Passionflower

Passiflora incarnata

Family: Passifloraceae Part used: Aerial parts (leaves, stems, flowers)

Key Compounds

• Chrysin
• Vitexin
• Isovitexin
• Orientin
• Isoorientin
• Apigenin
• Luteolin
• Quercetin
• Kaempferol
• Passiflorine
• Harmine
• Harmaline
• Harmol
• Maltol

Traditional Use

• Anxiety — 2001 Akhondzadeh et al. RCT (Journal of Clinical Pharmacy and Therapeutics): 36 patients, passionflower vs oxazepam (benzodiazepine) for generalised anxiety disorder; passionflower was statistically non-inferior for anxiety reduction; oxazepam produced significantly higher impairment of job performance; this is the benchmark comparison study
• Sleep support — traditional and clinical use for sleep difficulty related to anxiety; the GABAergic mechanism supports sleep onset; German Commission E approved for 'nervous restlessness'
• GABA-A modulation — chrysin, the primary flavone, is a positive allosteric modulator of GABA-A receptor (same receptor type as benzodiazepines, but binding a different site with different efficacy); multiple flavones in passionflower may act synergistically on GABA-A
• Native American traditional medicine — Cherokee used *Passiflora incarnata* roots for boils and ears, leaves as poultice; Houma people used root tea as a blood tonic; Natchez used the plant for weaning; anxiety and sleep uses are well-documented across southeastern US tribes
• German Commission E approved — for 'nervous restlessness'; approved for non-prescription anxiolytic use in Germany; used in standardised preparations across Europe
• Antispasmodic — traditional use for smooth muscle spasm; the antispasmodic effect is related to GABAergic activity and direct smooth muscle relaxation; used in European herbal practice for nervous stomach and intestinal cramping

Spanish missionaries arriving in South America in the 16th century looked at this flower and saw the Passion of Christ.

The ten petals and sepals: the ten apostles present at the crucifixion. The corona filaments: the crown of thorns. The five anthers: the five wounds. The three stigmas: the three nails. The vine’s tendrils: the whips.

They named it accordingly. The name is still in use: passio flos — passion flower — after what they believed they had found encoded in the petals.

The flower is genuinely extraordinary. Whether it contains a theological message is a separate question.

Meet the plant

A climbing vine native to the southeastern United States — Virginia south to Florida, west to Texas. It climbs by tendrils to 6–10 metres. Three-lobed leaves. An elaborate, architecturally complex flower unlike anything else in the temperate flora. Yellow-green edible fruit called maypop.

It grows in open habitats, forest margins, fields, and roadsides. It is the hardiest of the cultivable passionflowers and survives frost.

Before the missionaries

The Cherokee used the root for boils and ear infections. The Houma used a root tea as a general tonic. Multiple southeastern US indigenous peoples used the plant for calming and sleep.

This is the baseline use — available, observed, and recorded. The missionaries brought the flower to European attention and named it for theological reasons. The indigenous use came first and described what the plant actually does: calms the nervous system, supports sleep, reduces anxiety. The Christianised naming is an overlay on a pre-existing medical tradition.

European settlers adopted the plant’s calming uses from indigenous contacts. By the 18th and 19th centuries, passionflower was in use as a nervine throughout North America and was introduced to European practice.

The benzodiazepine comparison

In 2001, a clinical trial in Iran (Akhondzadeh et al., Journal of Clinical Pharmacy and Therapeutics) compared passionflower extract directly to oxazepam — a standard prescription benzodiazepine for generalised anxiety disorder.

36 patients were randomly assigned. Both groups took treatment for four weeks. Both groups showed significant anxiety reduction. There was no statistically significant difference in anxiety scores between groups: passionflower was non-inferior to the benzodiazepine.

The significant difference was elsewhere. The oxazepam group had significantly greater impairment of job performance compared to the passionflower group.

This is the study cited when passionflower is described as providing anxiety relief without the sedation that impairs daytime function. It is one trial, relatively small, one specific condition, four weeks. It does not establish passionflower as equivalent to all pharmaceutical anxiolytics. It does establish that for this comparison, the herb performed comparably on anxiety measures and significantly better on functional outcomes.

The GABA-A mechanism

Chrysin (5,7-dihydroxyflavone) — a primary flavone in passionflower — is a positive allosteric modulator of the GABA-A receptor. It binds to the benzodiazepine-sensitive site and increases the receptor’s response to GABA.

