Pellitory: A Comprehensive Encyclopedic Reference
1. Nomenclature, Botanical Identity, and Natural Sources
The common name Pellitory is applied to two botanically distinct and medicinally separate plants that share a name derived from the ancient Greek word for "fire" (πῦρ, pyr), alluding to their pungent or burning sensory qualities. Both "pyrethrum" and "pellitory" derive ultimately from the ancient Greek for fire. The two plants are:
- Pellitory Root / Spanish Pellitory / Akarkara: Anacyclus pyrethrum (L.) Lag. (synonym: Anacyclus pyrethrum DC.), family Asteraceae. This species — also known as Mount Atlas daisy, bertram, or Akarkara — is a species of flowering plant in the daisy family Asteraceae, native to Mediterranean Europe and parts of North Africa, but also naturalised in other parts of Europe, India, and Pakistan. This herbaceous perennial resembles chamomile species in habitat and appearance.
- Pellitory-of-the-Wall: Parietaria officinalis L. (eastern pellitory-of-the-wall; also Parietaria judaica, the spreading or wall pellitory), family Urticaceae. This is a plant of the nettle family whose leaves are non-stinging, and which grows on rubbish and on walls, hence the name.
The plants known as pellitory-of-the-wall and spreading pellitory belong to a different family, the nettles (Urticaceae). These two plants are covered separately in this article, with the scientific literature on Anacyclus pyrethrum being substantially more extensive.
1.1 Anacyclus pyrethrum — Pellitory Root (Akarkara)
Akarkara, scientifically known as Anacyclus pyrethrum (L.) Lag. or Anacyclus pyrethrum DC., is a perennial plant belonging to the Asteraceae family. Commonly referred to as Pellitory Root, Spanish Pellitory, or Mount Atlas Daisy, this herb holds a significant place in traditional medicine systems, particularly Ayurveda, Unani, and Siddha, and is native to North Africa, the Mediterranean region, and parts of Asia.
The plant is distinguished by its daisy-like yellow-white flowers and sprawling, low-lying stems. Its medicinal power is concentrated in its roots — cylindrical, tough, and light brown — often emitting a tingling or numbing sensation when chewed. Dried root is almost cylindrical, slightly twisted, and tapering downwards, generally crowned with a tuft of hair, brownish and fissured on the outside with shining black markings. The fracture is short, presenting a radiate structure and numerous oleoresin glands. The taste is pungent with a slight odor.
It is commonly known as pellitory, Aqar Qarha, Oud El Attas, African pyrethrum, and Akarkara. It is endemic to Morocco, Algeria, and Spain, and it has been introduced in India, Australia, France, Germany, Nepal, Pakistan, Poland, and Ukraine.
Common preparations and forms: The plant is widespread in Morocco and Algeria, and most of its parts are used in traditional medicine, with the roots being the most important. The root is used in the form of dried powder, hydroalcoholic extracts, aqueous decoctions, and standardized ethanolic extracts. It is also incorporated into topical formulations and cosmeceutical products.
Although one might assume from the specific epithet pyrethrum that this plant contains pyrethrins, it does not.
1.2 Parietaria officinalis — Pellitory-of-the-Wall
Pellitory-of-the-wall is a bushy, herbaceous perennial plant that grows to a height of 30–60 cm. It features reddish, brittle stems and narrow, stalked lanceolate-ovate leaves measuring 2–4 cm in length. The name of this genus, Parietaria, is derived from the Latin word paries (a wall), for it is very commonly found growing from crannies in dry walls. Indigenous to Europe, the plant is common in southern countries, where it is found on walls and in dry stony places.
The aerial parts — leaves, stems, and flowers — constitute the medicinal portion. The aerial parts are gathered in summer when the plant is in flower.
2. Traditional and Historical Use
2.1 Anacyclus pyrethrum
Native to North Africa and the Mediterranean basin, the plant's dried roots have been a valued part of traditional health practices for hundreds of years, especially in Ayurveda, Unani, and Siddha medicine.
