The aim of this study was to evaluate the phytotoxic, genotoxic, cytotoxic and antimicrobial effects of the Mentha arvensis L. essential oil (EO). The biological activity of M. arvensis EO depended on the analyzed variable and the tested oil concentration. Higher concentrations of EO (20 and 30 µg mL-1) showed a moderate inhibitory effect on the germination and growth of seedlings of tested weed species (Bellis perennis, Cyanus segetum, Daucus carota, Leucanthemum vulgare, Matricaria chamomilla, Nepeta cataria, Taraxacum officinale, Trifolium repens and Verbena × hybrida). The results obtained also indicate that the EO of M. arvensis has some genotoxic, cytotoxic and proliferative potential in both plant and human in vitro systems. Similar results were obtained for antimicrobial activity against eight bacteria, including multidrug-resistant (MDR) strains [Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Escherichia coli, extended-spectrum beta-lactamase-producing (ESBL) E. coli, Pseudomonas aeruginosa and Salmonella enterica subsp. enterica serovar Enteritidis], with the effect on multidrug-resistant bacterial strains. Research indicates that the EO of M. arvensis shows phytotoxic, genotoxic, cytotoxic and antimicrobial effects, as well as its potential application as a herbicide and against various human diseases.

Origanum vulgare L. has been proven to be the strongest herbal antiseptic in the world, native to the Mediterranean region, but is widely naturalized elsewhere in the temperate Northern Hemisphere. This study aimed to estimate the phytotoxic effect of three different concentrations of oregano essential oil (O. vulgare) on three selected plant species namely, wheat, tomato and mint using biotest germination and effects on seedling growth, as well as its toxicological properties using Allium test. Our results revealed that oregano essential oil exhibits allelopathic effect on selected species. All three tested concentrations of oregano essential oil caused a significant inhibition of Allium cepa L. root growth, as well as a reduction in the mitotic index values in A. cepa meristem cells. O. vulgare essential oil demonstrated phytotoxic and antiproliferative effects. Further research is needed to confirm our results.

Cadmium (Cd) is considered one of the most toxic heavy metals to living organisms, being very persistent in soil and non-biodegradable, thus posing a long-term hazard to plants and humans. In recent years, the application of different molecules at the seed level, known as chemical seed priming, has been studied as a method to improve stress tolerance in plants. In the present study, we tested the effect of hydro-priming and proline priming of lettuce (Lactuca sativa L.) seeds on germination, photosynthetic pigments, and metal metabolism under cadmium stress. Plants primed with proline showed better germination under cadmium stress (100% versus 84% for non-primed and hydro-primed seeds). Priming with 20 mM of proline increased the chlorophyll a and total chlorophyll contents by 40.8% and 18.6%, respectively, while these parameters decreased in other seedlings under Cd stress. Similarly, 20 mM of proline improved the uptake of Zn and Fe in roots under Cd stress. This indicates that 20 mM of proline treatments may be beneficial for maintaining a normal photosynthetic capacity and mineral uptake under Cd stress, but further metabolomics and transcriptomic data should reveal the exact mechanisms of action.

To improve our understanding of the molecular mechanisms underlaying seed priming, RNA transcriptome analysis was performed using primed and non-primed seeds of Silene sendtneri. Seed priming was performed by submergence in 1% silicic acid for 24h at 4°C, followed by rinsing with sterilised water and desiccation to original moisture content. Silene sendtneri is a species with no sequenced genome and annotation of de novo assembly of transcriptome was done against several species. Gene ontology (GO) analysis indicated that genes related to heavy metal transporters and heat shock proteins are differentially expressed after priming with silicic acid. Within these gene categories, genes such as heavy metal-associated isoprenylated plant protein 26-like (log2fold -8.79) were downregulated, while others such as heavy metal ATPase 5 (log2fold 6.46), heat shock factor protein HSF30-like isoform X1 (log2fold 5.98) were upregulated.

Genus Silene (Caryophyllaceae) is very rich in secondary metabolites and has an antiviral, antimalarial, antitumor, antibacterial and antioxidant properties, but Balkan endemic Silene sendtneri (Sendtner's campion) is not analyzed from the aspect of phenolic composition and their biological activities. Evaluation of total phenolic contents (TPC) and total flavonoid contents (TFC), and antioxidant and antimicrobial activities of hydromethanolic extracts from inflorescences, stem, rhizome, and seeds of S. sendtneri, was done in this study for the first time. The TPC, TFC, and antioxidant activity (DPPH; 2,2-diphenyl-1-picrylhydrazyl) were determined by UV/VIS spectrophotometry. Antimicrobial activity was estimated against selected test microorganisms (Staphylococcus epidermididis, Staphylococcus aureus subsp. aureus, Salmonella abony, Escherichia coli, and Candida albicans) using a disc diffusion assay. The inflorescences had the highest (11.587 mg GAEg-1 DW) and rhizome the lowest TPC (2.017 mg GAEg-1 DW). The inflorescences extract exhibited the highest TFC (69.824 mg CEg-1 DW), while TFC was not detected in the rhizome extract. The stem’s extract had the highest antioxidant activity (IC50; 20.51%), while the rhizome had the lowest (61.89%). All extracts showed moderate antibacterial activity against Staphylococcus epidermididis and low activity against the three remaining tested organisms. Antifungal activity of inflorescence and rhizome extracts was moderate. Obtained results provide a basis for further investigations of various S. sendtneri extracts, which can be a potential natural antioxidant and antimicrobial agents

