H. italicum essential oil (EO) is one of the most popular ingredients utilized by the cosmetic industry, and it is also used as natural antioxidant and as a value-added ingredient in food products. The chemical composition of the EO H. italicum cultivated in Serbia was analyzed by gas chromatography–mass spectrometry. The quantitative structure–retention relationship was used to predict the retention indices of the EO constituents acquired by GC-MS data, applying five molecular descriptors selected by factor analysis and a genetic algorithm. Also, antimicrobial activity, and biological activity by four common antioxidant tests (DPPH and ABTS assays, reducing power, and β-carotene bleaching test), and in vitro antihyperglycemic and anti-inflammatory capacities were evaluated. A total of 70 EO constituents were detected, of which 17 (8.5%) could not be identified. The H. italicum EO in this study belonged to γ-curcumene chemotype. The coefficients of determination reached the value of 0.964, demonstrating that this model could be used for prediction purposes. All applied tests showed that H. italicum EO possesses good biological activity and an interesting chemical composition. Therefore, the EO of H. italicum grown in Serbia has a potential to be used in food, cosmetic, and pharmaceutical products.

This study aimed to investigate the chemical composition of steam distillate essential oil and corresponding hydrolate obtained from S. officinalis grown in Serbia, as well as the influence of weather conditions (temperature and precipitations) on their chemical profiles. Furthermore, their antimicrobial activity was investigated in vitro. The main compounds in essential oil were cis-thujone, followed by camphor, trans-thujone, and 1,8-cineole, while hydrolate was slightly different from the essential oil, with camphor, cis-thujone, and 1,8-cineole as the main compounds. Among the eight respiratory-associated microorganisms, Klebsiella oxytoca was the most sensitive to the tested EOs (minimum inhibitory concentration (MIC)/minimal bactericidal/fungicidal concentration (MBC/MFC) were 14.20 and 28.4 μL mL⁻¹, respectively). MIC and MBC values of other tested bacteria ranged between 28.40 and 227.25 μL mL⁻¹ while for Candida albicans MIC/MFC ranged from 28.40/56.81 to 56.81–113.63 μL mL⁻¹. Antibiotic susceptibility patterns for the analyzed eight respiratory-associated microorganisms showed an intermediate level of resistance to commonly used antibiotics such as ampicillin, levofloxacin, and ciprofloxacin. As a preliminary approach to the antimicrobial profiling of the tested EO, the obtained results revealed that the tested samples possess remarkable antibacterial activities and could be used to develop pharmaceutical formulations as an alternative to conventional antibiotic therapy.

The aim of this study was to test the quality (physicochemical and sensory odor properties) and bioactivity (antimicrobial and antioxidant activities) of the essential oils (EO) obtained from the most frequently cultivated lavender and lavandin varieties in Serbia, whose cultivation areas were previously reserved for warmer climates, outside the agroecological region of Serbia. Seven EO from true lavenders (L. angustifolia Mill. and cultivars: ‘Hidcote blue’, ‘Munstead’, ‘Primorska’), Croatian indigenous lavandin cultivar (L. × intermedia ‘Budrovka’), lavandin ‘Grosso’ and one undetermined lavender sample (Lavandula sp.) showed compliance with standard requirements for lavender EO composition (contents of linalool 23.9–30.2% and 28.9–36.9%, and of linalyl acetate 22.2–32.2% and 6.9–20.7% in true lavender and lavandin samples, respectively). All EO were characterized as pleasant, with a floral aroma as a prominent odor. Samples exhibited high antimicrobial activities (3.5–14.2 µL mL⁻¹ MIC and MBC values) against important Gram-positive (B. cereus and L. monocytogenes) and Gram-negative bacteria (E. coli) and yeasts (C. albicans), and high antioxidant capacity (IC₅₀ values of 0.23–0.59 µg AAE mL⁻¹ EO). This preliminary research on the quality of lavender EOs reveals the potential of this species for the future of medicinal and aromatic plant species production and further diversification of agriculture in the area.

