Life Science Encyclopedia

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.

Pharmacology

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

References

• 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.