Tetrahydroharmine (THH) is a

fluorescent Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, tha ...

indole alkaloid Indole alkaloids are a class of alkaloids containing a structural moiety of indole; many indole alkaloids also include isoprene groups and are thus called terpene indole or secologanin tryptamine alkaloids. Containing more than 4100 known differe ...

that occurs in the tropical

liana A liana is a long- stemmed, woody vine that is rooted in the soil at ground level and uses trees, as well as other means of vertical support, to climb up to the canopy in search of direct sunlight. The word ''liana'' does not refer to a ta ...

species ''

Banisteriopsis caapi ''Banisteriopsis caapi'', also known as ayahuasca, caapi, soul vine, or yagé (yage), is a South American liana of the family Malpighiaceae. It is one half of ayahuasca, a decoction with a long history of its entheogenic (connecting to spirit) us ...

''. THH, like other

harmala alkaloid Several alkaloids that function as monoamine oxidase inhibitors (MAOIs) are found in the seeds of ''Peganum harmala'' (also known as ''Harmal'' or ''Syrian Rue''), as well as tobacco leaves including harmine, harmaline, and harmalol, which are m ...

s in ''B. caapi'', namely

harmaline Harmaline is a fluorescent indole alkaloid from the group of harmala alkaloids and beta-carbolines. It is the partly hydrogenated form of harmine. Occurrence in nature Various plants contain harmaline including ''Peganum harmala'' (Syrian rue) ...

and

harmine Harmine is a beta-carboline and a harmala alkaloid. It occurs in a number of different plants, most notably the Syrian rue and ''Banisteriopsis caapi''. Harmine reversibly inhibits monoamine oxidase A (MAO-A), an enzyme which breaks down monoamin ...

, is a

reversible inhibitor of monoamine oxidase A Monoamine oxidase inhibitors (MAOIs) are a class of drugs that inhibit the activity of one or both monoamine oxidase enzymes: monoamine oxidase A (MAO-A) and monoamine oxidase B (MAO-B). They are best known as effective antidepressants, especia ...

(RIMA), but it also inhibits the

reuptake Reuptake is the reabsorption of a neurotransmitter by a neurotransmitter transporter located along the plasma membrane of an axon terminal (i.e., the pre-synaptic neuron at a synapse) or glial cell after it has performed its function of transm ...

serotonin Serotonin () or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Its biological function is complex and multifaceted, modulating mood, cognition, reward, learning, memory, and numerous physiological processes such as vomiting and vas ...

. THH contributes to ''B. caapis psychoactivity as a

serotonin reuptake inhibitor A serotonin reuptake inhibitor (SRI) is a type of drug which acts as a reuptake inhibitor of the neurotransmitter serotonin (5-hydroxytryptamine, or 5-HT) by blocking the action of the serotonin transporter (SERT). This in turn leads to increase ...

Legal Status

Australia

Harmala alkaloids are considered Schedule 9 prohibited substances under the Poisons Standard (October 2015). A Schedule 9 substance is a substance which may be abused or misused, the manufacture, possession, sale or use of which should be prohibited by law except when required for medical or scientific research, or for analytical, teaching or training purposes with approval of Commonwealth and/or State or Territory Health Authorities.

Legal Status

Australia

See also

References

Further reading