Comparison of qualitative and quantitative chemical composition of hydrolate and essential oils of lavender (Lavandula angustifolia)

The chemical composition of essential oils and hydrolate from dried lavender flowers (Lavandula angustifolia) was determined. Organic compounds were isolated from the hydrolate by the liquid-liquid (LLE) method. Optimal conditions for LLE (pentane, five extraction cycles, 40 mL, salting out [5% NaCl]) were determined by the Taguchi method. As many as forty-seven compounds were identified both in the essential oil (Oe) and in the essential oil isolated during the preparation of hydrolate (OeH), representing 94.9% of the content of Oe and 95.7% of OeH. The main compounds in OeH and Oe are: linalool (24.6% and 24.9%, respectively), linalyl acetate (14.4% and 18.0%, respectively) and borneol (6.2% and 6.3%, respectively). The most abundant compounds are oxygenated derivatives of monoterpenes (74.3% Oe, 73.4% OeH), including monoterpene alcohols (40.5% Oe, 38.0% OeH). In the hydrolate (H), twenty-four compounds, representing 83.8% of its composition, were identified. The main ingredients are: linalool (26.5%) and borneol (9.0%). Also here, oxygenated derivatives of monoterpenes predominate (78.1%), consisting mainly of alcohol monoterpenes (50.7%). In the hydrolate, the presence of acetate linalyl, monoterpenes, or sesquiterpenes was not found. Quantitative analysis of Oe, OeH and H was conducted for selected chemical compounds.