Ayurveda (India): Ayurveda and Siddha medicine have mentioned medical uses for this plant root. An authentic Ayurvedic text, the Shodhal Nighantu (Gadanigraha), described Akarkara as a potent tonic supporting healthy reproductive and nervous systems. In classical Ayurvedic texts, Akarkara is classified as a Rasayana (rejuvenative), Vajikarana (aphrodisiac), and Medhya (nootropic/cognitive enhancer). In Ayurveda, Anacyclus pyrethrum has been used as a brain tonic.
Unani Medicine: Anacyclus pyrethrum, commonly known as "Aqarqarha" in Unani medicine, has been a prominent herb in traditional medicine systems for centuries due to its diverse therapeutic properties.
North African and Moroccan traditional medicine: The plant is widely used in Moroccan traditional medicine to treat inflammatory and painful diseases. Many traditional uses are reported in previous research, such as for rheumatism, sciatica, colds, neuralgia, and paralysis. The species is considered to be a sialagogue and used in the treatment of stomach ailments, diseases of inflammation of the mouth, against cysts in the genital tract, and to relieve toothaches.
Traditional ailments addressed: The root has been traditionally employed to address ailments like toothache, gingivitis, dental caries, periodontitis, Ludwig's angina, migraine, epilepsy, hemiplegia, facial palsy, headache, hysteria, atony/flaccidity, tremor, nasal congestion, anaphrodisia, premature ejaculation, amenorrhea, coccydynia, sciatica, backache, polyarthritis, general weakness, rheumatism, cholera, and edema.
Sexual and reproductive use: Anacyclus pyrethrum has been used as Vajikaran Rasayana (aphrodisiac) in traditional Indian Ayurvedic medicine to treat male sexual dysfunction, including infertility.
Entry into India: The plant entered India through Muslim rulers and traders.
2.2 Parietaria officinalis (Pellitory-of-the-Wall)
Pellitory-of-the-wall has a long history of use in traditional medicine systems across Europe and the Mediterranean. The herb has been widely used to treat urinary conditions, including kidney and bladder stones, nephritis, and cystitis.
For more than 2,000 years, the herb has been valued as a diuretic, a soother of chronic coughs, and a balm for wounds and burns.
The 17th-century herbalist Nicholas Culpeper described its traditional applications, including for: hot, burning urine, strangury, gravel and stones; a syrup made of the juice with honey for those prone to edema; and for chronic and dry coughs, shortness of breath, wheezing, and bronchial asthma.
Traditional external applications included: applications to swellings, tumors, and running ulcers; applications to erysipelas, shingles, herpes, burns, and fresh wounds (using juice or distilled water); gargles for sore throat; holding the juice in the mouth for toothache; and use in enemas to clear heat and ease pain.
A traditional combination remedy for kidney stones blended equal parts of pellitory of the wall, wild carrot (Daucus carota), and parsley piert (Alchemilla aphanes).
In European herbal medicine, it is regarded as having a restorative action on the kidneys, supporting and strengthening their function.
3. Key Phytochemical Constituents
3.1 Anacyclus pyrethrum
A. pyrethrum is a rich source of phytochemical constituents such as alkaloids (pellitorin) and N-alkylamides. The species also contains pyrethrins, sesamin, traces of essential oils, and a wide range of other chemical compounds.
The root's principal alkaloid profile has been characterized by HPLC-MS/MS. The major alkaloid is N-isobutylamide — pellitorine — accompanied by a mixture of other alkylamides including anacycline, N-isobutyl-2,4-heptadiene-6-monoynamide, N-isobutyl-2,4-octadiene-6-monoynamide, (2,4)-dodecadiene-N-tyamide, N-isobutyl-2,4-hexadiynamide, acetanilide, and N-methyl-isobutyl-2,4-decadienamide, among others. These compounds are considered molecules with promising biocidal properties.
A. pyrethrum is rich in bioactive compounds including saturated fatty acids (isovaleric acid, decanoic acid, lauric acid, myristic acid, octadecanoic acid, palmitic acid), unsaturated carboxylic acid (cinnamic acid), fructans (inulin), phenols, polyphenols, tannins, flavonoids, pellitorine, pyrethrin, anacycline, herculin, sesamin, and polysaccharides.
