Passion Flower

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Health Goals: sleep anxiety stress

Research Overview

Across the studies reviewed here, passion flower (Passiflora spp.) research clusters into three main areas: (1) mechanistic and preclinical pharmacology of specific constituents found in some Passiflora species—especially the flavonoid chrysin (reported in blue passion flower) and vitexin (noted as a key ingredient in P. incarnata extracts); (2) neuropsychiatric/sleep applications, including use in mild depression/anxiety (often in combination products) and insomnia-related outcomes; and (3) real-world patterns of complementary and alternative medicine (CAM) use, including passion flower use in pediatric headache cohorts and concerns about concurrent use with prescription medicines in older adults. Much of the mechanistic work is conducted in vitro or in animal models, focusing on inflammatory signaling (e.g., mast cell activation, cytokine expression) and cardiometabolic pathways (e.g., oxidative stress, inflammatory gene expression, gut microbiota changes) rather than on clinical endpoints in humans.

The strongest evidence within these studies supports biological plausibility in preclinical systems rather than definitive clinical efficacy. Chrysin shows relatively consistent anti-allergic/anti-inflammatory activity in mast cell-based models, including inhibition of histamine release and downregulation of pro-inflammatory cytokines via pathways involving intracellular calcium modulation and NF-κB/caspase-1 signaling; in these models it outperformed cromolyn. Separately, in a rat model of diet-induced hypercholesterolemia/atherosclerosis, chrysin improved lipid/oxidative stress markers and altered inflammatory gene expression and gut microbial measures, with effects compared against atorvastatin—suggesting potential cardiometabolic relevance, though still limited to animal data. For neuropsychiatric indications, one study indicates Passiflora extract can potentiate Hypericum (St. John’s wort) in antidepressant screening models (serotonin uptake and forced swim test), and another frames vitexin-containing P. incarnata extract as a candidate for insomnia-related cognitive effects via hippocampal neurogenesis in a sleep-disordered mouse strain; however, these are not substitutes for controlled human trials.

Key gaps are the relative scarcity of rigorous, well-powered human clinical studies using standardized passion flower preparations with defined phytochemical profiles (e.g., quantified vitexin/chrysin and other actives), clear dosing, and validated clinical outcomes for anxiety, insomnia, allergic disease, and cardiometabolic risk. Additional needs include pharmacokinetic and bioavailability studies for candidate constituents, head-to-head comparisons with standard therapies, and systematic safety assessments—particularly drug–herb interaction risk in populations prone to polypharmacy (older adults) and in pediatric use where CAM is common and often undisclosed to clinicians. Overall, the studies suggest promising mechanistic signals and widespread real-world use, but the evidence base remains strongest for preclinical mechanisms and weakest for definitive clinical effectiveness and safety in routine care.

1. What conditions has Passion Flower been studied for?

  • Anxiety / anxiolytic effects: Animal behavioral testing of Passiflora incarnata fractions in the elevated plus-maze (EPM) model.

  • Depression (as an adjunct): Combination of Passiflora with Hypericum (St. John’s wort) assessed in antidepressant-related models (serotonin uptake and forced-swim test).

  • Sleep/insomnia-related outcomes and cognition: Repeated oral administration of Passiflora incarnata extract (with vitexin highlighted as a key component) studied in sleep-disturbed mice, with outcomes including neurogenesis and memory.

  • Memory/learning and Alzheimer’s-related markers: In animals, passion flower extract was studied for effects on hippocampal neurogenesis, water maze performance, and tau phosphorylation (pTau/Tau).

  • Menopausal transition symptoms: A combined nutraceutical containing passion flower plus other ingredients studied for hot flushes, insomnia, fatigue, irritability (Kuppermann Index).

  • Allergic inflammatory reactions (via a passion-flower constituent): Chrysin (noted as present in blue passion flower) studied in mast cell-based in vitro and in vivo models of allergic inflammation/anaphylaxis.

  • Hypercholesterolemia/atherosclerosis (via a passion-flower constituent): Chrysin studied in high-fat diet rat model for lipid profile, oxidative stress, inflammatory gene expression, and gut microbiota changes.

  • Real-world use (not efficacy): Surveys describe passion flower as one of several herbal remedies used in pediatric headache populations (observational use patterns, not a treatment trial).

2. Does it work in treating those conditions? Summarize the evidence.

  • Anxiety: In mice, certain fractions of Passiflora incarnata increased open-arm entries in the EPM (an anxiolytic-like signal). The chloroform fraction showed the strongest effect at very low doses (0.17–0.34 mg/kg), and the butanol fraction also showed activity; the petroleum ether fraction did not. The study reports no change in total distance traveled, arguing against simple sedation/stimulation as the explanation. Limitation: animal model only; fractions are not the same as typical commercial extracts.

  • Depression (adjunct with Hypericum): In two preclinical models (synaptic serotonin uptake and forced-swim test), adding Passiflora enhanced the pharmacological potency of Hypericum, suggesting similar effects might be achievable with lower Hypericum doses when combined. Limitation: preclinical models; not a human clinical trial and not evidence for passion flower monotherapy.

