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IUPAC name 1,2,3,4-Tetrahydro-9H-pyrido[3,4-b]indole
Other names Noreleagnine
CAS number 16502-01-5
PubChem 107838
Molecular formula C11H12N2
Molar mass 172.226 g/mol
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Tryptoline is a natural organic amine. It is an alkaloid chemically related to tryptamines. Derivatives of tryptoline have a variety of pharmacological properties and are known collectively as tryptolines.


Many tryptolines are competitive selective inhibitors of monoamine oxidase type A (MAO-A). 5-Hydroxytryptoline and 5-methoxytryptoline are the most active monoamine oxidase inhibitors with IC50s of 0.5 μM and 1.5 μM respectively, using 5-hydroxytryptamine as substrate.

Tryptolines are also potent reuptake inhibitors of 5-hydroxytryptamine and epinephrine; a significantly greater uptake inhibitory selectivity being shown for 5-hydroxytryptamine than epinephrine. The comparison of the inhibition kinetics of tetrahydro-β-carbolines for 5-hydroxytryptamine and epinephrine uptake (with that of the platelet aggregation response to these amines) have shown that 5-hydroxymethtryptoline, methtryptoline, and tryptoline are poor inhibitors of uptake. In all respects 5-hydroxytryptoline and 5-methoxytryptoline showed greater pharmacological activity than the tryptoline and methtryptoline.

Although the in vivo formation of tryptolines has been a matter of controversy, they have profound pharmacological activity.

See also

  • beta-Carboline
  • Harmala alkaloid


  • H. Rommelspacher, H. Kauffmann, C. Heyck Cohnitz and H. Coper (1977). "Pharmacological properties of tetrahydronorharmane (Tryptoline)". Journal Naunyn-Schmiedeberg's Archives of Pharmacology 298 (2): 83-91. doi:10.1007/BF00508615 DOI 10.1007/BF00508615.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Tryptoline". A list of authors is available in Wikipedia.
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