ABSTRACT
Sideritis italica (Mill.) Greuter et Burdet belongs to the Lamiaceae family and is endemic to Italy. The glandular trichomes (morphology, distribution, histochemistry, and ultrastructure) of the plant were studied for the first time, along with the chemical composition of the essential oils. Abundant non-glandular hairs and peltate (type A) and capitate (types B, C(1), and C(x)) glandular trichomes were observed both on the vegetative and reproductive organs. The histochemical procedures and the ultrastructural investigation enabled specific location of the main site of essential oil production mainly in type-A peltate hairs. Particular emphasis is given to the release mechanism of the secreted material in all of the types of glands, and the potential taxonomic value of the indumentum in the Lamiaceae family is briefly discussed. Essential oils were hydrodistilled from flowering aerial parts of S. italica, and 136 compounds (112 in flowerheads, 79 in vegetative parts) were identified. The quantitative prevalence of diterpenoids (43.4% in flowerheads and 22.3% in vegetative parts) was the most significant characteristic of the essential oil of S. italica that could be classified as a diterpene-rich essential oil according to the classification of Kirimer.
Subject(s)
Oils, Volatile/isolation & purification , Plant Components, Aerial/chemistry , Plant Oils/isolation & purification , Sideritis/chemistry , Italy , Microscopy, Electron, Scanning , Oils, Volatile/chemistry , Plant Components, Aerial/growth & development , Plant Components, Aerial/ultrastructure , Plant Oils/chemistry , Sideritis/growth & development , Sideritis/ultrastructureABSTRACT
The essential oils from both leaves (L) and flowers (F) of Stachys germanica subsp. salviifolia (Ten.) Gams (Labiatae/Lamiaceae) from Italy were analyzed by GC-MS for the first time. The distribution, morphology and histochemistry of the different types of glandular trichomes present on the epidermal surface were also determined. Twenty-nine constituents, representing 89.4% of the total leaf oil, and forty-one compounds, forming 97.8% of the total flower oil, were identified. Germacrene D (39.4%), phytol (10.2%), beta-bourbonene (3.5%) and beta-ylangene (3.3%) were recognized as the main constituents of the leaf essential oil, while limonene (24.1%), beta-pinene (18.7%), germacrene D (12.8%) and (E)-nerolidol (6.6%) were the main compounds of the flower essential oil.