Composition of the Essential Oil from the Root ofCarlina acaulisL. Asteraceae

Lethal and sublethal effects of carlina oxide on Tetranychus urticae (Acari: Tetranychidae) and Neoseiulus californicus (Acari: Phytoseiidae)

BACKGROUND

Tetranychus urticae Koch, is a polyphagous and damaging pest, presenting several resistant populations worldwide. Among new and more environmentally friendly control tools, botanical pesticides represent a valuable alternative to synthetic ones within integrated pest management strategies. Accordingly, we investigated the lethal and sublethal effects of carlina oxide isolated from Carlina acaulis (Asteraceae) roots on T. urticae and its natural enemy, the predatory mite, Neoseiulus californicus (McGregor).

RESULTS

Carlina oxide (98.7% pure compound) was used for acaricidal tests on eggs, nymphs, and adult females of T. urticae (concentrations of 312.5, 625, 1250, 2500 and 5000 μL L-1 ), and eggs and females of N. californicus (1250 and 5000 μL L-1 on eggs and females, respectively). Behavioral two-choice tests were also conducted on phytoseiid females. Carlina oxide toxicity was higher on T. urticae females than nymphs (median lethal dose 1145 and 1825 μL L-1 , respectively), whereas egg mortality and mean hatching time were significantly affected by all tested concentrations. A decreasing daily oviposition rate for T. urticae was recorded with concentrations ranging from 625 to 5000 μL L-1 , whereas negative effects on the population growth rate were recorded only with the three higher concentrations (1250, 2500 and 5000 μL L-1 ). No toxic effect on N. californicus females was found, but a strong repellent activity lasting for 48 h from application was recorded.

CONCLUSION

Carlina oxide reduced longevity and fecundity of T. urticae adults, but not of N. californicus. This selective property allows us to propose it as a novel active ingredient of ecofriendly acaricides for T. urticae management. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Carlina oxide inhibits the interaction of SARS-CoV-2 S glycoprotein with angiotensin-converting enzyme 2

Carlina acaulis plant is a potential target for the industrial production of phytochemicals that display applicability in pharmacy and medicine. The dry roots of C. acaulis contain up to 2 % of essential oil, the main component (up to 99 %) of which is carlina oxide [2-(3-phenylprop-1-ynyl)furan]. This compound shows multidirectional biological activity, including antibacterial and antifungal properties. Here, we evaluated the capacity of carlina oxide to inhibit the interaction between SARS-CoV-2 and its human receptor in vitro and in silico. A bioluminescent immunoassay was used to study the interaction between the receptor binding domain (RBD) of viral spike protein and the human angiotensin-converting enzyme 2 (ACE2), which serves as a receptor for viral entry. A dose-effect relationship was demonstrated, and a concentration of carlina oxide causing half-maximal inhibition (IC₅₀) of the RBD:ACE2 interaction was determined to be equal to 234.2 µg/mL. Molecular docking suggested the presence of carlina oxide binding sites within the RBD and at the interface between RBD and ACE2. Finally, this study expands the list of potential applications of C. acaulis as a crop species.

Back to the Roots-An Overview of the Chemical Composition and Bioactivity of Selected Root-Essential Oils

Since ancient times, plant roots have been widely used in traditional medicine for treating various ailments and diseases due to their beneficial effects. A large number of studies have demonstrated that-besides their aromatic properties-their biological activity can often be attributed to volatile constituents. This review provides a comprehensive overview of investigations into the chemical composition of essential oils and volatile components obtained from selected aromatic roots, including Angelica archangelica, Armoracia rusticana, Carlina sp., Chrysopogon zizanioides, Coleus forskohlii, Inula helenium, Sassafras albidum, Saussurea costus, and Valeriana officinalis. Additionally, their most important associated biological impacts are reported, such as anticarcinogenic, antimicrobial, antioxidant, pesticidal, and other miscellaneous properties. Various literature and electronic databases-including PubMed, ScienceDirect, Springer, Scopus, Google Scholar, and Wiley-were screened and data was obtained accordingly. The results indicate the promising properties of root-essential oils and their potential as a source for natural biologically active products for flavor, pharmaceutical, agricultural, and fragrance industries. However, more research is required to further establish the mechanism of action mediating these bioactivities as well as essential oil standardization because the chemical composition often strongly varies depending on external factors.