  • Sleep-related outcomes and memory: In sleep-disordered DBA/2 mice, repeated oral administration of passion flower extract (vitexin emphasized) increased hippocampal neurogenesis markers (e.g., DCX) and BDNF, and improved water maze performance (memory). pTau/Tau decreased in both rats and mice after repeated administration. Limitations: animal studies; inflammation markers were “inconsistent” between groups; the mechanistic role of COX-2 signaling appeared complex (COX-2 inhibition affected neurogenesis signals), and translation to humans is uncertain.

  • Menopausal symptoms: A pilot randomized study of a combined nutraceutical (containing phytoestrogens, vitamins/micronutrients, and passion flower) found significant reductions in overall symptom scores and improvements in hot flushes, insomnia, fatigue, and irritability after 3 and 6 months. Limitation: passion flower was one component of a multi-ingredient product, so the specific contribution of passion flower cannot be isolated.

  • Allergic inflammation (chrysin): Chrysin inhibited systemic hypersensitivity and serum histamine release, attenuated IgE-mediated local anaphylaxis, reduced mast-cell histamine release via intracellular calcium modulation, and decreased pro-inflammatory cytokine gene expression (TNF-α, IL-1β, IL-4, IL-6) via NF-κB and caspase-1 dependent pathways. Limitation: this is evidence for a constituent (chrysin) in experimental models, not necessarily for typical passion flower preparations in humans.

  • Hypercholesterolemia/atherosclerosis (chrysin): In high-fat diet rats, chrysin (100 mg/kg) improved lipid profile and oxidative stress markers, altered Nrf2-related gene expression in intestine/aorta, increased certain gut microbial copy numbers, and modulated inflammatory genes (e.g., TLR4, TNFα, NLRP3, IL-17). Limitation: animal model; high dose; not direct evidence that dietary passion flower products produce similar effects in humans.

3. What health benefits does it have?

  • Anxiolytic-like effects (preclinical): Specific Passiflora incarnata fractions increased open-arm exploration in the EPM without changing locomotion, consistent with anxiolytic-like activity in mice.

  • Potential sleep/cognition support (preclinical): Repeated passion flower extract administration increased hippocampal neurogenesis markers and BDNF and improved memory performance in a sleep-disorder mouse model; it also reduced pTau/Tau in animals, suggesting possible relevance to neurodegeneration pathways (still speculative for humans).

  • Menopause symptom relief (multi-ingredient clinical evidence): In a pilot randomized study of a combined nutraceutical including passion flower, participants had improvements in hot flushes, insomnia, fatigue, and irritability over 3–6 months.

  • Anti-allergic/anti-inflammatory potential (constituent evidence): Chrysin (reported as present in blue passion flower) reduced histamine release and pro-inflammatory cytokine expression in mast cell models and reduced anaphylaxis-related outcomes in vivo models.

  • Cardiometabolic/anti-atherosclerotic potential (constituent evidence): In rats, chrysin improved lipid profile and oxidative stress and modulated inflammatory signaling and gut microbiota in a hypercholesterolemia/atherosclerosis model.

  • Possible synergy with other botanicals (preclinical): Passiflora enhanced the potency of Hypericum in antidepressant-related models, suggesting potential for combination approaches (human relevance unknown).

4. Does it have any downsides or side effects?

  • Drug–herb interaction risk (general concern): A UK survey found 33.6% of older adults used herbal medicinal products/dietary supplements concurrently with prescription drugs, and the authors emphasize the need to identify and manage potential interactions. This study does not single out passion flower specifically, but it supports the broader safety issue that concurrent use can pose interaction risks.

  • Clinician unawareness and self-prescribing (pediatric CAM context): In a pediatric headache cohort, CAM (including passion flower among many options) was frequently used and often not known to clinicians; 30% was auto-prescribed. This raises safety concerns about unsupervised use, though the study does not report adverse events attributable to passion flower.

  • Sedation/impairment not established here: The EPM fraction study specifically reported no change in locomotor distance, suggesting the anxiolytic-like signal was not due to sedation in that mouse experiment. However, this does not rule out sedation in humans or with other preparations/doses.

  • Multi-ingredient confounding: The menopausal symptom trial used a combined nutraceutical; safety and side effects attributable to passion flower alone cannot be determined from that study.

  • Constituent vs. whole-plant uncertainty: Several findings relate to chrysin or vitexin as highlighted components. Commercial passion flower products vary widely in composition, so benefits and risks may not generalize across products.

5. Is it beneficial or harmful for any genetic variations (pharmacogenomics)?

The studies reviewed here do not report pharmacogenomic analyses (e.g., effects by CYP450 genotype, transporter polymorphisms, or receptor variants) for passion flower, vitexin, or chrysin. Therefore:

  • No direct evidence from these studies that specific genetic variants make passion flower more beneficial or more harmful.

