Passionflower: Background. Actions

2010

Common Name

Passionflower

Other Names

Apricot vine, granadilla, Jamaican honeysuckle, Maypop passion flower, passion vine, water lemon

Botanical Name / Family

Passiflora incarnata (family Passifloraceae)

Plant Parts Used

Aerial parts, particularly leaves

Chemical Components

Flavonoids (including apigenin, quercetin and kaempferol), maltol, coumarin derivatives, indole alkaloids (mainly harman, harmaline, harmine), phytosterols (stigmasterol), sugars and small amounts of essential oil.

HARMAN

Numerous in vitro and in vivo trials have been conducted on the constituent known as harman. Some of these studies have suggested:

• mild monoamine oxidase A inhibition

• inhibition of HIV replication

• vasorelaxant activity

• effects on GABA release

Harman is not considered to be one of the main active constituents in the herb and is not present in biologically active concentrations in the dosage range used for passionflower. As such, results obtained using isolated harman in vitro and in vivo cannot necessarily be extrapolated to the use of passionflower in humans.

Harman has also been identified in beer, and to a lesser extent in wine, both of which contain levels far in excess of those found in passionflower at therapeutic doses.

Historical Note

Legend has it that this herb received its name because the corona resembles the crown of thorns worn by Christ during the crucifixion. A popular sedative medicine in the early 20th century, it was listed in the United States National Formulary until 1936.

Passionflower: Main Actions

ANXIOLYTIC AND SEDATIVE ACTIVITY

Several in vivo studies have demonstrated the anxiolytic effects of Passiflora extract. Behavioural tests in mice have also demonstrated that high doses have a sedative effect.

The mechanism of action is currently unclear, as some research suggests stimulation of GABA release or an interaction with GABA receptors, and other research observes no interaction with GABA-benzodiazepine receptors. One in vitro study also showed inhibition of GABA-A binding with Passiflora extract.