Chemical Composition and Biological Activities of Essential Oils of Echinops spinosus and Carlina vulgaris Rich in Polyacetylene Compounds

Background:

The essential oils of aromatic plants are increasingly used as new biocontrol alternative agents against microbial strains and insect pests of fruits and vegetables, because of their specificity of biodegradable nature.

Objective:

This work, treats for the first time the chemical composition, antioxidant, antifungal and insecticidal activities of the essential oils obtained from Echinops spinosus and Carlina vulgaris from Algeria.

Methods:

The chemical compositions of oils were investigated using GC-FID and GC/MS. Antioxidant activity was assessed using three methods (2,2-diphenyl-1-picrylhydrazyl, Ferric-Reducing Antioxidant Power (FRAP) and β-carotene assay). Fumigation toxicity of E. spinosus and C. vulgaris essential oils was tested against Bactrocera oleae pests of olives.

Results:

Eighteen and thirteen components representing 95.4 and 97.9% were identified in root essential oils from Echinops spinosus and Carlina vulgaris, respectively. Polyacetylenes were the majority compounds of essential oils. 5 (But-1-yn-3-enyl).2,2'bithiophene and α-terthienyle were highly dominants in the E. spinosus essential oil from the roots (54.4 and 26.3%, respectively). Roots of C. vulgaris produce an essential oil dominated by carlina oxide (33.7%) and 13-methoxy carlina oxide (11.5%). Comparison of the antioxidant activity of E. spinosus essential oil showed more important antioxidant effect than C. vulgaris essential oil and the synthetic antioxidant (BHT). Evaluation of the antifungal activity showed an interesting efficiency of both essential oils against P. expansum and A. niger with EC50s varied from 5 to 14.5 mg/L. C. arvensis essential oil exhibited good larvicidal properties. At the concentration of 325 μL/L air, the oil caused mortality of 100% for Bactrocera Oleae adults after 24 h of exposure.

Conclusion:

Both essential oils rich to polyacetylenes and polythiophenes.components have shown interesting biological activities, which suggests that plants have the potential to be used as biopesticides and provide an alternative to chemical pesticides.

The Impact of Different Cultivation Systems on the Content of Selected Secondary Metabolites and Antioxidant Activity of Carlina acaulis Plant Material

Roots and leaves of Carlina acaulis L. are still used in ethnomedicine in many European countries; however, the limited occurrence of the plants and protection of this species necessitate a search for alternative ways for obtaining this plant material. In this study, in vitro cultures, hydroponic cultures, and field cultivation were applied to obtain the C. acaulis plant material. Its quality was evaluated using antioxidant activity tests and high performance liquid chromatography analysis. Our study showed that the antioxidant activity and the content of chlorogenic and 3,5-di-caffeoylquinic acid in roots of plants cultivated in hydroponics and field conditions were comparable. However, the amount of carlina oxide was significantly higher in plants from the field. The flavonoid content in leaves obtained from both cultivation systems was at the same level; however, the antioxidant activity and the content of the investigated metabolites were higher in the soil cultivation system. The callus line exhibited high differentiation in phytochemical compositions depending on the treatments and medium compositions.

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

Carlina acaulis (Compositae) is traditionally used for food and medicinal purposes in central and southern Europe. Its root essential oil (EO), mainly composed by carlina oxide, is included in the BELFRIT botanical list of food supplements. It is also recognized as a potent mosquito larvicide. It is matter of concern whether this EO could be endowed with intrinsic toxicity to limit its use on a food level. Focusing on the insecticidal activity of this EO, we investigated the acute toxicity and sublethal effects on Musca domestica. In topical assays, the EO was extremely effective (LD₅₀ = 2.74 and 5.96 μg fly^-1, on males and females, respectively). The exposure to a sublethal dose (LD₃₀) led to significant reductions of female longevity (LT₅₀ = 6.7-9.0 days vs. control LT₅₀ = 12.9-13.7 days). Treated females laid 2.5 times fewer eggs over control ones. F₁ vitality decreased: F₁ larvae and pupae showed high mortality, 2-4-fold higher over the control. The EO also showed high cytotoxicity on normal human fibroblasts (NHF-A12, IC₅₀ = 9.4-14.2 μg mL^-1 after 6-48 h). Overall, our findings support the employ of this EO for developing botanical insecticides. At the same time, they encourage food safety authorities to perform a full toxicological assessment for possible restrictions at food level.

