Cade juniper

Cade Juniper (Juniperus oxycedrus L.): A Comprehensive Reference

1. Identity: Botanical Classification, Names, and Natural Source

1.1 Taxonomy and Nomenclature

Juniperus oxycedrus, vernacularly called Cade, cade juniper, prickly juniper, prickly cedar, or sharp cedar, is a species of juniper native across the Mediterranean region, growing on a variety of rocky sites from sea level. The plant was formally described in 1753 by Carolus Linnaeus in Species Plantarum. In German it is called Zeder-Wacholder; in French, genévrier cade or cèdre piquant; and in Italian, ginepro pungente.

The specific epithet oxycedrus means "sharp cedar," and this species may have been the original cedar or cedrus of the ancient Greeks. Juniperus oxycedrus L. (Cupressaceae) is one of the ten species that comprise the section Juniperus (= Oxycedrus) of the genus Juniperus throughout the world. This shrub or tree has a typical Mediterranean distribution. In Morocco it is known by the vernacular name "Taqqa."

1.2 Botanical Description

Juniperus oxycedrus is very variable in shape, forming a spreading shrub 2–3 metres tall to a small erect tree 10–15 m tall. It is an evergreen, bushy plant or small tree forming red galbuli (berry-like cones). All plant parts including the galbuli contain highly aromatic essential oil. It is in leaf all year, and the seeds ripen in October. The species is dioecious — individual flowers are either male or female, found on separate plants.

1.3 Geographic Distribution

Juniperus oxycedrus is native across the Mediterranean region from Morocco and Portugal, north to southern France, east to westernmost Iran, and south to Lebanon and Israel, growing on a variety of rocky sites from sea level up to 1600 m elevation. The species is native to France, Italy, Morocco, Portugal, Sardinia, Spain, and Tunisia. It thrives in hot, dry summers and mild winters, is drought-tolerant, and grows well in poor, rocky, or sandy soils.

1.4 The Principal Preparation: Cade Oil (Juniper Tar)

The main use of J. oxycedrus is to prepare the so-called oil of cade (also known in pharmacy as juniper tar) by destructive distillation of the branches and wood of the plant. Cade oil comes from Juniperus oxycedrus heartwood through destructive dry distillation — high-heat wood breakdown — followed by distillation to separate the essential oil from tar. It is primarily produced through destructive distillation of the wood, followed by rectification to remove carcinogenic impurities such as polynuclear hydrocarbons, ensuring safer use in various applications.

This distinguishes it from other juniper-derived oils, which are typically obtained via steam distillation of needles or berries rather than wood pyrolysis. The process yields a dark brown, thick oil with smoky-phenolic characteristics.

1.5 Commercial and Cosmetic Forms

Rectified cade oil is used as a fragrance component in soaps, detergents, creams, lotions, and perfumes. The ripe fruit of Juniperus oxycedrus is also alcohol-extracted to produce Juniperus oxycedrus Extract. Juniperus Oxycedrus Tar is the volatile oil from the wood of J. oxycedrus. The extracts function as biological additives in cosmetic formulations, and Juniperus Oxycedrus Tar is used as a hair-conditioning agent and a fragrance component.

2. Traditional and Historical Use

2.1 Ancient and Pre-Modern Use

Historically, cade oil has been employed in traditional medicine across regions like Morocco and Europe for treating skin ailments, including eczema, psoriasis, and dandruff, due to its anti-inflammatory, antimicrobial, and antiparasitic properties. These therapeutic uses date back to historical times, including the Middle Ages, with records of its application in folk remedies.

The oil has a long history in animal care (ethnoveterinary use) and skin treatment across Asian and Mediterranean regions, where people traditionally used it for snakebites, leprosy, toothaches, lice control, and various skin conditions including psoriasis. Historically, it was recognized for its pain-relieving (analgesic), anti-itch (antipruritic), antiseptic, disinfectant, anti-parasite (parasiticide), and worm-expelling (vermifuge) properties.

2.2 Traditional Uses by Region and Culture

Morocco: In Moroccan folk medicine, cade oil is used for the treatment of bronchitis, abdominal pain and diarrhea, psychiatric disorders, cancer, fever, cephalgia (headache), angina, weight loss, common cold, and hypotonia. This oil is widely used in traditional Moroccan medicine for its analgesic, digestive, bronchopulmonary, and dermatological properties.

