Carlina

Carlina (Carlina acaulis L.): A Comprehensive Reference

1. Identity and Botanical Classification

Scientific name: Carlina acaulis L. (also written as Carlina acaulis subsp. acaulis and Carlina acaulis subsp. caulescens). Synonyms / common names: Stemless carline thistle, silver thistle, white carline thistle, Carlinae radix (the pharmacopoeial name for its root). In traditional vernacular it has also been called "nine forces" (Dziewięćsił) in Polish culture, and Chamaeleon albus in ancient Greco-Roman texts.

Carlina acaulis L. belongs to the Asteraceae (Compositae) family and is a perennial herb native to the Alps, which has a long history as a food and traditional remedy, being one of the most important medicinal plants in Europe. The genus Carlina (Asteraceae) comprises approximately 30 plant species growing in Europe and Asia.

C. acaulis belongs to the Asteraceae family, specifically the Cardueae tribe and Carlininae subtribe. The first detailed taxonomy of the plant can be found in Flora Europea, in which C. acaulis is classified in the genus Carlina, together with almost 30 other species, in the subgenus Carlina. Two subspecies can be distinguished: the stemless subspecies and another form. Carlina acaulis L. is a monocarpic perennial from the Asteraceae family occurring in South and Central Europe. It grows mainly on xerothermic and calcareous grasslands in the mountains, while its occurrence in lowland areas is rare. The plant has a thick and fleshy taproot. The lanceolate, margin spinulose leaves grow in a basal rosette. Tubular flowers, collected in silvery-white florets with a diameter from 7 to 15 cm, appear from August onwards.

Other medicinally studied species within the genus include Carlina acanthifolia, Carlina vulgaris, and Carlina corymbosa, though C. acaulis is by far the most extensively researched and the species most commonly referenced in pharmacopoeial and regulatory contexts.

Common Forms and Preparations

• Root (Carlinae radix): The primary pharmacopoeial material, used fresh, dried, or as a powder, decoction, or hydroalcoholic extract.
• Root essential oil (EO): Obtained by hydrodistillation; the essential oil obtained by hydrodistillation is a yellowish liquid with a strong aroma, and its content in C. acaulis roots is 1–2%.
• Herbal teas and decoctions: Traditional preparations using the dried root. Historical folk records indicate preparation of a decoction using 2 g of root in 100 mL of water, taken in 2–3 cups per day.
• Tinctures and hydroalcoholic extracts: Used in modern herbal medicine.
• Topical preparations: Applied externally for skin conditions.
• Cypsela (fruit/seed): The cypsela has been shown to be a rich source of macro- and microelements, vegetable oil (25%), and α-tocopherol (approximately 2 g/kg of oil) as well as protein.

2. Regulatory Status

The use of C. acaulis EO has not been associated with toxicity phenomena, and it has been included, along with the root from which it is obtained, in the Italian list of botanical products to be used in food supplements and on the BELFRIT list (Cousyn et al., 2013). Carlina acaulis root and its EO are nowadays included in the Italian list of botanicals to be used in food supplements as well as in the BELFRIT list, where they are indicated as diuretic, diaphoretic, carminative, and eupeptic substances.

The BELFRIT (Belgium, France, Italy) project represents a first step toward harmonization of botanical substances permitted in food supplements across the European Union. The result is a list of about 1000 herbal substances, assessed and approved by a scientific committee; the list is already in effect in Italy and Belgium, while France adopted a comparable list of approved botanicals, though the conclusions are not legally binding for any EU country.

3. Historical and Traditional Use

Ancient and Classical Antiquity

Plants from the genus Carlina were already described by Theophrastus of Eresus, Dioscorides, Pliny the Elder, and Galen of Pergamum. In their works, the plants are referred to as Chamaeleon niger and Chamaeleon albus. The citation of Carlina by all four of the foundational ancient authorities of natural medicine demonstrates that the plant's medicinal properties were recognized from at least the 3rd century BCE onward in the Mediterranean and Near Eastern traditions.

