Search

Aiming to find out if any distinction between the Greek (Origanum vulgare ssp. hirtum) and Turkish oregano (O. orates) essential oils exists, the composition of six wild Greek populations of the former and four of the latter taxon were analyzed by means of GC and GC/MS. A PCA analysis showed that Turkish oregano oils had higher amounts of sabinene, myrcene, γ-terpinene, borneol and carvacrol, and Greek oregano oils had higher p-cymene content. The latter were further divided into two subgroups, distinguished respectively by their thymol and carvacrol content. A comparison of our results with the published information showed that p-cymene percentages > 14% and/or thymol > 6% is found only in Greek oregano, while borneol content > 2% is found only in Turkish oregano oils. [ABSTRACT FROM AUTHOR]

Abstract: The study of essential oils obtained from Coridothymus capitatus and Satureja thymbra collected from different natural habitat types of 11 NATURA 2000 sites scattered all over Crete has shown that they are characterized either by a high amount of carvacrol (up to 75.7%) or thymol (up to 65.6%) or by a more or less equal amount of the two phenols. The results of a discriminant analysis with predefined groups the natural habitat types wherefrom the plants were collected have shown that the oils of both species collected from the dry dwarf-shrub formations of the lowland have a high carvacrol content whereas those collected from the more mesic timber or highland formations have a high thymol content. Furthermore, the results of this study introduce the use of natural habitat unit as a tool for the assessment of essential oil variation. [Copyright &y& Elsevier]

Abstract This is the first account of the essential oils of wild Greek plants of Thymbra spicata , an East Mediterranean species used as a culinary herb and herbal tea. In particular, the yield and composition of the essential oil of Th. spicata from Chios Island is recorded and compared between two seasons. Considering that Chios provides the westernmost studied material of Th. spicata , the geographical variation in the main essential oil compounds in the total natural range of the species in relation to its systematics is also discussed. The essential oil yield of the Chios plants ranged from 2.4 to 4.8 mL 100 g−1 dry weight (aerial parts without stems). Carvacrol (responsible for the “oregano” scent) was dominant in considerably high amounts (67.5%–88.3% of the total oil) and without significant seasonal differences. Other main compounds were p -cymene (0.7%–17.4%), γ-terpinene (0.1%–6.9%) and caryophyllene oxide (0.9%–2.5%). Τhymol (responsible for the “thyme” scent) was always very low (0.3%–0.7%). Throughout the East Mediterranean, carvacrol is dominantly the major essential oil compound of Th. spicata. p -Cymene, γ-terpinene and other, more minor, compounds contribute to local differences in the species' essential oils in its total range. The thymol-chemotype is scarce throughout the species' range and not related to the local Turkish subspecies intricata as previously suggested. Despite the closer taxonomic affinities with the genus Thymus and the thyme-related vernacular names attributed to Th. spicata , this species can be characterized as an “oregano” with regard to its essential oil composition and herbal use. Highlights • The essential oil yield of Thymbra spicata from Chios Island is 2.4%–4.8%. • Carvacrol dominates the essential oils of Th. spicata in Chios up to c. 88%. • The carvacrol-chemotype (“oregano scent”) dominates in the species' total range. • The thymol-chemotype (“thyme” scent) is scarce in the species' total range. • The thymol-chemotype is not related to subsp. intricata. [ABSTRACT FROM AUTHOR]

Oregano herbs have wide culinary uses and industrial applications due to the high antioxidant and other activity of their main essential oil compound, carvacrol. Among the oregano herbs, Origanum onites (known as “Turkish oregano”, “Island oregano” or “Cretan oregano”) is a narrowly distributed East Mediterranean species occurring mainly in Turkey and Greece, which comprises one of the major herbs of the oregano trade worldwide. We examine the essential oils of O. onites plants collected from 42 localities scattered along the total range of the species on Chios, a Greek island bordering with the Turkish mainland. We focus on the essential oil yield and five oil compounds, namely carvacrol, thymol, borneol and the biosynthetic precursors of the first two, i.e., p -cymene and γ-terpinene, in relation to the habitat type, geological substrate, altitude, bioclimatic area and geographical location, where the collected plants were growing on the island. We also discuss our results in relation to the essential oil based distinction between O. onites and another commercially important East Mediterranean oregano herb, namely O riganum vulgare subsp. hirtum (known as “Greek oregano”). The determined essential oil yield (3.0–7.0 mL/100 g of dry leaves and inflorescences) and carvacrol content (69.0–92.6%) of the examined O. onites plants from Chios are among the highest reported for this species. The essential oil yield and the content of the five compounds were not found to vary in relation to the different environmental factors examined. These findings let us conclude that the wild oregano of Chios is a valuable natural resource with a high potential for industrial use, due to its high essential oil yield and carvacrol content, that are not influenced by environmental conditions. Moreover, based on our results and recent literature we conclude that O. onites can be distinguished from O. vulgare subsp. hirtum based on the relative content of carvacrol, thymol, borneol and p -cymene – primarily borneol – in the two taxa’s essential oils, a useful means of distinction when the botanical identity of fragmented commercial oregano products is questioned. [ABSTRACT FROM AUTHOR]

Abstract: Satureja pilosa Velen. subsp. origanita Dardioti & Kokkini, is a recently described endemic taxon of NE Greece (Thrace). Its epithet reflects the prominent odor of the plants, due to which it is used by the local people as an “oregano” herb. However, the study of 19 populations scattered along the taxon’s range, revealed that the plants are characterized by a variety of odors. In particular plants from 10 populations, having essential oils rich in carvacrol (up to 62.3% of the total oil), emitted an “oregano” odor, while plants from seven populations, with oils rich in p-cymene (up to 49.8%) and/or thymol (up to 48.1%) had a “thyme” odor; the plants from the other two populations, with linalool-rich oils (59.2 and 82.7%) had a prominent “lavender” odor. A discriminant analysis with pre-defined groups the bioclimatic zone wherefrom the plants were collected has shown that the essential oil content and the amount of carvacrol gradually decrease from the Mesomediterranean to the Temperate Axeric bioclimates, while the amounts of p-cymene, thymol and linalool, increase. Our results, supported by similar findings concerning East Mediterranean taxa traded as “oregano”, have shown that in order to characterize a herb as “true oregano”, the plant odor, reflecting the oil composition, as well as the collection areas of the plants should be taken into account. [Copyright &y& Elsevier]