Historical and traditional medical applications of Carlina acaulis L. - A critical ethnopharmacological review

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Carlina (Asteraceae) comprises approx. 30 plant species growing in Europe and Asia. Carlina acaulis L. was widely used as medicine, especially in Germany and Poland. The plant root was applied e.g. 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.

AIM OF THE REVIEW

The aim of this review is to compile historical and current ethnomedical uses of C. acaulis and compare these applications with the results of modern chemical and pharmacological research of this plant. This analysis may give a lead for further research on this old, almost forgotten medicinal plant.

METHODOLOGY

Historical data on the medicinal application of C. acaulis over many centuries were collected. The historical uses were compared with the contemporary indications. The present day knowledge on the chemistry and biological activity of C. acaulis is also reviewed. This information is compared with the ethnopharmacological information.

RESULTS

Plants from the genus Carlina were already described by Theophrastus of Eresus, Dioscorides, Pliny the Elder, and Galen of Pergamum. Carlinae radix was still featured in Renaissance botanical books and in official pharmacopoeias, but disappeared from the scene in the 19th century. 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. However, most concern the green parts of the plant. Its medicinal use remains poorly understood, as there are only very limited results of in-vitro studies on the roots.

CONCLUSIONS

The historical uses of the plant can still be found in rural areas. Yet, detailed phytochemical and pharmacological research is needed to evaluate the effectiveness and safety of the medical use of Carlina acaulis.

Methodological approach to determine carlina oxide - a main volatile constituent of Carlina acaulis L. essential oil

In this work, a fast and low-cost voltammetric methodology for determination of carlina oxide in plant extracts was developed. The best results were obtained using a boron-doped diamond electrode (BDDE). The voltammetric measurements of carlina oxide were performed in a 0.1 mol/L solution of sulphuric acid. After 30 s of stirring the solution, differential pulse voltammograms (DPVs) were recorded from 0.5 to 1.8 V. The amplitude was 75 mV and the scan rate was 175 mV/s. Measurements were recorded in non-deaerated solutions. The background current was subtracted from each registered voltammogram; then they were cut from 0.5 to 1.5 V. The detection and quantification limits were 0.28 and 0.93 μg/L, respectively, and repeatability expressed as the relative standard deviation of 0.1 mg/L of carlina oxide was 1.9% (n = 5). The results were compared with those obtained using gas chromatography with a flame ionization detector and high performance liquid chromatography with a photodiode array detector.

Application of Raman spectroscopy for direct analysis of Carlina acanthifolia subsp. utzka root essential oil

Carlina genus plants e.g. Carlina acanthifolia subsp. utzka have been still used in folk medicine of many European countries and its biological activity is mostly associated with root essential oils. In the present paper, Raman spectroscopy (RS) was applied for the first time for evaluation of essential oil distribution in root of C. acnthifolia subsp. utzka and identification of root structures containing the essential oil. Furthermore, RS technique was applied to assess chemical stability of oil during drying of plant material or distillation process. Gas chromatography-mass spectrometry was used for qualitative and quantitative analysis of the essential oil. The identity of compounds was confirmed using Raman, ATR-IR and NMR spectroscopy. Carlina oxide was found to be the main component of the oil (98.96% ± 0.15). The spectroscopic study showed the high stability of essential oil and Raman distribution analysis indicated that the oil reservoirs were localized mostly in the structures of outer layer of the root while the inner part showed nearly no signal assigned to the oil. Raman spectroscopy technique enabled rapid, non-destructive direct analysis of plant material with minimal sample preparation and allowed straightforward, unambiguous identification of the essential oil in the sample.

Carlina acaulis Exhibits Antioxidant Activity and Counteracts Aβ Toxicity in Caenorhabditis elegans

Carlina acaulis is a medicinal plant that has shown antioxidant activity in in vitro studies, but to date no corresponding in vivo data is available. Therefore, in the present study the antioxidant activity and its impact in counteracting Aβ toxicity were studied in the Caenorhabditis elegans model. A dichloromethane extract of the roots of C. acaulis was prepared and characterised via gas-liquid-chromatography/mass-spectrometry (GLC-MS). The in vitro antioxidant activity was confirmed via 2,2-diphenyl-1-picrylhydracyl assay. The extract was further separated by thin layer chromatography into two fractions, one of which was a fraction of the dichloromethane extract of C. acaulis containing mostly Carlina oxide (CarOx). Different strains of C. elegans were employed to study the expression of hsp-16.2p::GFP as a marker for oxidative stress, delocalisation of the transcription factor DAF-16 as a possible mechanism of antioxidant activity, the effect of the drug under lethal oxidative stress, and the effect against beta-amyloid (Aβ) toxicity in a paralysis assay. The C. acaulis extract and CarOx showed high antioxidant activity (stress reduction by 47% and 64%, respectively) in C. elegans and could activate the transcription factor DAF-16 which directs the expression of anti-stress genes. In paralysis assay, only the total extract was significantly active, delaying paralysis by 1.6 h. In conclusion, in vivo antioxidant activity was shown for C. acaulis for the first time in the C. elegans model. The active antioxidant compound is Carlina oxide. This activity, however, is not sufficient to counteract Aβ toxicity. Other mechanisms and possibly other active compounds are involved in this effect.