Phytochemical screening has led to the identification of various secondary metabolites such as alkaloids, reducing compounds, tannins, flavonoids, and coumarins. The species also contains saponins, sesamin, inulin, gum, and traces of essential oil. The most important phytoconstituents present in its root are N-isobutyldienediynamide and polysaccharides.
The major constituent pellitorine (an N-alkylamide) has been characterized separately. The plant consists of several N-alkylamides, with pellitorine as the main constituent. AP extracts are known to be biologically active, and some products for topical administration containing AP plant extracts are commercially available with functional cosmeceutical claims.
3.2 Parietaria officinalis
The leaves and flowers of P. officinalis contain the flavonoids kaempferol-3-bioside, the 3-glucosides and 3-rutinosides of quercetin, kaempferol and isorhamnetin, 3-sophorosides of quercetin and kaempferol, and 3-neohesperosides of kaempferol and isorhamnetin. They also contain caffeoylmalic acid and two pyrrole acids.
The plant also contains mucilages, tannins, and a notable potassium content. Flavonoids are thought to confer diuretic properties alongside the plant's wealth in potassium.
4. Established and Proposed Mechanisms of Action
4.1 Anacyclus pyrethrum
Anti-inflammatory action (COX/LOX inhibition): In vitro inhibition of cyclooxygenase (COX) and 5-lipoxygenase (LOX) by alkamides isolated from A. pyrethrum has been reported. Mechanisms may involve inhibiting inflammatory pathways such as COX and LOX.
Analgesic mechanisms: Both central and peripheral pain-relieving activity has been observed in animal studies.
Sialagogue (salivation-stimulating) effect: The N-alkylamides, particularly pellitorine, produce a tingling, numbing, and salivation-stimulating sensation when the root is chewed or applied to oral mucosa, which is the pharmacological basis for its traditional use in oral and dental conditions.
Transdermal delivery of pellitorine: The N-alkylamide pellitorine from AP has been investigated for local skin pharmacokinetics using a Franz diffusion cell setup. The study demonstrated that pellitorine is able to cross the stratum corneum and subsequent skin layers. A significantly higher permeability coefficient was observed when the AP extract (Kp=2.3 × 10⁻⁴ cm/h) was administered, compared to purified pellitorine alone (Kp=1.1 × 10⁻⁴ cm/h).
Androgenic / spermatogenic mechanisms: Aphrodisiac activity may be due to an increase in the production or effect of androgens; studies have investigated the androgenic and spermatogenic potential of the alkylamide-rich ethanol solution extract.
Antioxidant and neuroprotective effects: The therapeutic ability of Anacyclus pyrethrum may be attributed to its antioxidant effect, which in turn prevents DNA oxidative damage and cytotoxicity. Its antioxidant potential has been correlated with its uses as an anticonvulsant and brain tonic.
Anticonvulsant mechanisms: The possible anticonvulsant mechanism has been studied by testing the effect of atropine and scopolamine on seizure parameters; ethanol extract and alkylamides increased the seizure onset time and decreased the seizure duration compared to the control group (p < 0.001).
Immunostimulatory effect: A study evaluated the effect of Anacyclus pyrethrum on normal and chemically suppressed immune systems in vivo. Immunostimulant activity increased two-fold upon doubling the dosage of extract administered. Significant improvement was observed in the humoral component and a highly significant effect was observed in the cellular components of immunity.
4.2 Parietaria officinalis
The whole herb, gathered when in flower, is cholagogue, slightly demulcent, diuretic, laxative, refrigerant, and vulnerary. The diuretic mechanism is attributed to flavonoid constituents and potassium content. Its diuretic and soothing properties help to reduce irritation and promote the elimination of waste products.
5. Scientific Evidence by Area of Use
5.1 Analgesic and Anti-inflammatory Activity (Anacyclus pyrethrum)
Strength of evidence: Preclinical (animal and in vitro) only. No adequate human clinical trials.
