharmine is also found in B. caapi, but not P. harmala. Dr. Alexander Shulgin has suggesed that harmaline may be a breakdown product of harmine. Harmine and harmaline are reversible MAOIs of the MAO-A isoform of the enzyme, and can stimulate the central nervous system by inhibiting the metabolism of monoamine compounds such as serotonin and norepinephrine. The harmala alkaloids occur in Peganum harmala in concentrations of roughly 3%, though tests have documented anywhere from 2-7%, as natural sources tend to vary widely in chemical makeup. Harmala alkaloids are also found in the Banisteriopsis caapi vine, the key plant ingredient in the sacramental beverage Ayahuasca, in concentrations that range between 0.31-8.43% for harmine, 0.03-0.83% for harmaline and 0.05-2.94% for tetrahydroharmine. Other psychoactive plants are often added to Ayahuasca to achieve visionary states of consciousness; for example leaves from Psychotria viridis, which is a source of dimethyltryptamine (DMT). The harmala alkaloids serve to potentiate these brewed compounds by preventing their breakdown in the digestive tract. The harmala alkaloids are not especially psychoactive on their own, even at high dosages, when vomiting and diarrhea become the main effect
1-Methyl-4,9-dihydro-3H-beta-carbolin-7-ol hydrochlorideHMDB
4,9-dihydro-1-Methyl-3H-pyrido[3,4-b]indol-7-ol, 9ciHMDB
Chemical FormulaC12H12N2O
Average Molecular Weight200.2365
Monoisotopic Molecular Weight200.094963016
IUPAC Name1-methyl-3H,4H,9H-pyrido[3,4-b]indol-7-ol
Traditional Nameharmalol
CAS Registry Number525-57-5
InChI Identifier
Chemical Taxonomy
DescriptionThis compound belongs to the class of organic compounds known as harmala alkaloids. These are compounds with a structure based on harmaline, harmine, harmalol, harman or a derivative of those parents. These parents are beta-carbolines, consisting of a pyrimidine fused to the pyrrole moiety of an indole to form a pyrido[3,4-b]indole.
KingdomOrganic compounds
Super ClassAlkaloids and derivatives
ClassHarmala alkaloids
Sub ClassNot Available
Direct ParentHarmala alkaloids
Alternative Parents
  • Harmalol
  • Harmaline
  • Harman
  • Pyridoindole
  • Beta-carboline
  • Hydroxyindole
  • Indole or derivatives
  • Indole
  • Benzenoid
  • Heteroaromatic compound
  • Pyrrole
  • Ketimine
  • Azacycle
  • Organoheterocyclic compound
  • Organic 1,3-dipolar compound
  • Propargyl-type 1,3-dipolar organic compound
  • Hydrocarbon derivative
  • Organooxygen compound
  • Organonitrogen compound
  • Imine
  • Aromatic heteropolycyclic compound
Molecular FrameworkAromatic heteropolycyclic compounds
External Descriptors

Route of exposure:


Biological location:

Physical Properties
Experimental Properties
Melting Point100 - 105 °CNot Available
Boiling PointNot AvailableNot Available
Water SolubilityNot AvailableNot Available
LogP2.19Not Available
Predicted Properties
Water Solubility0.2 g/LALOGPS
pKa (Strongest Acidic)9.61ChemAxon
pKa (Strongest Basic)6.31ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count2ChemAxon
Hydrogen Donor Count2ChemAxon
Polar Surface Area48.38 ŲChemAxon
Rotatable Bond Count0ChemAxon
Refractivity59.67 m³·mol⁻¹ChemAxon
Polarizability22.08 ųChemAxon
Number of Rings3ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectrum TypeDescriptionSplash Key
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positivesplash10-05fr-0900000000-e4464398b4dec3fc7352View in MoNA
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (1 TMS) - 70eV, Positivesplash10-00di-7190000000-1284b3e28670778298feView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-0udi-0290000000-a117734dd274e28b35adView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-0udi-1970000000-b19698ef3a7ac01eec3fView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0a4l-0900000000-f10b93cb6c00a71896feView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-0002-0900000000-aaba7e72d490321c1aa2View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-0002-0900000000-78586bb5e1894bd774f1View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-00lr-2900000000-fd7e4b643b65563440d4View in MoNA
Biological Properties
Cellular Locations
  • Cytoplasm
  • Extracellular
Biospecimen LocationsNot Available
Tissue LocationsNot Available
Normal Concentrations
Not Available
Abnormal Concentrations
Not Available
Associated Disorders and Diseases
Disease ReferencesNone
Associated OMIM IDsNone
DrugBank IDNot Available
Phenol Explorer Compound IDNot Available
FoodDB IDFDB001053
KNApSAcK IDNot Available
Chemspider ID11262879
KEGG Compound IDC06537
BioCyc IDCPD-9938
BiGG IDNot Available
Wikipedia LinkHarmalol
METLIN IDNot Available
PubChem CompoundNot Available
PDB IDNot Available
ChEBI ID27943
Synthesis ReferenceNot Available
Material Safety Data Sheet (MSDS)Not Available
General References
  1. (). Yannai, Shmuel. (2004) Dictionary of food compounds with CD-ROM: Additives, flavors, and ingredients. Boca Raton: Chapman & Hall/CRC.. .