The aim of this study is to compare the efficacy of selected food disinfectants on planktonic populations of Staphylococcus aureus and Escherichia coli and on the same microorganisms (MOs) incorporated in a biofilm. Two disinfectants were used for treatment: peracetic acid-based disinfectant (P) and benzalkonium chloride-based disinfectant (D). Testing of their efficacy on the selected MO populations was performed using a quantitative suspension test. The standard colony counting procedure was used to determine their efficacy on bacterial suspensions in tryptone soy agar (TSA). The germicidal effect (GE) of the disinfectants was determined based on the decimal reduction ratio. For both MOs, 100% GE was achieved at the lowest concentration (0.1%) and after the shortest exposure time (5 min). Biofilm production was confirmed with a crystal violet test on microtitre plates. Both E. coli and S. aureus showed strong biofilm production at 25 °C with E. coli showing significantly higher adherence capacity. Both disinfectants show a significantly weaker GE on 48 h biofilms compared to the GE observed after application of the same concentrations on planktonic cells of the same MOs. Complete destruction of the viable cells of the biofilms was observed after 5 min of exposure to the highest concentration tested (2%) for both disinfectants and MOs tested. The anti-quorum sensing activity (anti-QS) of disinfectants P and D was determined via a qualitative disc diffusion method applied to the biosensor bacterial strain Chromobacterium violaceum CV026. The results obtained indicate that the disinfectants studied have no anti-QS effect. The inhibition zones around the disc therefore only represent their antimicrobial effect.

The aim of the present study was to investigate the chemical composition of spice EOs from the family of Lamiaceae (basil, mentha, winter savory) and Apiaceae (dill) as well as their antibacterial activity against food-borne pathogenic bacteria Escherichia coli (E. coli) and Salmonella Typhimurium (S. Typhimurium). Chemical composition of the EOs was identified by gas chromatography coupled with mass spectrometer detector (GC-MS). The results showed that linalool (in basil EO), menthol (in mentha EO), p-cymene (in winter savory EO) and carvone (in dill EO) were the main compounds. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also determined by broth microdilution method. All EOs possessed significant antibacterial effects on both tested bacterial strains. Dill EO had the highest antibacterial activity against tested bacterial strains with MIC/MBC values of 3.55 µL/mL, while mentha had the lowest antibacterial activity with MIC/MBC values of 14.20 µL/mL against E. coli and 56.81 µL/mL against S. Typhimurium. The MIC/MBC values of basil and winter savory EOs were 7.10 µL/mL for both tested bacteria. Based on the present study, the EOs from spice herbs possess antimicrobial activity against tested food-borne pathogens and thus can be a good source of natural antimicrobials agents.

Background: Fresh leafy vegetables are widely consumed because of their high nutritional value but are also recognized as important vehicles for foodborne pathogens. Escherichia coli readily attaches to lettuce surfaces and forms biofilms, enhancing bacterial persistence and reducing the effectiveness of conventional washing procedures. This study evaluated the antibiofilm activity of dill, basil, winter savory, and peppermint essential oils (EOs) against E. coli during initial bacterial attachment and against preformed biofilms on polystyrene surface and lettuce leaves. Methods: Biofilm formation was assessed using Congo Red agar, the crystal violet microtiter plate assay, and a bacterial attachment assay on lettuce leaves, while biofilm architecture and the effects of EO treatment were examined by scanning electron microscopy (SEM). Antibacterial activity was determined by the broth microdilution method, and antibiofilm activity on initial bacterial attachment and preformed biofilms was evaluated at 0.5 × MIC, MIC, and 2 × MIC using the crystal violet assay and bacterial attachment assay on lettuce leaves, respectively. Results: The examined E. coli isolates predominantly exhibited the rdar morphotype and produced stronger biofilms at 25 °C than at 37 °C. All tested EOs significantly reduced initial bacterial attachment and disrupted preformed biofilms in a concentration-dependent manner. Dill EO showed the strongest antibacterial and antibiofilm effects, followed by basil, winter savory, and peppermint EOs. At 2 × MIC, the tested EOs reduced initial bacterial attachment by 74.17–84.63%, while dill EO reduced preformed biofilm on polystyrene by 59.90% after 60 min. SEM analysis confirmed extensive disruption of biofilm architecture and pronounced morphological damage to bacterial cells following EO treatment. Conclusions: These findings demonstrate that essential oils, particularly dill EO, effectively inhibit both the establishment and persistence of E. coli biofilms on polystyrene and lettuce leaves, highlighting their potential as natural antibiofilm agents for improving the microbiological safety of fresh produce.