Medieval and Renaissance Europe

Carlinae radix was still featured in Renaissance botanical books and in official pharmacopoeias, but disappeared from the scene in the 19th century. Carlina acaulis L. was included in the Bavarian Pharmacopoeia (Ph. Bav.), cited alongside other official herbal monographs of the era.

Among Polish highland communities (Gorale), Carlina acaulis was used in mouth rinsing as a gum-strengthening agent, and several different plants had the dialect name "nine forces" but the most famous one was carline thistle (Carlina acaulis).

Traditional European Folk Medicine

Carlina acaulis L. was widely used as medicine, especially in Germany and Poland. The plant root was applied to treat various skin diseases and as a diaphoretic, diuretic, and anthelmintic agent. At the end of the 19th century, the medicinal use of the plant ceased, though C. acaulis roots are still used in folk medicine, especially in rural areas of the Balkans where the plant grows in the wild.

Various species of the Carlina genus, including C. acaulis, C. acanthifolia, C. utzka, and C. corymbosa, are still used in traditional medicine in Spain, Italy, Hungary, Poland, Lithuania, and the Balkan countries, mostly for their cholagogic, diuretic, antibiotic, and cleansing effects.

Herb extracts are applied externally to facilitate healing of skin lesions.

The principal traditional indications documented across these cultures include:

• Digestive system: Traditionally employed in remedies to combat digestive disorders, including bloating, indigestion, and stomach cramps. The root was often prepared as a decoction or infusion, believed to stimulate appetite and support overall gastrointestinal health.
• Diaphoretic use: It has a long tradition in herbal medicine and is used above all as a diaphoretic (to promote sweating) in cases of fever, cold, and flu. Another common use is as a diuretic.
• Skin diseases: Reported uses include treatment of skin diseases, acne, eczema, and ulcers.
• Anthelmintic: Used as a remedy against intestinal worms, documented especially in German and Polish traditional pharmacopoeia.
• Polish ethnobotany: Polish inhabitants especially valued carline thistle (Carlina acaulis L.) among their medicinal plants.

There are several reports indicating that the roots of Carlina acaulis L. used to be commonly applied as a treatment measure in skin diseases and as an antiparasitic agent, starting from antiquity to the 19th century; however, nowadays, it has lost its formal pharmacopoeial importance.

4. Key Phytochemical Constituents

The present-day information on the phytochemistry and pharmacological activity of these plants is limited. There are some data on the occurrence of common plant ingredients such as essential oil, flavonoids, phenolic acids, triterpenes, inulin, and fatty acids.

Carlina Oxide (the Dominant Active Compound)

Carlina oxide, 2-(3-phenylprop-1-ynyl)furan, is a natural polyacetylene that constitutes up to 90–99% of the essential oil. From the analysis of the EO composition, the main constituent is the polyacetylene 2-(3-phenylprop-1-yn-1-yl)furan, also known as carlina oxide (molecular formula: C₁₃H₁₀O; molecular weight: 182), which was isolated in 1889, becoming one of the oldest known members of the polyacetylenes family. It is chemically classified as an aromatic polyacetylene featuring a furan ring linked via an alkyne bond to a phenylpropyl chain, a structure unique within the botanical world in its extremely high fractional dominance within an essential oil.

Inulin

An earlier study reported that Carlina acaulis roots contained approximately 20% of inulin. Another study suggested that inulin is the main compound of Carlina spp., comprising 18–20%. Inulin is a fructan-type polysaccharide that functions as a prebiotic, selectively stimulating the growth of beneficial intestinal bacteria.

Flavonoids

In the herb, flavonoids including orientin, homoorientin, isoschaftoside, vitexin, apigenin 7-O-glucoside, and apigenin have been identified. These C-glycosyl and O-glycosyl flavones are associated with antioxidant, anti-inflammatory, and antispasmodic activities.

