Study of the Chemical Composition of Stachys Palustris L. Essential Oil Producing in the Astrakhan Region

Objective: The aim of this work is to study the component composition of essential oil obtained from the above-ground parts of wild-growing Stachys Palustris L. in the Astrakhan region and the dependence of the yield of essential oil on the vegetation period of the plant. Methods: Essential oil samples were obtained by hydrodistillation. The GC-MS method was used to perform a quantitative analysis of the main components of the essential oil of Stachys palustris L. in the flowering phase. The quantitative content of essential oil components was calculated from the areas of gas chromatographic peaks without using correction coefficients. Qualitative analysis was performed by comparing linear retention indices. The essential oil yield was determined in % based on the weight of air-dry raw materials. Results and Discussion: In the results, it is found that the composition of the essential oil of Stachys palustris L. turned out to be very specific. 47 compounds belonging to different classes have been identified. The main classes of compounds are fatty acids and acid esters (36.23%), carbonyl compounds (14.25%), and oxygenated sesquiterpenes (12.90%), phenols (5.85%). Among sesquiterpenoids, the predominant component of essential oil is hexahydrofarnesyl acetone (7.5%). The oil also contains (Z)-phytol (6.78%), thymol (4.2%), β-ionone (3.36%), and β-caryophyllene (2.87%). The non-specific components of the essential oil of the taxon Stachys palustris are coumarin (10.27%) and coumaran (0.36%). The highest yield of essential oil was obtained from plants in the flowering phase (0.19–0.20%). Conclusions: The work obtained data on the features of the chemical composition of the essential oil of Stachys palustris L., growing wild in the Astrakhan region, which is probably due to both its taxon species affiliation and the climatic conditions of growth and the allelopathic effect of biocenoses.