Foliage experiment

Don't try this at home folks....To experience the above consequences of herbivory I tried chewing a P. caerulea leaf. At first it is quite sweet, then as the cells are crushed the taste and smell changes due to the bitterness caused by the very rapid cyanide release..which results in you spitting it out. It left my tongue feeling a bit odd for a while. The bitter taste is to discourage rather than kill bigger predators, so we are unlikely to come to harm, though the plants hope to do more severe damage to caterpillars. See Defences. Nevertheless assume that all fresh Passiflora foliage is toxic. The foliage of many Passiflora even when undamaged also often has a pungent bitter smell to warn you.

  Fruit

I would recommend only eating ripe fruit from commercial sources like shops and markets. See also Passion fruit. Passion fruit juice is used worldwide in exotic drinks etc. The fruit are also widely available, usually being P. edulis, yellow or purple fruit, or occasionally P. ligularis which has a hard brittle shell. Unripe fruit can also contain poisonous cyanogenic glycosides. P. adenopoda & possibly P. gibertii unripe fruit are of particular concern. There is also a question as to whether P. 'St. Rule' is also P. gibertii under another name. Henk Wouters advises however that the P. gibertii grown from seed from Mauro Peixoto in Brazil, in Piet Moerman's Collection, has bigger flowers, different buds, stronger leaves, etc compared with P. 'St. Rule'. He also thinks the one now named as P. gibertii is possibly P. pallens.

  Toxicity

Dr. John MacDougal comments on the Passiflora list:-

 'I must come down firmly against fooling around casually with the eating the shells or rinds of passifloras. Many are poisonous. Millions of years of God's evolution has made the fruit to be delicious, ...inside!
Maybe when ripe the outside is OK, or if they are bred to be bland, like cultivated P. quadrangularis, but wild species are dangerous to play around with, especially raw. And unripe fruit walls are very very
dangerous! Cut it and smell it-you can often detect the cyanide.
You may have smelled it when you cut a fruit that still had seeds at the "white stage." Most species of passiflora produce cyanide in all their parts as a protection against insects and animals eating them. The young, developing ovary and immature fruit often have the highest concentration of all!!! (to protect the baby seeds?). But not all species have been tested.

In 1972 two children in Costa Rica were poisoned by eating green, immature fruit of P. adenopoda. One kid died. Saenz, J. A. (1972) Toxic effect of fruit of Passiflora adenopoda DC. on humans: Phytochemical determination. Rev Biol Trop 20(1):137-140)

It is NOT just this species, but many, if not Most species that could do this. Just as "peach leaf tea" kills kids in the USA sometimes. Even
ripe fruit has a trace, but not enough to hurt you.

***So, the general rule is: Don't Eat green , Immature, or Developing Fruits, especially raw! When ripe, the pulp of all species is probably OK.

P. quadrangularis rind is apparently OK, but is often candied, cooked,
or blended with other things first.''