Chlorogenic Acids (Phenolic Acids)

The species is rich in chlorogenic acids and C-glycosides of luteolin and apigenin. The total amount of chlorogenic acids in the root has been measured at 12.6 mg/g. Chlorogenic acids are esters of caffeic acid with quinic acid and are among the most studied dietary antioxidants.

Pentacyclic Triterpenes

Pentacyclic triterpenes identified include lupeol, lupeol acetate, α-amyrin, β-amyrin, β-amyrin acetate, betulinic acid, oleanolic acid, and ursolic acid. The main triterpenes found in C. acaulis are pentacyclic triterpenes, mainly oleanolic and ursolic acid, and the amount of these metabolites depends on the way C. acaulis is cultivated.

Other Identified Constituents

From the roots of C. acaulis, different constituents have been extracted and characterized: inulin, essential oil, tannins, triterpenes, and chlorogenic acids. The cypsela (achene/fruit) has additionally been characterized as a source of unsaturated fatty acids, essential amino acids, tocopherols, and mineral elements.

5. Mechanisms of Action

Antimicrobial Mechanism of Carlina Oxide

The essential oil of Carlina acaulis L. is mainly characterized by the polyacetylene carlina oxide, which has antimicrobial properties. The structural features of carlina oxide — specifically its conjugated triple bond in proximity to an aromatic furan ring — are understood to enable intercalation with microbial cell membranes and disruption of membrane integrity. Results from in vitro studies showed that the EO and carlina oxide are active against Gram-positive bacteria, with a more marked activity for carlina oxide. Tests showed a complete EO and carlina oxide inefficacy against Gram-negative species, which is consistent with the protective outer membrane of Gram-negative organisms limiting access to the cytoplasmic membrane.

Cytotoxic / Antiproliferative Mechanism

Carlina oxide (50 µg/mL) decreased the expression of AKT and extracellular signal-regulated kinase 1/2 (ERK1/2), the key signaling nodes driving proliferation and cell survival. In vitro studies showed a toxic effect of carlina oxide, as demonstrated by an induction of apoptosis and necrosis in both normal and melanoma cells. Decreased expression of AKT kinase and ERK1/2 was noted in the UACC-647 melanoma cell line. It was also observed that carlina oxide modified the expression of programmed cell death-ligand 1 (PD-L1) in tested cell lines. This suggests potential modulation of immune checkpoint pathways, although this has been studied only in cell culture models.

Antioxidant Mechanism

All investigated Carlina extracts showed moderate antioxidant activity. Total antioxidant activity (TAA) was in correlation with total phenolics content (TPC), but lower than the activity of L-ascorbic acid used as standard (7.41 µmol Fe²⁺/mg). Quenching of DPPH radical was concentration-dependent. Extracts of Carlina herbs were more potent scavengers of DPPH radical than the extracts of the roots. This difference is attributed to the higher flavonoid and phenolic acid content in aerial parts compared to the root.

Triterpene Mechanisms

The presence of phenolic acids and triterpenes, especially ursolic and oleanolic acids, may explain some of the antitumorigenic properties of the leaf extracts, as well as rationalize the application of Carlina species in traditional anticancer treatments. There are numerous reports on antiproliferative and proapoptotic properties of ursolic and oleanolic acids. In studies on the human melanoma M4Beu cell line, it was demonstrated that ursolic acid exerted a significant antiproliferative effect associated with caspase-3 activation. It was shown that ursolic acid induced apoptosis of melanoma MM200, Mel-RM, Me4405, and A375 cell lines.

6. Scientific Evidence by Area of Use

6.1 Antimicrobial Activity

Evidence level: Preclinical (in vitro); no human clinical trials.

