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IUPAC name
Other names
Harman, Aribine, Aribin, Locuturine, Locuturin, Loturine, Passiflorin, 1-Methylnorharman, NSC 54439
3D model (JSmol)
ECHA InfoCard 100.006.948
EC Number 207-642-2
Molar mass 182.226 g·mol−1
Melting point 235–238 °C (455–460 °F; 508–511 K)
Soluble to 10 mM in 1 eq. HCl[1]

methanol: soluble 50 mg/ml

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Harmane (harman) is a heterocyclic amine found in a variety of foods including coffee,[2] sauces,[3] and cooked meat.[4] It is also present in tobacco smoke.[5]


Harmane is a methylated derivative of β-carboline with the molecular formula C12H10N2.

Biological effects[edit]

Harmane is a potent reversible inhibitor of monoamine oxidase A (RIMA)[2][6][7] and acts as a moderate affinity inverse agonist at the benzodiazepine site of the GABA-A receptor.[8] Harmane has been suggested as a potential candidate (or component thereof) for the endogeneous ligand of imidazoline receptor, although the evidence is limited and equivocal.[9][10][11]

In the rat, harmane damages certain dopaminergic dendritic arbors at sufficiently high doses.[12] Blood levels of harmane and similar beta-carbolines are associated with essential tremor and Parkinson's disease.[13]

See also[edit]


  1. ^ "Harmane". tocris.com.
  2. ^ a b Herraiz, T; Chaparro, C (2006). "Human monoamine oxidase enzyme inhibition by coffee and beta-carbolines norharman and harman isolated from coffee". Life Sciences. 78 (8): 795–802. doi:10.1016/j.lfs.2005.05.074. PMID 16139309.
  3. ^ Herraiz, T. (2004). "Relative exposure toβ-carbolines norharman and harman from foods and tobacco smoke". Food Additives and Contaminants. 21 (11): 1041–50. doi:10.1080/02652030400019844. PMID 15764332.
  4. ^ Louis, E. D.; Zheng, W; Jiang, W; Bogen, K. T.; Keating, G. A. (2007). "Quantification of the neurotoxic beta-carboline harmane in barbecued/grilled meat samples and correlation with level of doneness". Journal of Toxicology and Environmental Health, Part A. 70 (12): 1014–9. doi:10.1080/15287390601172015. PMC 4993204. PMID 17497412.
  5. ^ Herraiz, Tomas; Chaparro, Carolina (2005). "Human monoamine oxidase is inhibited by tobacco smoke: β-carboline alkaloids act as potent and reversible inhibitors". Biochemical and Biophysical Research Communications. 326 (2): 378. doi:10.1016/j.bbrc.2004.11.033. PMID 15582589.
  6. ^ Rommelspacher, H; May, T; Salewski, B (1994). "Harman (1-methyl-beta-carboline) is a natural inhibitor of monoamine oxidase type a in rats". European Journal of Pharmacology. 252 (1): 51–9. doi:10.1016/0014-2999(94)90574-6. PMID 8149995.
  7. ^ Adell, A; Biggs, T. A.; Myers, R. D. (1996). "Action of harman (1-methyl-beta-carboline) on the brain: Body temperature and in vivo efflux of 5-HT from hippocampus of the rat". Neuropharmacology. 35 (8): 1101–7. doi:10.1016/s0028-3908(96)00043-3. PMID 9121613.
  8. ^ Rommelspacher, H; Nanz, C; Borbe, H. O.; Fehske, K. J.; Müller, W. E.; Wollert, U (1980). "1-Methyl-beta-carboline (harmane), a potent endogenous inhibitor of benzodiazepine receptor binding". Naunyn-Schmiedeberg's Archives of Pharmacology. 314 (1): 97–100. doi:10.1007/bf00498436. PMID 6255348.
  9. ^ Abu Ghazaleh, Haya; Lalies, Maggie D.; Nutt, David J.; Hudson, Alan L. (2015-03-17). "Harmane: an atypical neurotransmitter?". Neuroscience Letters. 590: 1–5. doi:10.1016/j.neulet.2015.01.057. ISSN 1872-7972. PMID 25625221.
  10. ^ Smith, Karen L.; Ford, Gemma K.; Jessop, David S.; Finn, David P. (February 2013). "Behavioural, neurochemical and neuroendocrine effects of the endogenous β-carboline harmane in fear-conditioned rats". Journal of Psychopharmacology (Oxford, England). 27 (2): 162–170. doi:10.1177/0269881112460108. ISSN 1461-7285. PMID 23015542.
  11. ^ Anderson, Neil J.; Tyacke, Robin J.; Husbands, Stephen M.; Nutt, David J.; Hudson, Alan L.; Robinson, Emma S. J. (March 2006). "In vitro and ex vivo distribution of [3H]harmane, an endogenous beta-carboline, in rat brain". Neuropharmacology. 50 (3): 269–276. doi:10.1016/j.neuropharm.2005.08.022. ISSN 0028-3908. PMID 16242163.
  12. ^ Celikyurt, I. K.; Utkan, T; Gocmez, S. S.; Hudson, A; Aricioglu, F (2013). "Effect of harmane, an endogenous β-carboline, on learning and memory in rats". Pharmacology Biochemistry and Behavior. 103 (3): 666–71. doi:10.1016/j.pbb.2012.10.011. PMID 23107644.
  13. ^ Louis, E. D.; Zheng, W; Jurewicz, E. C.; Watner, D; Chen, J; Factor–Litvak, P; Parides, M (2002). "Elevation of blood β-carboline alkaloids in essential tremor". Neurology. 59 (12): 1940–1944. doi:10.1212/01.wnl.0000038385.60538.19. PMC 4992345. PMID 12499487.