The aim of the study was comparing the chemical composition of the essential oils from five varieties of lavender (Lavandula angustifolia L.), and its biological activity against two pathogenic bacteria, Staphylococcus aureus and Pseudomonas aeruginosa. In the comparison we included the following varieties: 'Munstead', 'Munstead Strain', 'Lavender Lady', 'Ellegance Purple' and 'Blue River'. Selected varieties of lavender (L. angustifolia) are characterised by exactly the same main compounds with only variations in the percentage of content. The primary components of the essential oils were: linalool (23.9-15.8%), linalyl anthranilate (12.3-1.6%), 1-terpinen-4-ol (9.7-5.5%), p-menth-1-en-8-ol (7.9-4.0%) and linalool oxide (4.7-1.1%). From the essential oils that were tested, the 'Blue River' and 'Munstead' varieties have the greatest antibacterial activity against S. aureus and P. aeruginosa.

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The aim of study was to compare the content of phenolic acids and flavonoids in two cultivars of Lavandula angustifolia: 'Blue River' and 'Ellagance Purple', including flowers and leafy stalks. Total phenolics and total flavonoids contents were determined by UV-Vis spectroscopy. The contents of total phenolics in leafy stalks (3.71-4.06 mg g d.m.) were higher than in flowers (1.13-1.14 mg g d.m.). Similarly, higher total contents of flavonoids were determined in leafy stalks (3.41-3.51 mg g d.m.), as compared with flowers (0.86-0.91 mg g d.m.). Phenolic acids and flavonoids were identified and quantified using HPLC and UPLC methods. Three phenolic acids were determined: rosmarinic, ferulic and caffeic acid. Lavender extracts contained also flavonoids from group of apigenin, luteolin and quercetin. Higher amounts of luteolin diglucuronide and luteolin glucuronide were found in leafy stalks in comparison to flowers. Obtained results indicate that leafy stalks of lavender can be also valuable source of antioxidant compounds.

The less-volatile compounds forming a smoke emitted during the thermal degradation of poly(ethylene terephthalate) (PET) in different conditions were studied. Thermal degradation of PET was carried out within the temperature range of 200-700°C in both a nitrogen and an air atmosphere. The less-volatile thermal degradation products were trapped on a glass-fiber filter and analyzed by capillary gas chromatography with mass selective detector (GC-MS) and high performance liquid chromatography (HPLC). The results are collected in tables and presented on plots as a function of the degradation temperature. The temperature and atmosphere effects on the emission and composition of the smoke during PET thermal degradation were considered.

S u m m a r yIntroduction: Staphylococcus aureus is an important etiological agent of skin and soft tissue infections. Due to the increasing resistance of this bacterium to antimicrobial agents, treatment of staphylococcal infections remains a great challenge for clinicians and requires an alternative treatment options. Objective: The aim of the study was to determine the antimicrobial activity of essential oils: caraway (CEO), patchouli (PEO) and geranium (GEO) against S. aureus strains isolated from skin lesions in the course of staphylococcal skin infections. Methods: The antibacterial activity of essential oils was tested using the dilution method in Mueller-Hinton broth. Results: The antimicrobial effect of CEO, PEO and GEO was observed. The highest antimicrobial activity showed PEO (MIC = 1.7±0.8 μl/ml), the lower was observed for GEO (MIC = 5.4±2.0 μl/ml) and CEO (MIC = 18.8±10.3 μl/ml). Conclusion: All tested essential oils showed antibacterial activity against S. aureus strains isolated from skin lesions of patients with staphylococcal skin infections. Application of the CEO, PEO and GEO can become an alternative method of treatment of staphylococcal infections, but further microbiological tests and clinical trials should be assessed. key words: Staphylococcus aureus, caraway oil, patchouli oil, geranium oil, staphylococcal skin infections