Herrmann et al. (Planta Medica, 2011) confirmed that Carlina acaulis has a long history of medicinal use in Europe due to its antimicrobial properties. The strong activity of carlina oxide, the main compound of the essential oil of C. acaulis, against two MRSA strains, Streptococcus pyogenes, Pseudomonas aeruginosa, Candida albicans, and C. glabrata was confirmed. A strong and selective activity against Trypanosoma brucei brucei with an IC₅₀ of 1.0 µg/mL and a selectivity index of 446 compared to human HeLa cells was recorded. The selective toxicity of carlina oxide makes it a promising lead compound for the development of drugs to treat African trypanosomiasis and multiresistant Gram-positive bacteria.

The EO and carlina oxide showed encouraging bioactivity on a variety of bacteria and fungi, including Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris, Candida albicans, and C. glabrata.

A 2021 study published in Antibiotics (Basel) evaluated a nanoemulsion formulation: The NE containing C. acaulis EO was prepared with the high-pressure homogenization method, and the MIC was determined against several bacterial and fungal strains for all the C. acaulis-derived products, which were active versus all screened Gram-positive bacterial strains and also on all fungal strains with low MIC values. For yeast, the EO and carlina oxide showed good MIC values. The EO and carlina oxide were active against Gram-positive bacteria with values ranging between 2.7 and 10.9 mg/mL and 0.33 and 5.35 mg/mL, respectively.

Limitations: All antimicrobial data is from in vitro (laboratory) models. No clinical trials in humans have been conducted to evaluate the efficacy of carlina oxide or C. acaulis extracts as antimicrobial or antitrypanosomal agents. Translation from in vitro MIC values to in vivo efficacy involves significant pharmacokinetic and bioavailability uncertainties.

6.2 Antioxidant Activity

Evidence level: Preclinical (in vitro); no human clinical trials.

A 2017 study published in Oxidative Medicine and Cellular Longevity examined three populations of Carlina vulgaris L.: Methanol extracts from three populations of Carlina vulgaris L. were examined for chlorogenic acid content, mineral content, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity. Results demonstrated significant but concentration-dependent DPPH radical scavenging activity, correlated with phenolic and flavonoid content. Herb extracts were consistently more potent antioxidants than root extracts in comparative studies, due to higher phenolic content in above-ground parts.

Limitations: All antioxidant data is from in vitro assays such as DPPH, FRAP, and TBARS. These assays measure chemical reducing capacity under artificial conditions and do not reliably predict bioavailable antioxidant effects in humans.

6.3 Antiproliferative / Anticancer Activity

Evidence level: Preclinical (in vitro only); no human clinical trials.

A study published in Frontiers in Pharmacology (2017) evaluated in vitro antiproliferative activity: Anti-tumor properties of the extracts were explored using a tetrazolium-based cell viability assay and flow cytometric apoptosis analysis, followed by immunodetection of phosphoactive ERK1/2 in UACC-903, C32, and UACC-647 human melanoma cell lines. Normal human fibroblasts were used as a control. Leaf extracts inhibited the viability of all tested melanoma cell lines in a dose-dependent fashion while the fibroblasts were less sensitive to such extract.

The extracts from the leaves and roots were analyzed by HPLC, and the analysis showed the presence of triterpenes and phenolic acids as the main extract components. The research demonstrated that the extracts from the leaves of the plants were cytotoxic against the human melanoma line and induced apoptosis of the cells. The triterpene fraction present in the tested extracts may be responsible for this activity.

Leaf extracts from C. acaulis subsp. caulescens (100 µg/mL) inhibited proliferatory ERK1/2 in UACC-903 and C32 cells, as demonstrated by the decrease in ERK1/2 phosphorylation.

A separate toxicology study (Wnorowski et al., Toxins, 2020) found that: C. acaulis root extracts devoid of carlina oxide displayed no cytotoxicity to human cells in vitro. Additionally, carlina oxide-free extracts significantly stimulated the proliferation of skin cells of human origin. This important finding indicates that the biological activity profile of the whole plant is more nuanced than that of its isolated principal volatile constituent, with implications for the type of preparation used medicinally.

