Harmaline

Harmaline, also known as 7-methoxyharmalan or as 3,4-dihydro-7-methoxy-1-methyl-β-carboline, is a fluorescent indole alkaloid from the group of harmala alkaloids and β-carbolines. It is the partly hydrogenated form of harmine. It is a reversible monoamine oxidase inhibitor (RIMA). It produces vivid dream-like visual effects and physical discomfort at oral doses of 300 to 400 mg, often leading users to seek solitude in a quiet, dark environment.

Plants containing harmaline are combined in ayahuasca to inhibit monoamine oxidase, allowing orally ingested DMT to remain active in the brain and produce psychoactive effects. Harmala alkaloids, including harmaline, are psychoactive on their own in humans, with harmaline being particularly hallucinogenic, although other compounds such as harmine and tetrahydroharmine have also been reported to produce hallucinogenic effects as well.

Harmaline exhibits weak affinity for 5-HT_2A and 5-HT_2C receptors, partially substitutes for the psychedelic DOM in rodents, inhibits acetylcholinesterase and histamine N-methyltransferase, and stimulates dopamine release at high doses.

Harmaline is present in Peganum harmala (Syrian rue). Syrian rue seeds contain about 3% harmala alkaloids by dry weight. Harmaline was first isolated from plants in 1841, its chemical structure identified in 1919, and it was first synthesized in 1927.