This is the same receptor as benzodiazepines. The same binding site. The mechanism is identical in type; the potency is far lower. Pharmaceutical benzodiazepines are full agonists at high potency. Chrysin modulates the receptor at low potency. This difference in potency is why passionflower produces calming without producing the sedation, muscle relaxation, and dependence risk of benzodiazepines.

The passionflower flavone profile is complex: chrysin, vitexin, isovitexin, orientin, isoorientin — multiple compounds with GABA-A activity may act synergistically. The plant also contains trace beta-carboline alkaloids (harmine, harmaline) — weak MAO inhibitors that may contribute additional anxiolytic effect.

What people actually do with it

Tea (most common for mild anxiety/sleep): 1–2 teaspoons dried aerial parts, steeped 10–15 minutes. One cup in the evening for sleep; 2–3 cups daily for anxiety support. Mild, slightly grassy flavour.

Tincture: 1–4 mL, 2–4 times daily. More concentrated and consistent than dried herb.

Standardised extract: 400–900 mg daily. Used in the clinical trial context.

Combined preparations: Passionflower is frequently combined with valerian, lemon balm, or hops in commercial sleep and anxiety formulations. These combinations have clinical trial support — the lemon balm + valerian combination in particular.

For sleep onset specifically: Take 30–60 minutes before bed. The calming effect is most useful for anxiety-related sleep difficulty rather than for people who fall asleep easily but wake at night.

Could you grow this yourself?

In temperate climates with mild winters: yes, and it grows vigorously. Passiflora incarnata is the cold-hardiest passionflower, surviving to -20°C with mulching. It spreads by underground runners and can become invasive in suitable conditions.

In Japanese gardens, トケイソウ is grown for the ornamental flowers — the plant is cultivated as a tender perennial or annual in most of Japan, except Kyushu and Okinawa where it survives winter outdoors.

Harvest aerial parts when the plant is in flower for highest flavone content.

Passionflower (トケイソウ) in Japan

Passionflower is known in Japan primarily as an ornamental plant. The common Japanese name トケイソウ (tokei-sō) means clock flower — the radiating corona filaments resemble clock hands. It is cultivated in gardens and as a potted plant for its spectacular flowers.

The anxiety and sleep indication is present in the Japanese supplement market. Passionflower appears in sleep support formulations marketed under the categories of 睡眠サポート (sleep support) and リラックス (relaxation). The awareness of the GABA-A mechanism appeals to Japanese consumers familiar with the benzodiazepine comparison study.

Japan has no classical traditional medicine relationship with passionflower. The plant is entirely a modern import via ornamental horticulture and supplement commerce.

Things you’re probably wondering

What did the missionaries see? A flower with ten petals/sepals (ten apostles), a corona of filaments (crown of thorns), five anthers (five wounds), three stigmas (three nails). They required some creative counting. The flower is genuinely extraordinary.

How does it compare to benzodiazepines? One 2001 RCT: non-inferior for anxiety reduction, significantly less job-performance impairment. One trial, four weeks, 36 patients. Passionflower is not a pharmaceutical equivalent — it is a lower-potency calming herb.

Is chrysin the active compound? It is the best-studied one. The full picture likely involves multiple flavones acting synergistically at GABA-A, plus trace beta-carboline alkaloids.

Can you eat the fruit? Yes. Maypop — the yellow-green egg-shaped fruit — is sweet and aromatic, eaten fresh or made into juice and jelly.

Botanical details

The full compound list

See Also

• Valerian — complementary GABAergic sedative; commonly combined in sleep formulas
• Lemon Balm — mild anxiolytic with cognitive improvement; combined in anxiety and sleep formulas
• Hops — sedative via MBE and GABA-A; another common sleep-formula partner

References

• Akhondzadeh, S. et al. (2001). Passionflower in the treatment of generalized anxiety. Journal of Clinical Pharmacy and Therapeutics, 26(5), 363–367.
• Miroddi, M. et al. (2013). Passiflora incarnata L.: ethnopharmacology, clinical application, safety and evaluation of clinical trials. Journal of Ethnopharmacology, 150(3), 791–804.
• Appel, K. et al. (2011). Modulation of the γ-aminobutyric acid system by Passiflora incarnata. Phytotherapy Research, 25(6), 838–843.
• Dhawan, K. et al. (2004). Passiflora: a review update. Journal of Ethnopharmacology, 94(1), 1–23.