Limitations: All anticancer data is from cell culture models (in vitro). No animal models or human clinical trials have been published. Translation from cell culture cytotoxicity to clinical anticancer efficacy is highly uncertain, and the selectivity index (cancer cells versus normal cells) requires further characterization across a broader panel of cell types.

6.4 Anti-Inflammatory Activity

Evidence level: Preclinical (in vitro and limited animal); no human clinical trials.

Antimicrobial activity has been proven for the oil isolated from the root of C. acanthifolia, along with other pharmacological effects including anti-inflammatory, anti-ulcer, and antioxidant activity. Studies examining hydromethanolic extracts of C. acaulis and C. acanthifolia roots and herbs demonstrated in vitro anti-inflammatory activity, assessed in standard biochemical screening assays.

Limitations: Anti-inflammatory data from Carlina species derives from in vitro enzyme inhibition assays and limited preclinical testing. No randomized controlled trials in humans have investigated the anti-inflammatory effects of any Carlina preparation.

6.5 Digestive and Cholagogic Activity

Evidence level: Traditional use supported by plausible phytochemical mechanisms; no clinical trials.

The Italian list of botanicals used in food supplements and the BELFRIT list include C. acaulis root and its EO, described as diaphoretic, eupeptic, diuretic, and carminative. The bitter principle and essential oil constituents are pharmacognostically consistent with digestive stimulant activity — a class of phytochemicals well-recognized for their capacity to stimulate bile secretion (cholagogic effect) and gastric juice production (eupeptic effect). However, these mechanisms have not been specifically measured in controlled human trials for Carlina.

6.6 Antitrypanosomal Activity

Evidence level: Preclinical (in vitro); no human clinical trials.

The study of Herrmann et al. (2011) reported the antitrypanosomal property of C. acaulis hexane extract and carlina oxide against Trypanosoma brucei brucei. A strong and selective activity against Trypanosoma brucei brucei with an IC₅₀ of 1.0 µg/mL and a selectivity index of 446 compared to human HeLa cells was recorded. The selective toxicity of carlina oxide makes it a promising lead compound for the development of drugs to treat African trypanosomiasis and multiresistant Gram-positive bacteria.

Limitations: All antitrypanosomal data is from cell culture. No animal efficacy models or human studies have been published. While the selectivity index is favorable, the compound's in vivo pharmacokinetics, bioavailability, and potential systemic toxicity at therapeutic concentrations remain unstudied in mammalian models relevant to human use.

7. Body Systems and Health Areas Associated with Carlina

• Gastrointestinal system: Diaphoretic, carminative, eupeptic (digestive stimulant), and cholagogic indications; traditional use for gastritis, indigestion, and bloating. The inulin content additionally positions the root as a potential prebiotic substrate for gut microbiota.
• Renal/urinary system: Traditional diuretic use, listed as such in the BELFRIT regulatory classification.
• Integumentary system (skin): External application for eczema, acne, ulcers, and other skin disorders documented across multiple European ethnobotanical traditions. In vitro evidence of antiproliferative activity against melanoma cell lines.
• Immune/antimicrobial system: In vitro activity against a broad spectrum of Gram-positive bacteria (including MRSA), selected Gram-negative bacteria, fungi (Candida spp.), and parasites (trypanosomes).
• Thermoregulatory system: Traditional use as a diaphoretic for fever management in the context of colds and influenza.
• Antiparasitic: Traditional anthelmintic use documented in German and Polish pharmacopoeial history; in vitro antitrypanosomal activity confirmed in modern laboratory studies.

8. Dosage Forms and Reported Dosages

No standardized human clinical dosage has been established for any preparation of Carlina acaulis, as no formal clinical dose-finding trials have been published. The following dosages appear in traditional-use and ethnobotanical literature only:

• Decoction (traditional): Historical folk sources describe preparation of a decoction using 2 g of dried root in 100 mL of water, taken as 2–3 cups per day, for promotion of sweating, digestive support, and diuresis.
• Essential oil: The EO is included in the BELFRIT food supplement list without a specified dose ceiling in the published regulatory text. The concentration of carlina oxide in such preparations is a critical safety variable (see Section 9).
• Hydroalcoholic extract (veterinary reference): The European Agency for the Evaluation of Medicinal Products declared that the root hydroalcoholic extract is a safe treatment for animals.
• In vitro/preclinical concentrations (not for human dosing): Studies used carlina oxide at concentrations of 0.25–50 µg/mL for antimicrobial testing and up to 300 µg/mL for antiproliferative assays; these in vitro concentrations should not be extrapolated to human dosing guidance.