Algeria: In Algerian folk medicine, J. oxycedrus is used as a diuretic, stimulant, stomach tonic, and pulmonary and depurative disinfectant. Extracts from the wood and branches (oil of cade) are used by the pharmaceutical industry against skin diseases (eczemas, psoriasis) and as a vermifuge. In Algerian traditional medicine, it is revered for its diuretic, stimulative, and stomachic tonic properties, and is highly valued for its effectiveness as a pulmonary and depurative disinfectant.

Turkey: In Turkey, cones in decoction are used to ease abdominal pain; the freshly crushed cones are used to treat heart diseases and combat stomach aches.

Veterinary use: Veterinary practitioners have traditionally employed the oil for parasitic skin problems. In formulations such as shampoos and ointments, diluted cade oil is used to help alleviate symptoms in dogs, poultry, and other animals by repelling fleas, ticks, mites, and ringworm, while promoting healing of affected skin.

2.3 Traditional Application Methods

Cade oil was largely employed in the treatment of chronic eczema, psoriasis, and other skin diseases of man, and has also been found to be an efficient parasiticide in psora (mange) and favus (scalp fungal infection). It was applied sometimes at full strength, sometimes diluted with a bland oil, well rubbed into the affected parts with the fingers or with a cloth, and was also made into ointments, and especially into soaps.

In broader traditional medicine contexts, Juniperus oxycedrus has been utilized for treating several illnesses including diabetes, heart diseases, asthma, kidney disorders, and abdominal pain. The leaves (known as "tagga" in northeast Algeria) are used in infusion in the Rif region of Morocco to treat asthma and cough.

3. Key Constituents and Active Compounds

3.1 Chemical Composition of Cade Oil (Destructive Distillate)

Rectified cade oil from Juniperus oxycedrus wood is primarily composed of sesquiterpenes, phenols, and hydrocarbons, which define its potent woody and phenolic profile. These chemical classes are identified through gas chromatography-mass spectrometry (GC-MS) analyses. Sesquiterpenes dominate, often comprising a significant portion of the oil, alongside phenolic compounds responsible for its distinctive smoky, tar-like scent.

Key major constituents based on GC-MS data from rectified samples include delta-cadinene (up to 28%), cis-calamenene (around 15%), and beta-caryophyllene (5–10%). Other prominent sesquiterpenes are alpha-cedrene (up to 33%), cadinol (approximately 5%), and epicubenol, while phenols such as guaiacol account for approximately 12% of the composition. Hydrocarbons like alpha-pinene (7–12%) also contribute notably.

Major phenolic constituents include creosol, guaiacol, phenol, o-cresol, and p-cresol. The oil also contains etheric oils and triterpenes.

3.2 Chemical Composition of Leaf and Berry Essential Oils

The leaf oils of J. oxycedrus ssp. badia are mainly composed of α-pinene (40–57%) and manoyl oxide (5–10%). The (unripe) berry oils are dominated by α-pinene (65%) with moderate amounts of myrcene, limonene, germacrene D, or γ-muurolene.

Essential oil content in dried juniper leaves varies from 0.06% to 0.24%. Fifty-one EO constituents have been identified, belonging to monoterpenes, sesquiterpenes, and diterpenes.

In a 2024 study using Sardinian J. oxycedrus, the main constituents of the extracted EO were α-pinene (>50%), β-pinene (>10%), and limonene (>10%).

Various molecules have been discovered and separated from Juniperus oxycedrus extracts and essential oils. Identified phytochemicals include alpha-pinene, beta-myrcene, beta-pinene, d-limonene, and camphene.

3.3 Additional Phytochemical Classes

Phytochemical investigation of polar extract from Juniperus oxycedrus ssp. oxycedrus berries led to the isolation of one new monoterpene glucoside: (3R,6E)-3,7-dimethyl-8-hydroxy-6-octenoic acid 8-O-β-d-glucopyranoside, along with seven known components. Structures were established by extensive 1D and 2D NMR and ESI-MS studies.

Studies on J. oxycedrus wood tar reveal a strong presence of phenolic, tannin, and flavonoid compounds, which significantly contribute to antioxidant activity.

3.4 Mechanisms of Action

In regard to pharmacology, cade oil has been reported to have keratolytic and antipruritic properties, and antimicrobial activities in vitro. The oil contains phenols, which are believed to be the most toxic components.

Methanol and dichloromethane extracts of leaves and stems of J. oxycedrus ssp. oxycedrus from Spain have been found to reduce the blood pressure of normotensive rats, to inhibit the response to histamine, serotonin and acetylcholine, and to exhibit significant anti-inflammatory activity.

