Every herbalist has favourites — herbs they reach for daily with particular kinds of patients, herbs they have a personal relationship with, or simply herbs that are generally magnificent.
Passionflower (Passiflora incarnata) is one I have a great deal of time for. Beyond its sleep-inducing properties, this enchanting plant has so many other uses that it becomes invaluable in clinical practice.
We'll come to those uses, along with its chemistry and some evidence for how it works. First, some background.
A passionate history
Passionflower is native to North and South America, and reached Europe when Spanish conquistadors brought it back from Peru.
They had learned from the Aztecs that the plant served as a sedative for nervousness and insomnia. It entered European medicine and was cultivated widely.
The name — flor de la passion — came from religious symbolism they imagined in the flower, which they said represented the crucifixion of Jesus Christ, the close of the period of his life known as The Passion.
The plant's intricate beauty speaks to modern herbalists rather differently, of course, and has far more to do with its interesting chemical composition and powerful medicinal actions.
What's in a plant?
Looking at it, it is no surprise that passionflower contains hallucinogenic compounds — the indole alkaloids, though commercial preparations carry fewer of these constituents.
Harmine, an indole alkaloid originally called "telepathine",¹ induces a contemplative state and mild euphoria, presumed to act through serotonin receptors.
Researchers disagree over whether passionflower's sedative effects come from those indole alkaloids or from its rich flavonoid content — apigenin, scopoletin and chrysin, the last of which has been shown to bind benzodiazepine receptors.²
Passiflora is also reported to contain more of the calming neurotransmitter gamma-aminobutyric acid (GABA) than 20 other plants examined.³
Passionflower in action
I picture a "passionflower person" as someone wound up — tense, anxious, unable to settle enough to get good, nourishing sleep.
Several clinical studies confirm this calming effect on the nervous system. In a randomised controlled trial of 36 patients over four weeks, passionflower proved as effective as oxazepam, an anti-anxiety drug, with fewer side effects.⁴
Another trial measured self-reported improvements in stress resistance and quality of life among 154 adults with nervous restlessness.⁵ The 12-week results were significant, and associated symptoms — sleep disturbance, fatigue, nausea, palpitations — all improved.
A study of the plant's sleep effects produced similarly good results: drinking passionflower tea gave short-term subjective sleep benefits to 41 healthy adults with mild fluctuations in sleep quality, over seven days.⁶
Something for everyone
Children with attention deficit hyperactivity disorder (ADHD) can benefit enormously from this plant, as can some people with high blood pressure or a fast or irregular heart rhythm.
It has also shown promising results in opiate addiction, helping ease the psychological symptoms of withdrawal.
Quite an amazing plant.
References
Cited by the original article:
Djamshidian A, Bernschneider-Reif S, Poewe W, Lees AJ. Banisteriopsis caapi, a Forgotten Potential Therapy for Parkinson's Disease? Mov Disord Clin Pract. 2015;3(1):19–26.
Brown E, Hurd NS, McCall S, Ceremuga TE. Evaluation of the anxiolytic effects of chrysin, a Passiflora incarnata extract, in the laboratory rat. AANA J. 2007;75(5):333-7.
Carratù B, Boniglia C, Giammarioli S, Mosca M, Sanzini E. (2008) Free Amino Acids in Botanicals and Botanical Preparations. Journal of Food Science, 73:C323-C328.
Akhondzadeh S, Naghavi HR, Vazirian M, Shayeganpour A, Rashidi H, Khani M. Passionflower in the treatment of generalized anxiety: a pilot double-blind randomized controlled trial with oxazepam. J Clin Pharm Ther. 2001;26(5):363-7.
Gibbert J, Kreimendahl F, Lebert J, Rychlik R, Trompetter I. Improvement of Stress Resistance and Quality of Life of Adults with Nervous Restlessness after Treatment with a Passion Flower Dry Extract. Complement Med Res. 2017;24:83-89.
Ngan A, Conduit R. A double-blind, placebo-controlled investigation of the effects of Passiflora incarnata (passionflower) herbal tea on subjective sleep quality. Phytother Res. 2011;25(8):1153-9.
