beta-Carboline

β-Carboline
IUPAC name

9H-β-carboline
Other names

9H-pyrido[3,4-b]indole
Identifiers
CAS number 244-63-3 Y
PubChem 64961
ChemSpider 58486 Y
MeSH norharman
ChEBI CHEBI:109895 Y
ChEMBL CHEMBL275224 Y
Jmol-3D images Image 1
Properties
Molecular formula C11H8N2
Molar mass 168.20 g/mol
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

β-Carboline (9H-pyrido[3,4-b]indole) also known as norharmane is a nitrogen containing heterocycle. It is also the prototype of a class of compounds known as β-carbolines.

Contents

Pharmacology

β-Carboline alkaloids are widespread in plants and animals, and frequently act as monoamine oxidase inhibitors (MAOI). As components of the liana Banisteriopsis caapi, the β-carbolines harmine, harmaline, and tetrahydroharmine play a pivotal role in the pharmacology of the indigenous hallucinogenic drug ayahuasca by preventing the breakdown of dimethyltryptamine in the gut by inhibiting monoamine oxidase, thus making it psychoactive upon oral administration. Some β-carbolines, notably tryptoline and pinoline, are formed naturally in the human body. The latter is implicated along with melatonin in the role of the pineal gland in regulating the sleep-wake cycle. The β-carboline can link to cerebral benzodiazepine receptors and induce inverse agonist effect.

Structure

β-Carboline belongs to the group of indole alkaloids and consist of pyridine ring that is fused to an indole skeleton.[1] The structure of β-carboline is similar to that of tryptamine, with the ethylamine chain re-connected to the indole ring via an extra carbon atom, to produce a three-ringed structure. The biosynthesis of β-carbolines is believed to follow this route from analogous tryptamines. Different levels of saturation are possible in the third ring, which is indicated here in the structural formula by colouring the optionally double bonds red and blue:

Examples of β-carbolines

Some of the more important β-carbolines are tabulated by structure below.

Short Name
Red Bond
Blue Bond
 R1 R6 R7 Structure
β-Carboline
×
×
H
H
H
Tryptoline    
H
H
H
Pinoline    
H
OCH3
H
Harmane
×
  
CH3
H
H
Harmine
×
×
CH3
H
OCH3
Harmaline
×
  
CH3
H
OCH3
Tetrahydroharmine    
CH3
H
H
OCH3

Occurrence in nature

"There are presently 64 known β-carboline alkaloids dispersed throughout at least eight plant families." The seeds of Peganum harmala (Syrian Rue) are a good source of beta-carbolines, since they contain about 2-6% alkaloids, most of which is harmaline.[2]

As a result of the presence of β-carbolines in the cuticle of scorpions, their skin is known to fluoresce when exposed to certain wavelengths of ultraviolet light such as that produced by a blacklight.[3]

Several β-carbolines have actions opposite to those of benzodiazepines: convulsive, anxiogenic and memory enhancing.[4]

See also

References

  1. ^ The Encyclopedia of Psychoactive Plants: Ethnopharmacology and its Applications. Ratsch, Christian. Park Street Press c. 2005
  2. ^ www.amazing-nature.com
  3. ^ Stachel SJ, Stockwell SA, Van Vranken DL (August 1999). "The fluorescence of scorpions and cataractogenesis". Chem. Biol. 6 (8): 531–9. doi:10.1016/S1074-5521(99)80085-4. PMID 10421760. 
  4. ^ Venault P, Chapouthier G (2007). "From the behavioral pharmacology of beta-carbolines to seizures, anxiety, and memory". ScientificWorldJournal 7: 204–23. doi:10.1100/tsw.2007.48. PMID 17334612. 

External links