The essential oil and extracts of J. oxycedrus exhibit strong antimicrobial and antifungal activity against various pathogens, including Staphylococcus aureus, Candida albicans, and dermatophytes, due to the high content of phenolic compounds such as guaiacol and creosol.

4. Scientific Evidence by Area of Use

4.1 Dermatological Applications (Eczema, Psoriasis, Dandruff)

Cade oil has been widely employed in human and veterinary dermatology to treat chronic eczema and other skin diseases. Uses in skin medicine include treating psoriasis, dandruff, eczema itching, and pediculicidal/scabicidal activity (killing lice and scabies).

The clinical evidence for cade oil in dermatological conditions is predominantly pre-clinical and historical. Laboratory studies show that cade extracts can kill bacteria in test tubes, and animal experiments suggest it reduces pain and inflammation. However, there is not enough clinical research in humans to confirm these effects translate reliably to people.

Preparations of coal-tar and juniper tar (cade oil) that are used in the treatment of psoriasis are known to contain numerous potentially carcinogenic polycyclic aromatic hydrocarbons (PAH). Evidence of covalent binding to DNA by components of these mixtures was sought in human skin biopsy samples from 12 psoriasis patients receiving therapy with these agents. This study (published 1990, PubMed ID 2299199) found evidence of DNA adduct formation, raising genotoxic concerns with the crude tar preparation. It does not establish efficacy, and the clinical evidence for the dermatological use of cade oil in controlled human trials remains limited.

Clinical tests showed no evidence of irritation or sensitization with any of the tested oils, but some evidence of sensitization to the tar. These data were not considered sufficient to assess the safety of these ingredients.

Overall evidence strength for dermatological use: Traditional use is well-documented; pharmacological activity has been demonstrated in vitro. Controlled human clinical trials specifically for cade oil are lacking. No randomized controlled trials have been identified in major databases.

4.2 Antimicrobial and Antifungal Activity

Several extracts of leaves, resins, barks, and fruits of J. oxycedrus ssp. oxycedrus from Turkey were found to inhibit the growth of several bacteria, but did not show antifungal effects. However, the essential oil of the heartwood of the same subspecies from Italy did show activity against gram-positive bacteria and most of the screened blastomycetes.

Juniperus oxycedrus tar showed strong DPPH antioxidant activity with an IC₅₀ of 11.147 ± 2.13 µg/mL. Both J. oxycedrus and J. phoenicea extracts demonstrated notable antimicrobial activity at 200 mg/mL concentration, particularly against Staphylococcus aureus and Escherichia coli, with inhibition zones of 12–14 mm and 11–12 mm, respectively.

A 2024 study demonstrated that juniper EO microneedle delivery systems (MNDs) were able to inhibit bacterial and fungal proliferation in in vitro and in vivo models, thus preventing microbial infection at the site of wound infection. It was also demonstrated that treatment with juniper EO MNDs improved wound healing with quick tissue recovery. The investigators noted that more studies are needed, particularly in humans, to confirm the efficacy of this technique in infected-wound healing.

Overall evidence strength: Antimicrobial activity against relevant pathogens is consistently demonstrated in vitro across multiple studies. Efficacy in human clinical settings has not been established in controlled trials.

4.3 Wound Healing and Anti-inflammatory Activity

A published study in PMC (PMC3175711) evaluated the wound healing and anti-inflammatory properties of essential oils from Turkish Juniperus species in animal models. Essential oils obtained from cones of Cupressus and berries of Juniperus were evaluated for wound healing and anti-inflammatory effects. In vivo wound healing activity was evaluated by linear incision and circular excision experimental wound models, assessment of hydroxyproline content, and histopathological analysis. The healing potential was comparatively assessed with a reference ointment Madecassol. The essential oils of J. oxycedrus subsp. oxycedrus and J. phoenicea demonstrated the highest activities, while the rest of the species did not show any significant wound healing effect. The experimental study revealed that J. oxycedrus subsp. oxycedrus displays remarkable wound healing and anti-inflammatory activities, which support the folkloric use of the plants.

Methanol and dichloromethane extracts of leaves and stems have been found to reduce blood pressure in normotensive rats, to inhibit the response to histamine, serotonin, and acetylcholine, and to possess analgesic properties.

Overall evidence strength: Wound healing and anti-inflammatory activity demonstrated in preclinical (animal) models. No human clinical trials identified.