Commercial Carlinae radix herbal drug: botanical identity, chemical composition and antimicrobial properties

CONTEXT

Carlinae radix is an herbal drug, commonly used by the locals in southeastern Serbia for the treatment of respiratory and urogenital diseases and, externally, for various skin conditions. There still seems to be no detailed studies correlating the chemical composition of this drug and its ethnopharmacological uses.

OBJECTIVE

Chemical composition, antimicrobial activity and mode of action of C. radix essential oil, isolated from commercial samples (confirmation of whose true biological identity was also the aim of this work) were analyzed. Antimicrobial potential of decoctions (extracts prepared by boiling plant material in a given solvent), used in ethnomedicine preferentially to the pure essential oil, was also investigated.

MATERIALS AND METHODS

The essential oil obtained by hydrodistillation was screened for antimicrobial activity by disc diffusion and broth microdilution methods. Effects of the oil on the growth of Staphylococcus aureus cells were investigated using turbidimetric measurements and visualized using scanning electron microscopy. Analyses of the chemical composition of the oils were done using gas chromatography and gas chromatography/mass spectrometry.

RESULTS AND DISCUSSION

Both the essential oil and the decocts exhibited a very high antimicrobial activity against all tested strains, with S. aureus as the most sensitive one [e.g., for the oil sample the values for minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were 0.02, 0.04 µL/mL, respectively]. Growth curves of S. aureus demonstrated a significant decrease in turbidity (for the MIC concentration this amounted to ca. 70%) showing a concentration-dependent lysis of the cells, confirmed by scanning electron microscopy. Chemical composition, anatomical and morphological features of the sample pointed to Carlina acanthifolia L. (Asteraceae) instead of Carlina acaulis L. (Asteraceae).

CONCLUSION

The results showed significant antimicrobial effect of the essential oil and the decoctions and support the use of this plant in ethnomedicine for the treatment of various human infections, especially those caused by S. aureus. Adulteration of the drug would not cause significant differences in its biological activity, since chemical composition of the sample showed high similarity with those containing C. acaulis roots.

Antimicrobial, anti-inflammatory, anti-ulcer and antioxidant activities of Carlina acanthifolia root essential oil

The root of Carlina acanthifolia All. (Asteraceae) has been traditionally used in the treatment of various disorders including stomach and skin diseases. We studied antimicrobial, anti-inflammatory, anti-ulcer and antioxidant activities of Carlina acanthifolia root essential oil, in order to validate some of the ethnopharmacological claims. Antimicrobial activity was tested on 15 bacteria and three strains of fungi using the agar diffusion and broth microdilution methods. In assessing anti-inflammatory activity the carrageenan-induced rat paw oedema test was used, while ethanol-induced stress gastric ulcer test in rats was used in testing anti-ulcer activity. Antioxidant properties were evaluated trough the effect of the essential oil on lipid peroxidation (TBA assay) and its capability of quenching 2,2-diphenyl-1-picrylhydrazyl (DPPH) and OH radicals. The oil expressed significant antimicrobial activity, being the most active against Gram (+) bacteria: Streptococcus pyogenes, Enterococcus faecalis, Bacillus subtilis and against Candida albicans. In all applied concentrations, Carlina acanthifolia root essential oil reduced carrageenan-induced rat paw oedema in dose-dependent manner, achieving high degree of anti-inflammatory activity. The effect was comparable with that of indomethacin used as a reference drug. In the ethanol-induced stress gastric ulcer test in rats, it was shown that the tested essential oil produced significant dose-dependent gastroprotective activity. The results also pointed out substantial and dose-dependent antioxidant activity of the investigated essential oil, with carlina oxide as the main antioxidant component.