A 2020 study published in Molecules (PMC, MDPI) evaluated the chemical composition, analgesic, anti-inflammatory, and wound-healing properties of hydroalcoholic extracts of different parts of A. pyrethrum. The plant is a wild species used in traditional medicines. The study examined chemical composition, analgesic, anti-inflammatory, and wound-healing properties of hydroalcoholic extracts from roots, seeds, leaves, and capitula. Phytochemical analysis was conducted by GC-MS, analgesic activity was evaluated in mice using acetic acid and formaldehyde methods, anti-inflammatory activity was tested using the inhibitory method of edema induced in rats, and wound healing was explored by excision and incision wound models in rats.
The extracts of different parts exhibited promising anti-inflammatory, analgesic, and wound-healing effects, with percentages of inhibition up to 98%, 94%, and 100%, respectively. Specifically, the extracts showed a significant analgesic effect against pain caused by acetic acid compared to the control lot, with an inhibition percentage ranging from 12% to 94% (p < 0.001); the reference product diclofenac showed a pain inhibition percentage of 43%.
A separate study investigating antinociceptive, anti-inflammatory, and antioxidant activities used aqueous (AEAPR) and methanol (MEAPR) extracts of A. pyrethrum roots. The anti-inflammatory effect was determined in xylene-induced ear edema and Complete Freund's Adjuvant (CFA)-induced paw edema models. Antinociceptive activity of AEAPR and MEAPR at doses of 125, 250, and 500 mg/kg administered by gavage was examined in mice using acetic acid-induced writhing, hot plate, and formalin tests, and mechanical allodynia was assessed in CFA-induced paw edema. In vitro antioxidant activities were determined using the DPPH radical scavenging method, ferric reducing power, and β-carotene–linoleic acid assay systems. AEAPR and MEAPR produced significant reductions in CFA-induced paw edema and xylene-induced ear edema.
This study contributed evidence on the potential analgesic, anti-inflammatory, and wound-healing properties of A. pyrethrum. All studies in this area are, however, preclinical, and results cannot be directly extrapolated to human use.
5.2 Aphrodisiac, Androgenic, and Reproductive Activity (Anacyclus pyrethrum)
Strength of evidence: Preclinical animal studies only. No published, peer-reviewed randomized controlled trials in humans.
The androgenic and spermatogenic potential of an alkylamide-rich ethanol solution extract was evaluated in a controlled animal study. Male Wistar strain rats weighing between 150 and 180 g were randomly divided into five groups. The ethanol solution extract was administered in doses of 50, 100, and 150 mg/kg for a period of 28 days, and the results were compared with control and testosterone-treated rats. A significant anabolic effect was observed after administration of extracts compared to the placebo group, suggesting a testosterone-type action of the extracts. The experiment clearly suggests anabolic steroidal effect of Anacyclus pyrethrum.
A study examining effects on diabetic male rats investigated hormonal parameters: the objective was to evaluate the effect of alcoholic root extract of Anacyclus pyrethrum (AP) on FSH, LH, testosterone, and sperm count in diabetic male rats. The study was conducted on 60 Wistar-Albino male rats divided into six groups; diabetes was induced with an intraperitoneal injection of streptozotocin (STZ, 60 mg/kg).
Additionally, aqueous extract of roots was studied for its effect on sexual behavior, spermatogenesis, and sperm count. Fructose levels in seminal vesicles of albino rats were also recorded. Two doses — 50 and 100 mg/kg of aqueous extract — on administration in albino rats showed pronounced anabolic and spermatogenic effects.
A 2024 PMC study investigated A. pyrethrum's ability to protect male rats against cadmium-induced reproductive toxicity. Cadmium was shown to reduce male fertility by causing oxidative stress. Anacyclus pyrethrum is a well-known medicinal plant. Most of its parts, notably the roots, have excellent antioxidant and anti-inflammatory properties. The study investigated the potential ability of Anacyclus pyrethrum to protect male rats against cadmium reproductive toxicity.
The systematic review by Jawhari et al. (2022) in PMC concluded that further research must be carried out in order to establish any relationship between the traditional uses, phytochemistry and toxicity. Moreover, A. pyrethrum is quite promising as a medicinal agent, so further clinical trials should be performed to prove its efficacy.
