Ontogenetic and Environmental Variability of Hyssop (Hyssopus officinalis L.) Essential Oil Composition and Activity

Hyssop is an aromatic plant containing essential oil, used in folk medicine, and also known as a popular spice and ornamental plant. Hyssop essential oil is commonly used in cosmetics, perfumes, alcoholic and non-alcoholic beverages, and food additives. It can also be intended for external use as a fragrance ingredient in soaps, perfumes, creams, and other cosmetic products, as well as in aromatherapy. The composition of hyssop essential oil is not uniform and depends on a number of factors, including genetic, ontogenetic, and environmental ones. The hyssop essential oil is rich in oxygenated terpene compounds, the majority of which are represented by monoterpene ketones, i.e., isopinocamphone and pinocamphone. The essential oil yield ranged from 0.22% to 4.4% in different parts of the plant. The highest concentration of essential oil is found during full bloom. Annual plants accumulated the highest contents of volatile compounds, which was significantly influenced by genotype and year of cultivation. In addition, environmental conditions modify the composition of the essential oil of individual hyssop genotypes in different ways. Hyssop essential oil exhibits multi-faceted biological activities, depending on its chemical composition, which in turn depends on the stage of development and growing conditions.