4.4 Antidiabetic Activity

Loizzo et al. (2007) evaluated the in vitro hypoglycemic activity of J. oxycedrus ssp. oxycedrus berry and wood essential oils by the inhibition of α-amylase; the wood oil was found to be active. Subsequent research investigated in vivo antidiabetic activities of J. oxycedrus ssp. oxycedrus leaf and fruit extracts in detail and identified their active components.

Overall evidence strength: Preliminary; limited to in vitro enzyme inhibition studies and animal models. No human clinical evidence.

4.5 Antioxidant Activity

Juniperus oxycedrus extracts showed interesting pharmacological properties as they demonstrated antioxidant, antidiabetic, antimicrobial, antiviral, anti-cholinesterase, anti-tyrosinase, anti-proliferative, and cytotoxic properties in a 2024 review covering literature from 2000 to 2024.

Antioxidant activity of J. oxycedrus tar has been evaluated using DPPH, ABTS, and FRAP assays, while antimicrobial activity was tested against a range of pathogenic bacteria and fungi. This research provides the first comparative biological evaluation of Moroccan Juniperus oxycedrus tar and demonstrates its potential application as a source of natural antioxidants and antimicrobial agents.

Overall evidence strength: In vitro antioxidant activity is documented via standard assays. No human trials on antioxidant endpoints.

4.6 Anticancer / Cytotoxic Activity

Shikimic acid isolated from J. oxycedrus berries showed anti-inflammatory effects on MCF-7 cells (a human breast cancer cell line) in vitro.

Juniperus oxycedrus essential oil exhibited a tyrosinase suppression of 39% and an acetylcholinesterase inhibition rate of 65.88% in reported assays. A 2024 systematic review (Springer, Phytochemistry Reviews) covering 70 included studies reported bioactivities including anti-inflammatory, anti-diabetic, antibacterial, antifungal, antiviral, cytotoxic and anti-proliferative, cholinesterase enzyme inhibitory, and wound healing activity for the fruit, leaves, and essential oil of J. oxycedrus.

Overall evidence strength: All cytotoxic and antiproliferative data are from in vitro (cell line) studies. No clinical evidence in humans exists for anticancer application.

4.7 Cholinesterase Inhibition (Potential Neuroprotective Interest)

The essential oil of J. oxycedrus exhibited an acetylcholinesterase inhibition rate of 65.88% in reported in vitro assays. This has attracted research interest given the relevance of acetylcholinesterase inhibition to Alzheimer's disease models, but no human clinical studies have been conducted in this area for cade juniper.

5. Body Systems and Health Areas of Association

• Integumentary system (skin and scalp): Cade oil is used medicinally, particularly for dermatitis. Traditional and industrial applications include eczema, psoriasis, dandruff, pediculosis (lice), and wound care.
• Antimicrobial / Immune support: Pharmacological activities documented include antiseptic, antimicrobial, diuretic, carminative, and antidiabetic properties.
• Respiratory system: Leaves are used in infusion to treat asthma and cough in traditional Moroccan and Algerian medicine.
• Gastrointestinal system: Cade oil has been used for its antidiarrheal properties in Moroccan traditional medicine.
• Metabolic/Endocrine: Traditional use for hyperglycemia and obesity is documented in ethnobotanical literature, with supporting in vitro α-amylase inhibition data.
• Musculoskeletal/Pain: Historically recognized for its pain-relieving (analgesic) and anti-itch (antipruritic) properties.
• Veterinary: Cade oil has been widely employed in veterinary dermatology.

6. Dosage Forms and Reported Dosages

There are no standardized clinical dosing protocols for cade oil established by regulatory pharmacopeias or derived from controlled human trials. Available information derives from traditional practice reports and in vitro research design:

• Topical application (traditional): Cade oil was applied sometimes at full strength, sometimes diluted with a bland oil, well rubbed into the affected parts with the fingers or with a cloth, and was also made into ointments and soaps.
• In vitro antimicrobial testing: Notable antimicrobial activity against Staphylococcus aureus and E. coli was demonstrated at the concentration of 200 mg/mL.
• In vitro antioxidant assay: J. oxycedrus tar showed DPPH antioxidant activity with an IC₅₀ of 11.147 ± 2.13 µg/mL.
• In vitro hypoglycemic assay: Wood oil of J. oxycedrus was found active in α-amylase inhibition in a study by Loizzo et al. (2007), though specific concentrations used are not reproduced here.
• EO microneedle research (preclinical, 2024): The main constituents of the EO used were α-pinene (>50%), β-pinene (>10%), and limonene (>10%).
• Parts used in traditional medicine: Parts used include the wood, fruits (berries), and oil.

