Passiflora incarnata (Passion Flower) is a flowering vine with a long history of medicinal and entheogenic use. Its name is derived from concepts of Christian theology, related to Jesus and his crucifixion. It is well known for its use in conditions of the nervous system, particularly depression, insomnia and anxiety disorders. Passiflora is also indicated for heart palpitations and epilepsy, usually in combination with other herbs.
Generally the plant is consumed as either an alcohol extract or an infusion (tea), for which the best preparation is two teaspoons per cup of hot water steeped, covered, for several minutes. The herb induces a feeling of peace and tranquility. These effects are thought to be provoked by specific constituents in the vine’s leaves and flowers, which are the parts that contain the highest concentration of active phytochemicals.
Passion Flower contains a complex mixture of active constituents, including low levels of the compounds known as harmala alkaloids. Harmine, one harmala alkaloid, is also found in other plants such as Syrian Rue (Peganum harmala), and the Banisteriopsis caapi vine from South America. Interestingly, harmine has also been found in several species of butterfly.
Harmine and related alkaloids (harmaline, harmalol, etc.) are known to be MAO-inhibitors; MAO is an enzyme that breaks down neurotransmitters like serotonin and dopamine, certain kinds of drugs, and hormones such as melatonin and norepinephrine. Inhibiting the breakdown of these endogenous chemicals helps them to remain active longer in the synapses of the nerves. MAO-inhibiting medications have been used as anti-depressant agents. Unlike conventional pharmaceutical MAO inhibitors, harmine inhibits only MAO-A, without inhibiting MAO-B; thus it has been thought to possibly be a safer alternative.
In addition to the harmala alkaloids, Passiflora contains flavonoids such as apigenin, luteolin, chrysin, and a related compound called BZF that have been found to contribute synergistically to its anti-anxiety effects. This herb has also been found to contain significant levels of GABA, as well as possibly having as-yet unidentified constituents that interact with GABA receptors. Researchers continue to debate the contributions of these different constituents to the observed effects of the herb.
Because Passion Flower contains these interesting phytochemicals, it is both very useful, but also has the potential for interactions when used in combination with certain drugs. If taken with drugs such as sleeping pills and anxiety medications of the benzodiazepine class, or barbiturates like hexobarbital, Passiflora could potentially cause increased sleeping time and sedation, and in some cases overdose. Drugs such as these and others like certain antihistamines, antidepressants and pain medicines should generally not be combined with Passion Flower.