5.3 Anticonvulsant and Neuroprotective Activity (Anacyclus pyrethrum)
Strength of evidence: Preclinical animal studies only.
A study evaluated the effect of hydroalcoholic extract of A. pyrethrum root (HEAP) on seizures and cognitive impairment in experimental models. Male Wistar rats were used. HEAP was administered in doses of 50, 100, 250, and 500 mg/kg in a pentylenetetrazole (PTZ) model and 250, 500, and 1000 mg/kg in a maximal electroshock (MES) model. Myoclonic jerk latency and generalized tonic clonic seizures (GTCS) were noted in PTZ, while tonic hind limb extension (THLE) was observed in MES seizures. HEAP showed 50%, 66.7%, 83.3%, and 100% protection at 50, 100, 250, and 500 mg/kg, respectively, against GTCS in PTZ-induced seizures.
A separate study on pentylenetetrazole-induced kindling assessed HEAP at 250 and 500 mg/kg: pre-treatment showed significant increase in myoclonic jerk latency and delay in the development of kindling. A significant decrease in mortality was observed at higher doses (250 and 500 mg/kg). Pre-treatment with HEAP significantly increased the number of platform crossings and decreased the escape latency (compared to the PTZ group), showing protection against memory deficit. HEAP pre-treatment also attenuated the oxidative stress induced by PTZ kindling. PTZ-induced kindling increased the ROCK II expression, whereas HEAP pre-treatment attenuated this increase. The authors concluded that HEAP pre-treatment showed antiepileptic effect and also showed protection against cognitive impairment by decreasing oxidative stress and ROCK II expression in PTZ-kindled mice.
Additional research on pilocarpine-induced epilepsy showed that petroleum ether extract of A. pyrethrum can provide significant protection against seizures induced by pentylenetetrazole (PTZ). This dose-dependent extract increased the latency of induced seizures and reduced the duration of epilepsy. The extracts showed a reduction in neurological symptoms and seizure severity compared to the negative control.
5.4 Cognitive / Memory-Enhancing Activity (Anacyclus pyrethrum)
Strength of evidence: Preclinical animal studies only.
To explore the potential effect of ethanolic extract of Anacyclus pyrethrum in memory dysfunction, memory impairment was produced by administration of scopolamine (1 mg/kg, i.p.) in rats. Passive avoidance paradigms, elevated plus maze, and social learning tasks were used to assess learning and memory. The A. pyrethrum extract-treated group decreased transfer latency in the elevated plus maze model, which is indicative of cognition improvement.
5.5 Antidepressant and Anxiolytic Activity (Anacyclus pyrethrum)
Strength of evidence: Preclinical animal studies only.
The pharmacological properties of the aqueous extract of A. pyrethrum demonstrated anxiolytic and antidepressant activities at a dose of 200 mg/kg in animal models, while no antinociceptive effect was observed.
5.6 Antimicrobial Activity (Anacyclus pyrethrum)
Strength of evidence: In vitro only.
The alkaloids identified by HPLC-MS/MS — pellitorine and related alkylamides — are considered molecules with promising biocidal properties. Experimental studies have been conducted for antimicrobial, antioxidant, anti-inflammatory, hepatoprotective, anticancer, neuroprotective, antidepressant, and aphrodisiac activities. No clinical studies are available for antimicrobial applications.
5.7 Urinary Tract and Renal Support (Parietaria officinalis)
Strength of evidence: Traditional use; limited in vitro antimicrobial evidence; no controlled human clinical trials identified.
Pellitory of the wall is an herb that has been traditionally used for treating disorders of the kidney as well as urinary bladder. Parietaria species have numerous therapeutic uses, and infusions and decoctions prepared with these herbs may be used both internally and externally. It is an efficacious remedy (in traditional practice) for kidney and bladder stones and other complaints of the urinary system such as cystitis and nephritis.
Recent in vitro studies have demonstrated the antimicrobial properties of pellitory extracts, particularly against bacterial and fungal pathogens. These findings support its traditional use in treating infections and wounds.
There is no specification regarding effectual and safe dosage of infusions and decoctions prepared with this herb.