  • Indirect relevance only: Some mechanistic pathways mentioned (e.g., NF-κB/caspase-1 signaling in chrysin’s anti-allergic effects; Nrf2-related gene expression changes in the atherosclerosis model) could, in principle, be influenced by genetic variation, but the studies do not test genotype-dependent responses.

References

  1. Prevalence of drug-herb and drug-supplement interactions in older adults: a cross-sectional survey.
    Taofikat B Agbabiaka, Neil H Spencer, Sabina Khanom, Claire Goodman (2018) - The British journal of general practice : the journal of the Royal College of General Practitioners
  2. Complementary and alternative medicine (CAM) use in an Italian cohort of pediatric headache patients: the tip of the iceberg.
    D Dalla Libera, B Colombo, G Pavan, G Comi (2014) - Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology
  3. Chrysin reduces hypercholesterolemia-mediated atherosclerosis through modulating oxidative stress, microflora, and apoptosis in experimental rats.
    Subramani Yuvaraj, Sundrasen Sasikumar, Shanavas Syed Mohamed Puhari, Tharmarajan Ramprasath, Nagarethinam Baskaran, Varadaraj Vasudevan, Govindan Sadasivam Selvam (2022) - Journal of food biochemistry
  4. Pharmacological studies in an herbal drug combination of St. John's Wort (Hypericum perforatum) and passion flower (Passiflora incarnata): in vitro and in vivo evidence of synergy between Hypericum and Passiflora in antidepressant pharmacological models.
    Bernd L Fiebich, Rainer Knörle, Kurt Appel, Thomas Kammler, Gabriele Weiss (2011) - Fitoterapia
  5. Improvement in neurogenesis and memory function by administration of Passiflora incarnata L. extract applied to sleep disorder in rodent models.
    Gwang-Ho Kim, Kyunghyun Lim, Hae Sung Yang, Ji-Kwang Lee, Yehlim Kim, Sang-Kyu Park, So-Hyeon Kim, Suhyeon Park, Tae-Hee Kim, Jong-Seok Moon, In Koo Hwang, Yeo Sung Yoon, Hyung Seok Seo, Sung Min Nam, Mi-Yeon Kim, Seul Gi Yoon, Je Kyung Seong, Sun Shin Yi (2019) - Journal of chemical neuroanatomy
  6. The impact of combined nutraceutical supplementation on quality of life and metabolic changes during the menopausal transition: a pilot randomized trial.
    Paola Villa, Inbal D Amar, Carolina Bottoni, Clelia Cipolla, Giorgia Dinoi, Maria C Moruzzi, Giovanni Scambia, Antonio Lanzone (2017) - Archives of gynecology and obstetrics
  7. Anxiolytic effects of fractions obtained from Passiflora incarnata L. in the elevated plus maze in mice.
    C Sampath, M Holbik, L Krenn, V Butterweck (2011) - Phytotherapy research : PTR
  8. Randomized, Double-Blind, Placebo-Controlled, Clinical Study of Passiflora incarnata in Participants With Stress and Sleep Problems.
    Mahesh Kumar Harit, Narendra Mundhe, Sanjay Tamoli, Vinay Pawar, Vedvati Bhapkar, Ganesh Kolhe, Swapnali Mahadik, Anand Kulkarni, Ankit Agarwal (2024) - Cureus
  9. Effects of a fixed herbal drug combination (Ze 185) to an experimental acute stress setting in healthy men - An explorative randomized placebo-controlled double-blind study.
    Sibylle Meier, Manuel Haschke, Catherine Zahner, Esther Kruttschnitt, Jürgen Drewe, Evangelia Liakoni, Felix Hammann, Jens Gaab (2018) - Phytomedicine : international journal of phytotherapy and phytopharmacology
  10. Early effect of NEURAPAS® balance on current source density (CSD) of human EEG.
    Wilfried Dimpfel, Klaus Koch, Gabriele Weiss (2011) - BMC psychiatry
  11. Multivariate analysis of morphological characteristics of two species of passion flower with ornamental potential and of hybrids between them.
    E A Santos, M M Souza, A P Viana, A A F Almeida, J C O Freitas, P R Lawinscky (2011) - Genetics and molecular research : GMR
  12. An open prospective pilot study of a herbal combination "Relief" as a supportive dietetic measure during alcohol withdrawal.
    Kenza Mansoor, Fadi Qadan, Andreas Hinum, Caroline Schneider, Klaus Hechenbichler, Mathias Schmidt, Georg Linsinger, Khalid Matalka (2018) - Neuro endocrinology letters
  13. Chromosome-level genome assembly of Protandrena (Anthemurgus) passiflorae (Hymenoptera: Andrenidae), a host-plant specialist bee.
    Katherine A Parys, Rena M Schweizer, Ligia R Benavides, Scott M Geib, Sheina B Sim, Jay D Evans, Michael G Branstetter (2025) - G3 (Bethesda, Md.)


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This article summarizes published research for educational purposes. It is not medical advice. Talk to your doctor before starting, stopping, or changing any supplement or medication.

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