UDK: 582.661.51:631.53.027]:547.913 In order to investigate the effects of seed priming with silver fir and oregano essential oils on certain important seedling characteristic and seed vigour of interesting endemic and horticultural species Silene sendtneri, an experiment was conducted based on randomized completely design with three replications. Traits such as germination rate, water content, dry weight, vigour index and photosynthetic pigments were analysed. Results revealed that the seedlings obtained with priming seeds showed increased growth, water content, vigour and photosynthetic pigment contents but decreased germination rate and dry weight compared with that obtained with non-primed seeds. Analysis of seed priming effects had demonstrated even germination rate is smaller the seedling vigour is slightly higher especially with all oregano oil treatments. We suggest that oregano oil has a potential as a priming agent for improvement of seedling synchrony, although at lower rate of germination.

Gentiana lutea L. is a medicinal plant the roots of which are primarily used in treatments of various human digestive disorders, but also the production of alcoholic liquors. The roots (radix) of G. lutea are described in the European Pharmacopeia, but knowledge about the chemical composition and biological activities of its aerial parts is still limited. Thus, until today aerial parts of this species have not been used in medical treatments or consumed. Therefore, flowers, leaves, and stems extracts of G. lutea obtained by using four different extraction solvents (petrol ether, chloroform, ethanol, and water) were examined for their chemical composition and biological activities. High concentrations of salicylic acid, apigenin, and naringenin were recorded for ethanol stem extracts, while significant amounts of kaempferol were detected in leaves and flowers in chloroform and water extracts, respectively. The highest antioxidant potential was recorded for flower and stem petrol ether extracts with the lowest IC50 values, ranging from 94.46 ± 9.45 to 105.38 ± 10.54 μg/mL. Ethanol extracts of flowers and stems showed moderate antioxidant activity (IC50 143.15 ± 14.32 and 146.90 ± 14.69 μg/mL) as well as strong antimicrobial activity against Candida albicans (21.00 ± 1.00 and 27.50 ± 1.78 mm inhibition zones, respectively). In addition, ethanol extracts had higher antimycotic activity compared to naturally occurring phenolic compounds that are used as positive controls. Moreover, statistical analysis of the activities of plant extracts and single compounds showed that levels of chlorogenic and caffeic acids strongly correlate with the biological activities of the extracts, i.e., they are the main carriers of these biological activities. The presented results indicate the possible use of aerial parts of G. lutea as a natural preservative, as well as a antimicrobial agent, which significantly amplifies the benefits of this medicinal crop and greatly affects the sustainability of cultivated Gentiana plantation.

The phenolic composition, as well as the antioxidant and antimicrobial activities of two poorly investigated Achillea species, Achillea lingulata Waldst. and the endemic Achillea abrotanoides Vis., were studied. To obtain a more detailed phytochemical profile, four solvents with different polarities were used for the preparation of the plant extracts whose phenolic composition was analyzed using UHPLC-MS/MS (ultra-high performance liquid chromatography-tandem mass spectrometry). The results indicate that both of the investigated Achillea species are very rich in both phenolic acids and flavonoids, but that their profiles differ significantly. Chloroform extracts from both species had the highest yields and were the most chemically versatile. The majority of the examined extracts showed antimicrobial activity, while ethanolic extracts from both species were potent against all tested microorganisms. Furthermore, the antioxidant activity of the extracts was evaluated. It was found that the ethanolic extracts possessed the strongest antioxidant activities, although these extracts did not contain the highest amounts of detected phenolic compounds. In addition, several representatives of phenolic compounds were also assayed for these biological activities. Results suggest that ethanol is a sufficient solvent for the isolation of biologically active compounds from both Achillea species. Moreover, it was shown that the flavonoids naringenin and morin are mainly responsible for these antimicrobial activities, while caffeic, salicylic, chlorogenic, p-coumaric, p-hydroxybenzoic, and rosmarinic acid are responsible for the antioxidant activities of the Achillea extracts.