6. Body Systems and Health Areas
6.1 Anacyclus pyrethrum
- Nervous system: Anticonvulsant, antidepressant, anxiolytic, cognitive/memory-enhancing, and neuroprotective effects — all currently demonstrated in preclinical models only. Reported properties include sialagogue, aphrodisiac, immunostimulant, antidepressant, antimicrobial, insecticide, anesthetic, anti-inflammatory, anticonvulsant, antioxidant, antidiabetic, and memory enhancer activities.
- Male reproductive system: Traditional aphrodisiac and Vajikarana tonic; animal studies suggest anabolic, androgenic, and spermatogenic effects. Widely recognized in Ayurveda as a tonic and rejuvenator; the roots are also considered aphrodisiac and sexual stimulant.
- Musculoskeletal and inflammatory system: Used in North African traditional medicine for rheumatism, sciatica, and joint pain; laboratory evidence supports anti-inflammatory action via COX/LOX inhibition.
- Oral health: As a sialagogue, it stimulates salivation; traditional use in toothache, gingivitis, and dental pain. The species is considered a sialagogue and used in the treatment of stomach ailments, diseases of inflammation of the mouth, and to relieve toothaches.
- Immune system: Immunostimulatory polysaccharide fractions have been characterized in animal studies. The plant has an antidiabetic, insecticidal, and immunostimulatory effect, as well as aphrodisiac and antioxidant potentials, and various other important medicinal properties.
- Metabolic / antidiabetic: Preclinical evidence of anti-hyperglycemic activity in animal models.
6.2 Parietaria officinalis
- Urinary system: Primary traditional application — diuretic, support for kidney stones, cystitis, nephritis. Pellitory of the wall possesses very effective diuretic properties and is an excellent resource when it is essential to enhance the flow of urine.
- Respiratory system: The plant's emollient properties have been used to alleviate dry coughs and bronchial conditions.
- Integumentary / wound healing: The leaves can be employed externally as a poultice on wounds, and have a soothing effect on simple burns and scalds.
- Liver / biliary system: The whole herb is cholagogue (stimulates bile flow) and slightly demulcent.
7. Dosage Forms and Reported Dosages
7.1 Anacyclus pyrethrum — Reported in Studies
The following dosages appear in the cited research literature and are reported exclusively from animal studies; no standardized human dosages have been established in clinical trials.
- Ethanol solution extract (androgenic/spermatogenic study): Male Wistar rats were used; the ethanol solution extract was administered in doses of 50, 100, and 150 mg/kg for a period of 28 days.
- Hydroalcoholic extract, anti-inflammatory/analgesic study: Antinociceptive activity of AEAPR and MEAPR at 125, 250, and 500 mg/kg, administered by gavage, was examined in mice.
- Hydroalcoholic extract, anticonvulsant study: HEAP was administered in doses of 50, 100, 250, and 500 mg/kg in the PTZ model and 250, 500, and 1000 mg/kg in the maximal electroshock (MES) model.
- Aqueous extract, anxiolytic/antidepressant study: Different doses (100, 200, 400, and 800 mg/kg) were administered to rats via gavage; anxiolytic and antidepressant activities were demonstrated at a dose of 200 mg/kg.
- Aqueous extract, anabolic/reproductive study: Two doses — 50 and 100 mg/kg of aqueous extract — on administration in albino rats showed pronounced anabolic and spermatogenic effects.
7.2 Parietaria officinalis — Reported Preparations
Two or three infusions a day of a couple of dry spoonfuls of leaves per liter of water represent a traditional preparation used for its diuretic effects. There is no specification regarding effectual and safe dosage of infusions and decoctions prepared with this herb in the scientific literature.
8. Safety Considerations and Notable Interactions
8.1 Anacyclus pyrethrum — Toxicology and Safety
Acute toxicity: Multiple animal studies have assessed oral acute toxicity. The results revealed that the acute toxicity demonstrated the safety of the aqueous extract (AEAP) at tested doses, with no observed mortality or significant alterations. The aqueous extract possesses an LD50 value greater than 5000 mg/kg. A study on hydroethanolic extracts from two varieties found: the extracts of different parts of both plants induced no signs of toxicity or mortality during the observation period, excluding capitulum and seed extracts, which induced slight sedation at a dose of 2000 mg/kg. The LD50 of the extracts was estimated to exceed 2000 mg/kg.
