Many species have been found to contain betacarboline harmala alkaloids which are MAOIs with anti-depressant properties. The flower and fruit has only traces of these chemicals, but the leaves and the roots are often more potent and have been used to enhance the effects of mind-altering drugs. Once dried, the leaves can also be smoked. Chrysin, a commercially important flavone found in the Blue Passion Flower.
Other interesting compounds found in passion flowers are coumarins (e.g. scopoletin and umbelliferone) and cyanogenic glycosides (e.g. gynocardin) which render some species – e.g. P. adenopoda – somewhat poisonous), maltol and phytosterols (e.g. lutenin). Many flavonoids and their glycosides have been found in Passiflora, including apigenin, homoorientin, 7-isoorientin, isoshaftoside, isovitexin, kaempferol, lucenin, luteolin, n-orientin, passiflorine (named after the genus), quercetin, rutin, saponaretin, saponarin, shaftoside, vicenin and vitexin. Blue Passion Flower (P. caerulea) and perhaps others contain chrysin, a flavone with confirmed anxiolytic and anti-inflammatory, and supposed (though probably in error) 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 against generalized anxiety disorder, Maypop extract performed as well as oxazepam but with less short-term side effects. It was recommended to follow up with long-term studies.
Passion flower also may be effective for anxiety disorder, but further studies are needed