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⁻¹ d.m.) were higher than in flowers (1.13–1.14 mg g⁻¹ d.m.). Similarly, higher total contents of flavonoids were determined in leafy stalks (3.41–3.51 mg g⁻¹ d.m.), as compared with flowers (0.86–0.91 mg g⁻¹ 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 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.

In the current study, the isomerization of geraniol over a natural sepiolite as a catalyst was investigated and optimized. Prior to application in the isomerization process, the physical and chemical properties of sepiolite were characterized using a battery of instrumental techniques, including XRD, nitrogen adsorption at 77 K, SEM, EDXRF, UV–Vis and FT-IR. Results indicated that geraniol isomerization is very complicated due to the large number of reactions taking place. The catalytic studies showed that the main reaction products were β-pinene, ocimenes, linalool, nerol, citrals, thunbergol and isocembrol; all chemical products with commercial applications. The quantity of each of these products depended on the temperature, catalyst content and reaction time employed in the isomerization process. During the current study, these parameters were varied in a step-wise approach over the ranges 80–150 °C (temperature), 5–15 wt% catalyst content and reaction time of 15–1440 min. As linalool is one of the most commercially important reaction products, the geraniol isomerization method was studied to identify conditions producing the highest selectivity for this compound. The most beneficial conditions for geraniol conversion and linalool formation were established as a temperature of 120 °C, catalyst content of 10 wt% and a reaction time of 3 h. Graphic