Liver enzyme changes at high doses: The administration of A. pyrethrum var. pyrethrum roots at a dose of 300 mg/kg resulted in significantly increased AST levels. The A. pyrethrum var. depressus root extract induced significant increases in the levels of both transaminases (ALT and AST). The remaining extracts of both plants at a dose of 500 mg/kg significantly increased AST levels.
Histopathological findings at very high doses: High doses of 2000 mg/kg caused histopathological changes in vital organs of mice.
Long-term safety unknown: Subacute and chronic toxicity studies are necessary to assess long-term safety of these extracts.
Skin irritation (topical use): Excessive exposure to some types of pyrethroids may cause skin irritation in sensitive individuals.
Asteraceae allergy: Because A. pyrethrum belongs to the Asteraceae family, individuals with known allergies to related plants (e.g., chamomile, ragweed, chrysanthemums) may be at risk of cross-reactivity.
8.2 Parietaria officinalis — Allergenicity
The most thoroughly documented safety concern for Parietaria species is their pollen's potent allergenicity, which is one of the most extensively studied plant allergen systems in Europe.
Parietaria is a genus of dicotyledonous weeds of the Urticaceae family, and its pollen grain is one of the most important allergenic sources in the Mediterranean area. Species belonging to this genus induce IgE responses in approximately 10 million people.
Major allergens — Par o 1 and Par j 1: Par j 1 represents a major allergenic component of Parietaria judaica pollen, since it is able to induce an immunoglobulin E (IgE) response in 95% of Pj-allergic patients. It belongs to the non-specific lipid transfer protein family, sharing with them a common three-dimensional structure.
For P. officinalis pollen, the major allergen Par o 1 is similarly potent: allergenicity was assayed in vivo and in vitro; 29/29 Parietaria-allergic patients were skin positive to Par o I and possessed high level of specific serum IgE antibody as determined by radioallergosorbent test (RAST). Par o I contained dominant epitopes for human IgE, inhibiting to 85% the pollen extract RAST performed with a pool of sera from allergic patients.
The allergens of the two more common species, Parietaria judaica and Parietaria officinalis, show molecular weights ranging between 10 and 14 kD, and the allergens of the two extracts are highly cross-reactive.
Parietaria judaica (wall pellitory) is one of the most common pollen allergen sources, mainly in the Mediterranean area but also along the southern coast of the UK, France, Australia, California, and Eastern Europe. Its pollen is responsible for severe forms of respiratory allergy (allergic rhinitis, asthma), which may be due to the fact that the plant has an unusually long period of pollination ranging from February to November.
Contraindication in hay fever: Pellitory-of-the-wall should not be prescribed to people with hay fever or other allergic conditions. Many studies confirm that the pollen of pellitory of the wall (specifically the judaica variation) is a notable allergen, particularly in Mediterranean regions. Studies have focused on the allergenic potential and cross-reactivity of Parietaria species, which is important for allergy diagnosis and management. It is, therefore, contraindicated in hay fever.
9. State of Evidence and Research Gaps
The 2022 systematic review of A. pyrethrum published in PMC summarized the state of knowledge: Anacyclus pyrethrum is an interesting medicinal plant of the Asteraceae family, endemic to Morocco and Algeria, used in traditional medicine to treat many diseases. The review covered botany, traditional use, phytochemistry, pharmacological use, and toxicology. The collected data confirm the pharmacological potential of this species. Experimental studies have been conducted for pharmacological activities including antimicrobial, antioxidant, anti-inflammatory, hepatoprotective, anticancer, neuroprotective, antidepressant, and aphrodisiac activities. Numerous studies show the richness of the species in secondary metabolites — terpenoids, polyphenols, alkaloids, etc. — justifying its traditional therapeutic use. However, there are few studies on the fractionation of its compounds and on their isolation.
Critically, further research must be carried out in order to establish any relationship between the traditional uses, phytochemistry, and toxicity. Moreover, A. pyrethrum is quite promising as a medicinal agent, so further clinical trials should be performed to prove its efficacy.