The appropriate dose of carlina depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for carlina.

9. Safety Considerations

Toxicity of Carlina Oxide

In vitro studies showed a toxic effect of carlina oxide, as demonstrated by an induction of apoptosis and necrosis in both normal and melanoma cells. Carlina oxide exhibited high in vivo toxicity, with LC₅₀ = 10.13 µg/mL upon 96 hours of exposure in the zebrafish embryo toxicity test (ZFET).

Recent studies have pointed out that the C. acaulis EO is cytotoxic to fibroblasts and keratinocytes and mildly toxic to rats. A higher administration of 1000 mg/kg led to the development of neurological, gastric, and hepatic toxicity. However, the EO showed a significant safety profile since the dosage in the insecticidal formulations would, in any event, be lower than those tested.

The relationship between preparations with and without carlina oxide is pharmacologically important: C. acaulis root extracts devoid of carlina oxide displayed no cytotoxicity to human cells in vitro. Additionally, carlina oxide-free extracts significantly stimulated the proliferation of skin cells of human origin. This finding implies that the safety profile of Carlina preparations depends critically on the carlina oxide content, which itself depends on the preparation method and the plant part used.

Concerning cytotoxicity selectivity among cell lines, Herrmann and co-workers studied the cytotoxicity of carlina oxide in the HeLa cervical cancer cell line. HeLa cells showed striking resistance to carlina oxide. The cells displayed no change in viability at around 50 µg/mL of carlina oxide, which is comparable to C32 cells in another study. However, HeLa cells survived the exposure of much higher doses of carlina oxide, yielding an LC₅₀ value of 446 µg/mL. This variability across cell lines underscores the difficulty of predicting in vivo toxicity.

Researchers have highlighted the dual-use tension of the EO: the EO can be used to develop new insecticides; restriction of its employment as food may be considered. Findings encourage food safety authorities to perform a full toxicological assessment for possible restrictions at the food level.

Heavy Metal Accumulation

Carlina vulgaris has been collected from both natural nonmetallicolous habitats and from metallicolous populations at waste heaps from former open-cast mining. The level of Zn, Pb, Cd, Fe, Ni, and Mn was significantly higher in the root and leaves of plants growing on contaminated soils compared to those from uncontaminated habitats. This is a source-specific safety concern: Carlina plants growing near mining or smelting waste sites may concentrate heavy metals and should not be used as herbal material.

Allergenicity

Carlina may cause an allergic reaction in people who are sensitive to the Asteraceae/Compositae plant family. Members of this family include ragweed, chrysanthemums, marigolds, daisies, and many others. Cross-reactivity with other Asteraceae allergens is a recognized pharmacological risk for atopic individuals, consistent with the well-documented Compositae allergy syndrome.

Pregnancy and Lactation

No safety data from controlled human studies exists for use during pregnancy or lactation. The traditional anthelmintic and diaphoretic uses of the plant, combined with the known cytotoxicity of carlina oxide, indicate that use during pregnancy cannot be considered safe based on available evidence.

Overall Evidence Gap

Preliminary in vitro and animal studies suggest that Carlina extracts may offer protective effects against certain pathogens and oxidative stress, supporting its traditional uses. However, robust clinical trials evaluating the efficacy and safety of Carlina in humans remain limited. Currently, numerous studies are being conducted assessing the possibility of reintroducing C. acaulis-derived extracts to phytotherapy. Determining the safety profile of the main constituents of the plant material is crucial for achieving this goal.