No controlled human clinical trial has established a safe and effective dosing range for any cade oil preparation.

7. Safety Considerations and Toxicity

7.1 Phenol-Mediated Systemic Toxicity

The data on the adverse effects of cade oil suggests that it could have life-threatening effects which can occur following topical exposure, ingestion, or inhalation. Cade oil contains toxic phenols including guaiacol and cresol, which can cause serious side effects across various organ systems, including renal, hepatic, cardiac, pulmonary, neurological, gastrointestinal, dermatological, hematological, and metabolic.

Its renal and hepatic toxicity is well known. Exposure to cade oil can occur by all routes, but skin contact and ingestion can lead to significant systemic toxicity. The involvement of cade oil should be considered in patients with multi-organ symptoms.

7.2 Moroccan Pharmacovigilance Database Evidence

An analysis of a Moroccan pharmacovigilance herbal products database from January 1, 2004 to December 31, 2012 found that 30 (2.4%) of 1,251 reported adverse events associated with herbal products were related to cade oil. Reported cases were mainly due to topical application (60%), oral ingestion (36.7%), or nasal application (3.3%). The reported adverse effects involved many organs, but renal disorders were the most common.

7.3 Severe Cases in Infants and Children

One documented case reported a previously healthy newborn treated with a topical application of Juniperus oxycedrus for atopic dermatosis. The poisoning caused convulsions, collapse, acute pulmonary oedema, renal failure, and hepatotoxicity. The newborn survived after supportive and symptomatic treatment.

Fatal poisonings have been reported in four infants. Three cases involved previously healthy babies treated with topical application of Juniperus oxycedrus for diarrhea, vomiting, and fever; one case involved a baby who was given three spoonfuls of cade oil to treat diarrhea.

Severe systemic toxicity was reported after local administration of cade oil in a 12-month-old infant. The infant was hospitalized in the pediatric resuscitation department for respiratory and neurological distress following topical application to the wrists, elbows, forehead, and head.

7.4 Genotoxicity and Carcinogenic Concerns

Juniperus Oxycedrus Tar was genotoxic in several assays according to the Cosmetic Ingredient Review (CIR) safety assessment. Wood tar and wood tar preparations contain genotoxic polycyclic aromatic hydrocarbons. Moreover, phenol, a constituent, has been proposed to be classified as a category 3 mutagen.

The essential oil and oleoresins removed from Juniperus oxycedrus are toxic at high doses and with prolonged application, carrying a carcinogenic risk.

Rectification of crude cade oil is specifically intended to remove carcinogenic impurities such as polynuclear hydrocarbons, ensuring safer use in various applications. This rectification is critical to distinguish pharmaceutical-grade cade oil from the crude tar.

7.5 Regulatory Status and Insufficient Safety Assessment

Clinical tests showed no evidence of irritation or sensitization with any of the tested oils, but some evidence of sensitization to the tar. These data were not considered sufficient to assess the safety of these ingredients by the CIR Expert Panel.

In December 1997, the CIR Expert Panel reached a tentative conclusion that the available data were insufficient to support the safety of these ingredients.

7.6 Skin Sensitization

Cade oil has, on rare occasions, caused severe allergic reactions in infants. The CIR assessment found some evidence of sensitization with the crude tar formulation.

7.7 Oral Use Contraindicated

The data on the adverse effects of cade oil suggests that it could have life-threatening effects. Cade oil is a dark, faintly aromatic oil which is distilled from the branches and wood of Juniperus oxycedrus. Although this oil is known to have toxic effects related to its content of phenols, cade oil continues to be used in folk medicine.

8. Evidence Quality Summary

The body of research on cade juniper and its principal preparation, cade oil, is characterized primarily by ethnobotanical documentation, in vitro laboratory studies, and animal experiments. The 2024 systematic review in Phytochemistry Reviews (Springer) providing an updated overview of J. oxycedrus fruit, leaves, and EO chemistry through a systematic search in Scopus, Web of Science, and PubMed included 70 studies after application of inclusion/exclusion criteria. The review identified anti-inflammatory, anti-diabetic, antibacterial, antifungal, antiviral, cytotoxic and anti-proliferative, cholinesterase enzyme inhibitory, and wound healing activity among the reported bioactivities. However, no large, randomized, double-blind, placebo-controlled clinical trials have been identified for any indication. The safety database, particularly the Moroccan pharmacovigilance data and published case reports, documents significant real-world toxicity, especially in pediatric populations and with unsupervised use.

References

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