For Parietaria officinalis, the medicinal application literature is largely historical and based on traditional European herbal medicine, with modern pharmacological investigation limited primarily to allergen characterization rather than therapeutic efficacy. No published randomized controlled trials in humans are available for either pellitory species across the core areas of claimed therapeutic benefit as of the available literature.
References
- Jawhari FZ et al. Phytochemistry, Biological and Pharmacological Activities of the Anacyclus pyrethrum (L.) Lag: A Systematic Review. Plants (MDPI). 2022; PMC9573456.
- Jawhari FZ et al. Anacyclus pyrethrum (L): Chemical Composition, Analgesic, Anti-Inflammatory, and Wound Healing Properties. Molecules. 2020;25:5469. PMC7700217.
- Manouze H et al. Anti-inflammatory, Antinociceptive, and Antioxidant Activities of Methanol and Aqueous Extracts of Anacyclus pyrethrum Roots. Frontiers in Pharmacology. 2017. PMC5591861.
- Sharma V et al. Androgenic and Spermatogenic Activity of Alkylamide-Rich Ethanol Solution Extract of Anacyclus pyrethrum DC. Andrologia. 2012. PubMed PMID: 22473789.
- Pahuja M et al. Root extract of Anacyclus pyrethrum ameliorates seizures, seizure-induced oxidative stress and cognitive impairment in experimental animals. Epilepsy Research. 2012. PubMed PMID: 21993359.
- Root extract of Anacyclus pyrethrum ameliorates seizures, seizure-induced oxidative stress and cognitive impairment in experimental animals. ScienceDirect.
- Effect of Anacyclus pyrethrum on Pentylenetetrazole-Induced Kindling, Spatial Memory, Oxidative Stress and Rho-Kinase II Expression in Mice. Neurochemical Research. Springer.
- Veryser L et al. Quantitative transdermal behavior of pellitorine from Anacyclus pyrethrum extract. PubMed PMID: 25481393.
- Boonen J et al. LC-MS N-alkylamide profiling of an ethanolic Anacyclus pyrethrum root extract. Planta Med. 2012. PubMed PMID: 23047251.
- Jawhari FZ et al. Evaluation of the acute toxicity of the extracts of Anacyclus pyrethrum var. pyrethrum (L.) and Anacyclus pyrethrum var. depressus Maire in Swiss mice. Vet World. 2021. PMC7994131.
- The Toxicological and Pharmacological Evaluation of the Anacyclus pyrethrum Aqueous Extract. MDPI Nutraceuticals. 2024.
- Anacyclus pyrethrum enhances fertility in cadmium-intoxicated male rats by improving sperm functions. PMC11600599. 2024.
- A Complete Review of Ethnopharmacology, Pharmacology and Phytochemistry of Anacyclus pyrethrum DC. Traditional and Integrative Medicine Journal.
- Anacyclus pyrethrum — Wikipedia.
- Parietaria officinalis — Wikipedia.
- Pellitory of the Wall (Parietaria officinalis): Benefits, Uses, Safety. Herbal Reality.
- Parietaria officinalis — Plants For A Future (PFAF) Database.
- Pellitory-of-the-Wall. A Modern Herbal, Mrs. M. Grieve. Botanical.com.
- Hypoallergenic Variants of the Parietaria judaica Major Allergen Par j 1. International Archives of Allergy and Immunology. Karger.
- Basic isoforms of Par o 1, the major allergen of Parietaria officinalis pollen. PubMed PMID: 8748722.
- Purification and characterization of Par o I, major allergen of Parietaria officinalis pollen. PubMed PMID: 1752693.
- The Allergens of Parietaria. International Archives of Allergy and Immunology. Karger.
- Expression and characterization of recombinant Par j 1 and Par j 2 resembling the allergenic epitopes of Parietaria judaica pollen. PMC6803649.
- The Effects of Anacyclus pyrethrum Alcoholic Root Extract on FSH, LH, Testosterone and Sperm Count in Diabetic Male Rats. Zahedan Journal of Research in Medical Sciences.
Go back