In the present study, the antimicrobial and antiradical activities of 15 essential oils were investigated. The antimicrobial activities were determined by using agar disc diffusion and broth microdilution methods against Clostridium genus and antioxidant properties of essential oils by testing their scavenging effect on DPPH radicals activities. We determined the antibacterial activity of Clostridium butyricum, Clostridium hystoliticum, Clostridium intestinale, Clostridium perfringens and Clostridium ramosum. We obtained the original commercial essential oils samples of Lavandula angustifolia, Carum carvi, Pinus montana, Mentha piperita, Foeniculum vulgare Mill., Pinus sylvestris, Satureia montana, Origanum vulgare L. (2 samples), Pimpinella anisum, Rosmarinus officinalis L., Salvia officinalis L., Abies alba Mill., Chamomilla recutita L. Rausch and Thymus vulgaris L. produced in Slovakia (Calendula a.s., Nova Lubovna, Slovakia). The results of the disk diffusion method showed very high essential oils activity against all tested strains of microorganisms. The best antimicrobial activity against C. butyricum was found at Pimpinella anisum, against C. hystoliticum was found at Pinus sylvestris, against C. intestinale was found at Satureia hortensis L., against C. perfringens was found at Origanum vulgare L. and against C. ramosum was found at Pinus sylvestris. The results of broth microdilution assay showed that none of the essential oils was active against C. hystoliticum. The best antimicrobial activity against C. butyricum was found at Abies alba Mill., against C. intestinale was found at Abies alba Mill., against C. perfringens was found at Satureia montana and against C. ramosum was found at Abius alba and Carum carvi. Antioxidant DPPH radical scavenging activity was determined at several solutions of oil samples (50 μL.mL⁻¹–0.39 μL.mL⁻¹) and the best scavenging effect for the highest concentration (50 μL.mL⁻¹) was observed. The antioxidant properties were different in particular plant species. The highest% of inhibition after 30 min. of reaction was observed at Origanum vulgare (93%), Satureia montana (90.66%) and Lavandula augustifolia (90.22%).

Thyme belongs to a genus encompassing over 215 species of hardy perennial herbaceous plants and sub-shrubs, which are native to Europe, particularly around the Mediterranean. Thymus vulgaris L., or garden thyme, with narrow small leaves and clusters of tubular mauve flowers, is used mainly in cookery. Dried herb yields 1% and more essential oil, which is a pale yellowish-red liquid with a sweet, very aromatic odour. Thyme is widely used in the pharmaceutical industry and is a source of substances of antimicrobial effect upon antibiotic-resistant strains of microorganisms. The purpose of our work was to identify the biochemical and antimicrobial peculiarities of Th. vulgaris essential oil against clinical isolates of opportunistic microorganisms. The analysis of thyme essential oil was carried out using GC/MS analysis. The clinical isolates were isolated with the use of differentially diagnostic nutrient media. The antibiotic susceptibility was identified with the help of the disc-diffusion test. The sensitivity of microorganisms to plant extracts was determined by the agar diffusion test. The antibiofilm activity of the extracts was tested in standard 96-well microtitration plates. The GC/MS results confirm the earlier reports that the major volatile constituents obtained from the aerial parts of thyme species were thymol, γ-terpinene, p-cymene, 3-carene and carvacrol. After subjecting the selected essential oil to effective steam distillation, substantial contents of phenolic monoterpenoids were obtained – thymol (67.7%) and γ-terpinene (8.2%). The European Pharmacopoeia set quality standards for thyme essential oil, which dealt mainly with the % content (w/w) of the volatile phenols (expressed as thymol: 36.0–55.0%). Garden thyme essential oil has been found to show a high antimicrobial activity against antibiotic-resistant microorganism strains. The obtained results proved the wide spectrum of antibiotic activity of thyme essential oil. The highest antimicrobial activity was registered against the typical and clinic strains of S. aureus and microscopic Candida genus fungi. Garden thyme essential oil was ascertained to show high antibiofilm-forming activity against S. aureus. The antimicrobial and antibiofilm-forming activities of thyme essential oil against both bacterial pathogens of opportunistic infections and microscopic fungi have proven the good prospects for development of a broad-spectrum agent against opportunistic microbial associations based on this oil.

Juniperus excelsa M. Bieb and J. sabina L. contain essential oil (EO), while J. sabina also contains podophyllotoxin, which is used as a precursor for anti-cancer drugs. Two studies were conducted. The first assessed the variability in the EO profile and podophyllotoxin concentration of the two junipers, depending on the location and tree gender. The main EO constituents of J. excelsa were α-cedrol, α-limonene and α-pinene, while the constituents in J. sabina were sabinene, terpinen-4-ol, myrtenyl acetate and α-cadinol. The podophyllotoxin yield of 18 J. sabina accessions was 0.07–0.32% (w/w), but this was not found in any of the J. excelsa accessions. The second study assessed the effect of hydrodistillation (Clevenger apparatus) and steam distillation (in a semi-commercial apparatus) on the EO profile and bioactivity. The extraction type did not significantly alter the EO composition. The EO profiles of the two junipers and their accessions were different and may be of interest to the industry utilizing juniper leaf EO. Breeding and selection programs could be developed with the two junipers (protected species) in order to identify chemotypes with (1) a high EO content and desirable composition, and (2) a high concentration of podophyllotoxin in J. sabina. Such chemotypes could be established as agricultural crops for the commercial production of podophyllotoxin and EO.

Natural phytonutrients in foods, including anthocyanins, can play an important role in human health. Anthocyanins have been reported to cause many various useful effects, such as reducing cancer cell proliferation, regulating blood pressure, preventing tumor formation, and preventing diabetes. In this study, we aimed to reveal the qualitative anthocyanin content, antiproliferative and antimicrobial effects of different extracts derived from Vaccinium myrtillus, Vaccinium corymbosum, Sambucus nigra and Aronia melanocarpa. The anthocyanin content of the plants mentioned in the study was characterized after the freeze-drying process. MTT assay was chosen to determine the antiproliferative effect of extracts on colorectal cancer cells. Antimicrobial effects of extracts were studied on typical and clinical strains of five different bacteria. As a result, it was determined that the anthocyanin content in the extracts obtained by the freeze-drying method was acceptable, and some extracts were found to have a strong antiproliferative effect on colorectal cancer cells and have an antibacterial effect on typical and clinical strains. Conclusionally, it has been shown that anthocyanins, which are reported to have many beneficial effects, are very promising when prepared with a relatively new method, and this study is a pioneer study for possible future pharmacological and in vivo studies.

Selections of chamomile, Chamomilla recutita (L.) Rauschert, have resulted in the development of types with higher oil concentrations and considerable differences in essential oil constituents. Tests on mechanical chamomile harvesters indicated a vacuum system worked best for transport of flower heads preventing damage to the tissue.