Some indigenous Peruvian people produce a brew which is fascinating from both a chemical and cultural standpoint. As part of a religious ritual, they drink a psychedellic tea (Ayahuasca) produced from a variety of local plants, which could include Banisteriopsis caapi and Psychotria viridis. Several studies have concluded that the ritual use of ayahuasca is not associated with the drawbacks typically caused by drugs of abuse.
The first plant, caapi, has in its stems a class of alkaloids know as β-carbolines. These compounds which include harmine and harmaline act as inhibitors of mitochondrial oxidizing enzymes know as monoamine oxidases (MOA). The inhibitors themselves are abbreviated MOI.
Psychotria viridis contains the psychedelic agent N-N-dimethyltryptamine(DMT), which acts similarly to mescaline in that it activates serotonin receptors in the brain. But DMT is normally deactivated when taken orally. Its amino group is oxidized.
DMT is active only when injected, which is not what Peruvian shamans do. So why does Ayahuasca tea induce hallucinations? Normally DMT is deactivated in the gastrointestinal tract and liver by MOAs. But since the tea also includes the β-carbolines that act as inhibitors of the degradating enzymes, the DMT is free to travel to the brain and induce its effects.
How did past cultures discover this plant-combination and others? It may have involved not only trial and error but keeping a track-record of the attempts and, of course, transmitting the knowledge through generations. The Machiguenga people also use P. viridis as a source of eyedrops, which bypass the digestive tract. In low concentrations, DMT and associated natural products don’t induce hallucinations but help alleviate migraines. Many governments have made DMT illegal, in a situation parallel to other drugs where a compound is purified and stripped not only of its auxiliary natural products but of its cultural context.
Drug synchronicity involving MOIs is not unique. Recently, I came across a blog by Federico Germani (sorry the site has been taken down), who is sensitive to both coffee and chocolate. As he explains, due to genetic variance of a cytochrome enzyme, not everyone is equally efficient at breaking down theobromine, a companion-molecule of caffeine in coffee. Both theobromine and caffeine are MOIs, albeit weak ones, which could explain why he gets unusually euphoric after ingesting chocolate on an empty stomach. Chocolate contains phenylethylamine, which in the presence of MOAs normally gets broken down quickly. But if theobromine, which is also present in chocolate, persists due to his variant cytochrome enzyme, it interferes with phenylethylamine’s breakdown. And when the latter lingers, it boosts production of dopamine in his brain.
For those of you may share my fetish for structural formulas, here are more of the structures discussed above, and keep in mind that I love them more when the compounds are within the confines of living plant tissue. 🙂