Also Known As: Passiflora, Passion flower
Passiflora, known also as the passion flowers or passion vines, is a genus of about 500 species of flowering plants, the namesakes of the family Passifloraceae. They are mostly vines, with some being shrubs, and a few species being herbaceous. For information about the fruit of the passiflora plant, see passionfruit. The monotypic genus Hollrungia seems to be inseparable from Passiflora, but further study is needed.
P. incarnata (maypop) leaves and roots have a long history of use among Native Americans in North America and were adapted by the European colonists. The fresh or dried leaves of maypop are used to make a tea that is used to treat insomnia, hysteria, and epilepsy, and is also valued for its analgesic properties. P. edulis (passion fruit) and a few other species are used in Central and South America for similar purposes. Once dried, the leaves can also be smoked.
Many species have been found to contain beta-carboline harmala alkaloids, which are MAO inhibitors with anti-depressant properties. The flower and fruit have only traces of these chemicals, but the leaves and the roots are often more potent and have been used to potentiate the effects of mind-altering drugs. The most common of these alkaloids is harman (1-methyl-9H-b-carboline), but harmaline (4,9-Dihydro-7-methoxy-1-methyl-3H-pyrido[3,4-b]indole), harmalol (1-methyl-2,3,4,9-tetrahydropyrido[3,4-b]indol-7-one), harmine (7-Methoxy-1-methyl-9H-pyrido[3,4-b]indole) and harmol[clarification needed] were found. The species known to bear such alkaloids include: P. actinea, P. alata (winged-stem passion flower), P. alba, P. bryonioides (cupped passion flower), P. caerulea (blue passion flower), P. capsularis, P. decaisneana, P. edulis (passion fruit), P. eichleriana, P. foetida (stinking passion flower), P. incarnata (maypop), P. quadrangularis (giant granadilla), P. ruberosa, P. subpeltata and P. warmingii.
Other compounds found in passion flowers are coumarins (e.g. scopoletin and umbelliferone), maltol, phytosterols (e.g. lutenin) and cyanogenic glycosides (e.g. gynocardin) which render some species, i.e. P. adenopoda, somewhat poisonous. Many flavonoids and their glycosides have been found in Passiflora, including apigenin, benzoflavone[disambiguation needed ], homoorientin, 7-isoorientin, isoshaftoside, isovitexin (or saponaretin), kaempferol, lucenin, luteolin, n-orientin, passiflorine (named after the genus), quercetin, rutin, saponarin, shaftoside, vicenin and vitexin. Maypop, Blue Passion Flower (P. caerulea), and perhaps others contain chrysin, a flavone with confirmed anxiolytic and anti-inflammatory, supposed aromatase inhibitor properties. Also documented to occur at least in some Passiflora in quantity are the hydrocarbon nonacosane and the anthocyanidin pelargonidin-3-diglycoside.
As regards organic acids, the genus is rich in formic, butyric, linoleic, linolenic, malic, myristic, oleic and palmitic acids as well as phenolic compounds, and the amino acid α-alanine. Esters like ethyl butyrate, ethyl caproate, n-hexyl butyrate and n-hexyl caproate give the fruits their flavor and appetizing smell. Sugars, contained mainly in the fruit, are most significantly d-fructose, d-glucose and raffinose. Among enzymes, Passiflora was found to be rich in catalase, pectin methylesterase and phenolase.
The medical utility of very few species of Passiflora has been scientifically studied. In initial trials for treatment of generalized anxiety disorder, maypop extract performed as well as oxazepam but with fewer short-term side effects. It was recommended to follow up with long-term studies. In another study performed on mice, it was shown that Passiflora alata has a genotoxic effect on cells, and further research was recommended before this one species is considered safe for human consumption.
Passionflower herb (Passiflorae herba) from P. incarnata is official in the European Pharmacopoeia. The herbal drug should contain not less than 1.5% total flavonoids expressed as vitexin. It is used in sedative tea mixtures with other calming herbs.