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

Fractionation of Carlina acaulis L. Root Methanolic Extract as a Promising Path towards New Formulations against Bacillus cereus and Methicillin-Resistant Staphylococcus aureus

The root of Carlina acaulis L. has been widely used in traditional medicine for its antimicrobial properties. In this study, the fractionation of methanol extract from the root was conducted. Four fractions (A, B, C, and D) were obtained and tested against a range of bacteria and fungi. The results showed promising antibacterial activity, especially against Bacillus cereus, where the minimal inhibitory concentration (MIC) was determined to be equal to 0.08 mg/mL and 0.16 mg/mL for heptane (fraction B) and ethyl acetate (fraction C), respectively. In the case of the methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300 strain, the same fractions yielded higher MIC values (2.5 and 5.0 mg/mL, respectively). This was accompanied by a lack of apparent cytotoxicity to normal human BJ foreskin fibroblasts, enterocytes derived from CaCo2 cells, and zebrafish embryos. Further analyses revealed the presence of bioactive chlorogenic acids in the fractionated extract, especially in the ethyl acetate fraction (C). These findings support the traditional use of the root from C. acaulis and pave the way for the development of new formulations for treating bacterial infections. This was further evaluated in a proof-of-concept experiment where fraction C was used in the ointment formulation, which maintained high antimicrobial activity against MRSA and displayed low toxicity towards cultured fibroblasts.

A Chemometry of Aldrovanda vesiculosa L. (Waterwheel, Droseraceae) Populations

The genus Aldrovanda is a Palaeogene element containing a single extant species, Aldrovanda vesiculosa L. This aquatic carnivorous herb has a very wide range of distribution, natively covering four continents; however, it is a critically endangered aquatic plant species worldwide. Previous studies revealed that A. vesiculosa had an extremely low genetic variation. The main aim of the present paper is to explore, using chemometric tools, the diversity of 16 A. vesiculosa populations from various sites from four continents (Eurasia, Africa, Australia). Using chemometric data as markers for genetic diversity, we show the relationships of 16 A. vesiculosa populations from various sites, including four continents. Phytochemical markers allowed the identification of five well-supported (bootstrap > 90%) groups among the 16 populations sampled. The principal component analysis data support the idea that the strongly related African (Botswana) and Australian (Kimberley, NT, NW Australia) populations are the most distant ones, separated from the European and Asian ones. However, considering the five Australian populations sampled, three are nested within the Eurasian group. The chemometric data are correlated positively with the geographical distances between the samples, which suggests a tendency toward isolation for the most distant populations.

Morphological, Anatomical, and Phytochemical Studies of Carlina acaulis L. Cypsela

Carlina acaulis L. has a long tradition of use in folk medicine. The chemical composition of the roots and green parts of the plant is quite well known. There is the lowest amount of data on the cypsela (fruit) of this plant. In this study, the microscopic structures and the chemical composition of the cypsela were investigated. Preliminary cytochemical studies of the structure of the Carlina acaulis L. cypsela showed the presence of substantial amounts of protein and lipophilic substances. The chemical composition of the cypsela was investigated using spectrophotometry, gas chromatography with mass spectrometry, and high-performance liquid chromatography with spectrophotometric and fluorescence detection. The cypsela has been shown to be a rich source of macro- and microelements, vegetable oil (25%), α-tocopherol (approx. 2 g/kg of oil), protein (approx. 36% seed weight), and chlorogenic acids (approx. 22 g/kg seed weight). It also contains a complex set of volatile compounds. The C. acaulis cypsela is, therefore, a valuable source of nutrients and bioactive substances.

Toxicity of Carlina Oxide-A Natural Polyacetylene from the Carlina acaulis Roots-In Vitro and In Vivo Study

There are several reports indicating that the roots of the 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 importance. 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. Here, we aimed to determine the toxicity profile of carlina oxide, one of the most abundant components of the C. acaulis root extract. We obtained the carlina oxide by distillation of C. acaulis roots in the Deryng apparatus. The purity of the standard was evaluated using GC-MS, and the identity was confirmed by IR, Raman, and NMR spectroscopy. In vitro cytotoxicity was assessed using a panel of human cell lines of skin origin, including BJ normal fibroblasts and UACC-903, UACC-647, and C32 melanoma cells. This was accompanied by an in vivo zebrafish acute toxicity test (ZFET). 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 extracellular signal-regulated kinase 1/2 (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. Carlina oxide exhibited high in vivo toxicity, with LC₅₀ = 10.13 µg/mL upon the 96 h of exposure in the ZFET test. Here, we demonstrate that carlina oxide displays toxic effects to cells in culture and to living organisms. The data indicate that C. acaulis-based extracts considered for therapeutic use should be completely deprived of carlina oxide.

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.

Metabolic Changes Induced by Silver Ions in Carlina acaulis

Silver is one of the most toxic heavy metals for plants, inducing various toxic symptoms and metabolic changes. Here, the impact of Ag(I) on Carlina acaulis physiology and selected metabolites was studied using two Ag concentrations (1 or 10 µM) after 14 days of exposure. The higher concentration of Ag(I) evoked reduction of growth, while 1 µM Ag had a growth-promoting effect on root biomass. The translocation factor (<0.04) showed that Ag was mainly retained in the roots. The 1 µM Ag concentration increased the level of low-molecular-weight organic acids (LMWOAs), while 10 µM Ag depleted these compounds in the roots. The increased concentration of Ag(I) elevated the accumulation of phytochelatins (PCs) in the roots and reduced glutathione (GSH) in the shoots (but not in the roots). At 1 µM, Ag(I) elevated the level of phenolic and triterpene acids, while the 10 µM Ag treatment increased the carlina oxide content in the roots. The obtained results indicate an alteration of metabolic pathways of C. acaulis to cope with different levels of Ag(I) stress. Our data imply that the intracellular binding of Ag(I) and nonenzymatic antioxidants contribute to the protection against low concentrations of Ag ions.