Harmine - MAOI and possible inspiration behind In-A-Gadda-Da-Vida

• β-carboline alkaloid found in several species of plants belongings to the families Malpighiaceae and Zygophyllacae AND in butterflies of the family Nymphalidae (how trippy is that? psychedelic butterflies...IRON BUTTERFLY FOR TEH WIN!)
• plants known and exploited for their harmine content include Banisteriopsis caapi (a vine found in South America) and Peganum harmala (Harmal/Syrian Rue, found in the Middle East)
• reversibly inhibits monoamine oxidase (MAO), an enzyme in the brain that breaks down monoamines, resulting in increased levels of these compounds in the brain (and stimulation of the central nervous system)
• monoamines include neurotransmitters (serotonin, dopamine, norepinephrine), hormones (melatonin), and hallucinogenic drugs (tryptamines such as DMT and psilocybin)
• MAO inhibitors (MAOIs) have been used to treat depression since they inhibit the breakdown of serotonin and norepinephrine, two neurotransmitters that have a role in the pathophysiology of clinical depression, suggesting that harmine may have antidepressant effects
• like synthetic MAOIs, harmine can inhibit the breakdown of tyramine, which can lead to a hypertensive emergency
• plants containing harmine are often used in combination with plants containing DMT (see: yage/ayahuasca) or other tryptamine hallucinogens in order to increase their potency/duration of action (since their breakdown is inhibited by the harmine)
• harmine is generally used in this manner, although there are reports of it having hallucinogenic effects on its own
• was/is also known as banisterine in the late 1920s, when it was used to treat postencephalitic parkinsonism (it was the first MAOI to be used in parkinsonism)
  

Sanchez-Ramos JR. Banisterine and Parkinson's disease. Clin Neuropharmacol. 1991 Oct;14(5):391-402.
http://en.wikipedia.org/wiki/Harmine