10. Summary of Evidence Strength

• Antimicrobial (in vitro): Consistent, replicated, and well-characterized across multiple laboratories. Strong in vitro evidence. No human data.
• Antitrypanosomal (in vitro): Single key study with excellent selectivity index; requires in vivo confirmation.
• Antiproliferative/anticancer (in vitro): Preliminary; restricted to melanoma cell lines; triterpene fraction likely responsible; requires animal and human studies.
• Antioxidant (in vitro): Moderate and reproducible; herb extracts superior to root extracts; no human clinical relevance established.
• Anti-inflammatory (in vitro/preclinical): Preliminary; mechanistic basis plausible via phenolics and triterpenes; no human data.
• Digestive/diuretic/diaphoretic: Based on traditional use and pharmacopoeial listing; phytochemically plausible; no controlled human trials.
• Safety: Mixed — the EO and its principal constituent (carlina oxide) exhibit genuine cytotoxic and in vivo toxicity at higher concentrations; extracts devoid of EO have shown a favorable safety profile in vitro. Full clinical toxicological assessment has not been performed.

References

• Strzemski M. et al. (2019). Historical and traditional medical applications of Carlina acaulis L. — A critical ethnopharmacological review. Journal of Ethnopharmacology. ScienceDirect.
• PRIME PubMed — Historical and traditional medical applications of Carlina acaulis L. (PubMed abstract, PMID 30948315).
• Carlina acaulis L. (Asteraceae): biology, phytochemistry, and application as a promising source of effective green insecticides and acaricides. Industrial Crops and Products, 2022. ScienceDirect.
• Strzemski M. et al. (2017). In Vitro Antiproliferative Activity of Extracts of Carlina acaulis subsp. caulescens and Carlina acanthifolia subsp. utzka. Frontiers in Pharmacology.
• PMC — In Vitro Antiproliferative Activity of Extracts of Carlina acaulis subsp. caulescens and Carlina acanthifolia subsp. utzka. PMC5469354.
• Wnorowski A. et al. (2020). Toxicity of Carlina Oxide — A Natural Polyacetylene from the Carlina acaulis Roots — In Vitro and In Vivo Study. Toxins (Basel). PMC7232248.
• Herrmann F. et al. (2011). Carlina oxide — a natural polyacetylene from Carlina acaulis (Asteraceae) with potent antitrypanosomal and antimicrobial properties. Planta Medica. PubMed PMID 21678234.
• Rosato A. et al. (2021). Comprehensive Evaluation of the Antibacterial and Antifungal Activities of Carlina acaulis L. Essential Oil and Its Nanoemulsion. Antibiotics (Basel). PMC8698297.
• Strzemski M. et al. (2017). Carlina vulgaris L. as a Source of Phytochemicals with Antioxidant Activity. Oxidative Medicine and Cellular Longevity. Hindawi.
• Đorđević S. et al. Bioactivity Assays on Carlina acaulis and C. acanthifolia Root and Herb Extracts. Digest Journal of Nanomaterials and Biostructures.
• Strzemski M. et al. (2020). Morphological, Anatomical, and Phytochemical Studies of Carlina acaulis L. Cypsela. PMC7730301.
• Benelli G. et al. (2021). Encapsulation of Carlina acaulis essential oil and carlina oxide to develop long-lasting mosquito larvicides. Journal of Pest Science. Springer.
• Benelli G. et al. (2020). Outstanding insecticidal activity and sublethal effects of Carlina acaulis root essential oil on the housefly, Musca domestica, with insights on its toxicity on human cells. Food and Chemical Toxicology. ScienceDirect.
• Frontiers in Pharmacology (2018). Botanical Provenance of Traditional Medicines From Carpathian Mountains at the Ukrainian-Polish Border.
• Synthesis of Carlina Oxide Analogues and Evaluation of Their Insecticidal Efficacy and Cytotoxicity. Journal of Natural Products. ACS Publications.