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Sideritis montana subsp. montana is a small annual herb occurring in countries bordering the Mediterranean and Balkan regions. The secondary metabolism of this plant has not been fully explored so far. The aim of the present study was to understand the complex mixture of secondary metabolites and the type of secretory structures. The polar constituents were isolated by column chromatography from the ethanolic extract, and their structure was elucidated by NMR and MS. The essential oil was isolated by hydrodistillation and analysed by GC/MS. The plant indumentum was studied by light and scanning electron microscopy. To complete the work, the essential oil antioxidant activity and cytotoxicity on tumor cells were evaluated by DPPH, ABTS, FRAP, and MTT methods. Four different classes of secondary metabolites were isolated, namely flavonoids, caffeoylquinic derivatives, glycosidic hydroquinones and iridoids. The essential oil was mainly characterized by sesquiterpenene hydrocarbons. Peltate and long-capitate hairs were the main sites where terpenes and polar constituents are produced. The secondary metabolites found in S. montana subsp. montana are of chemotaxonomic interest, some of them being typical of the genus Sideritis. The trichomes types observed partially differ from those described in other members of the genus Sideritis. The essential oil showed noteworthy inhibition on tumor cells.

Hypericum androsaemum , also known as Tutsan, produces fleshy and berry-like fruits that ripen from red to shiny black. The essential oil and aroma components of the red and black berries were investigated by GC–FID, GC–MS, and HS-SPME–GC–MS. The nutritional profile of the red and black berries in terms of proteins, carbohydrates, crude fiber, ascorbic acid, mineral content and fatty acid composition was also investigated. Finally, the morphological and histochemical study of fruits identified the histolocalization of the complex metabolite mixture produced. Results showed that monoterpene hydrocarbons gave the major contribution to the fruit aroma, with limonene as the most representative compound, even though some differences were found between red and black berries. Nutritional analysis highlighted a relevant content of ascorbic acid (135.7 mg/100 g) in red berries. The morphological and histochemical analysis showed that the fruit secretion is produced in numerous translucent glands that originated from the ovarian mesophyll and arranged in concentric rings.

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.

Octen-3-ol is the most important C8 mushroom aromatic compound produced by many species of edi- ble fungi and is also an aroma component in several food and beverages products. Under this view, the essential oil of flowering aerial parts of Melittis melissophyllum subsp. melissophyllum (Lamiaceae) grow- ing in central Italy, obtained by hydrodistillation was characterised by GC-FID and GC-MS. This oil con- tained extremely high amount of the mushroom-like aroma component 1-octen-3-ol (43.6-54.2%), and could be considered as a new natural product for the use as flavouring agent in the food industry. Further- more, headspace analysis suggested that this aromatic compound is only present in low concentration in the plant part, and is primarily formed in higher amount during hydrodistillation of this material.

Stachys alopecuros subsp. divulsa (Lamiaceae), a perennial herb endemic to central Italy growing on mountain pastures, was investigated for the first time for the content of secondary metabolites, for the micromorphology and histochemistry of glandular trichomes, and for the biological activity of the volatile oil, namely cytotoxic, antioxidant and antimicrobial. The plant showed the molecular pattern of iridoids, among which a new iridoid diglycoside (4′- O -β- d -galactopyranosyl-teuhircoside) was detected, together with a sterol glucoside and a phenylethanoid glycoside. The essential oil from the flowering aerial parts was characterized by a high proportion of sesquiterpene hydrocarbons (65.1%), with ( E )-caryophyllene (33.2%) as the most abundant, while other main components were germacrene D (7.6%), α-humulene (6.4%) and the oxygenated cis -sesquisabinene hydrate (10.2%). Taken together, polar and apolar chemical profiles support the classification of the species within the section Betonica of the genus Stachys . Micromorphological study revealed three types of glandular hairs secreting different classes of compounds, with type A peltate hairs producing the bulk of the essential oil. MTT assay revealed the potential of the volatile oil in inhibiting A375, HCT116 and MDA-MB 231 tumor cells (IC 50 values below 20 μg/ml).

Ferula glauca L. (Apiaceae), formerly believed a subspecies of Ferula communis L., but at the present considered a distinguishable species, was studied for the first time for volatiles from leaves, flowers, fruits and roots. The chemical analysis of the essential oil obtained from different populations growing in Marche (central Italy) was performed by GC-FID and GC–MS. The differences in composition detected between F. glauca and F. communis made the volatile fraction a reliable marker to distinguish between them, and confirmed the botanical data at the base of their discrimination. In particular, the oils obtained from leaves and roots, contained as major compounds (E)-caryophyllene, caryophyllene oxide, myristicin and elemicin, that can be useful as marker components. Finally, the oils contained some daucane derivatives, that were detected also in F. communis and responsible for important biological properties.

The essential oil of Ephedra nebrodensis Tineo ex Guss. subsp. nebrodensis growing in central Italy was analyzed for the first time by GC and GC/MS. Fifty-nine components were identified, representing 89.3% of the oil under study. The oxygenated monoterpenes gave the highest contribution (33.0 %), and citronellol (29.7%) was the main component of this fraction. Esters were the second most abundant group of components (18.8%) with ethyl hexadecanoate (9.5%) as the main representative in this fraction. Qualitative and quantitative composition of the oil was discussed in order to support the actual botanical discrimination from E. major Host, so far exclusively morphologically based.