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Natasha Kovatcheva, Valtcho D. Zheljazkov and Tess Astatkie

Rose oil production worldwide is based on different oil-bearing Rosa species. This 4-year study determined the essential oil content, constituents, and morphologic/phenologic characteristics of 25 varieties, chemotypes, and hybrids belonging to five Rosa species (R. damascena Mill., R. gallica L., R. centifolia L., and R. alba L.). Limits of variation of these indices were established for each variety, chemotype, and hybrid group. The essential oil content of R. damascena varied from 0.032% to 0.049% and that of hybrid roses from 0.037% to 0.05%. The highest essential oil content was found in R. damascena accession Svejen 74 and the lowest in R. alba. Within R. damascena, the weight of single flowers varied from 2.09 to 3.44 g, the number of petals from 22 to 28, the height of the plants from 61 to 128 cm, and the diameter of bushes from 53 to 118 cm. R. centifolia had the largest flowers. The essential oil of the various species showed moderate to no antimicrobial activity at 50 μg/mL and no significant antibacterial, antifungal, antileishmania, or antimalarial activity at this concentration. All the tested species and accessions could be grown in Bulgaria (and possibly in southeastern Europe and the northern Mediterranean) and provide comparable productivity to the traditional species R. damascena. Wide variations occurred in essential oil content and constituents and morphologic/phenologic characteristics of the tested Rosa species and accessions. The availability of various species and chemotypes within specific species offer an opportunity for production of oil-bearing roses and essential oils to meet market requirements of specific rose oils.

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Valtcho D. Zheljazkov, Tess Astatkie, Santosh Shiwakoti, Shital Poudyal, Thomas Horgan, Natasha Kovatcheva and Anna Dobreva

Garden sage (Salvia officinalis L.) is a medicinal, culinary, ornamental, and essential oil plant with a wide range of ecological adaptation. Garden sage essential oil traditionally is extracted by steam distillation from the above-ground biomass and has widespread applications as an aromatic agent in the food and pharmaceutical industries as well as in perfumery and cosmetics. The hypothesis of this study was that the steam distillation time (DT) may significantly affect essential oil yield and composition of garden sage and, therefore, DT could be used as a tool to obtain oil with different composition. Therefore, the objective was to evaluate the effect of various steam DTs (1.25, 2.5, 5, 10, 20, 40, 80, and 160 minutes) on garden sage oil yield and composition. Most of the oil in the garden sage dry herbage was extracted in 10-minute DT; extending DT up to 160 minutes did not significantly increase oil yields. Overall, 39 oil constituents were identified in the garden sage essential oil. Fourteen oil constituents with the highest concentration in the oil were selected for statistical analyses. Monoterpenes represented the major percentage (58.2% to 84.1%) of oil composition followed by sesquiterpenes (4.0% to 16.1%) and diterpenes (0.3% to 7.6%). Overall, the monoterpene hydrocarbons (α-pinene, camphene, β-pinene, myrcene, and limonene) were eluted early in the steam distillation process, which resulted in their high concentration in the oil at 5- to 10-minute DT and relatively low concentrations in the oil obtained at 160-minute DT. In general, the concentration of sesquiterpenes (β-caryophyllene, α-humulene, and verdifloral) increased with increasing duration of the DT and reached their respective maximum concentrations in the oil at 160-minute DT. The relative concentrations of major constituents, camphor and cis-thujone, in the oil obtained at 2.5-minute DT were higher than in the oils obtained at longer DT. Therefore, if oil with high concentrations of camphor and cis-thujone is desirable, garden sage dried biomass ought to be steam distilled for 2.5 to 5 minutes and the oil collected. If oil with a high concentration of monoterpene hydrocarbons and a high concentration of oxygenated monoterpenes is desirable, then garden sage should be distilled for 20 minutes. If oil with a high concentration of the diterpene manool is desirable, then garden sage should be steam-distilled for 80 minutes. If oil with a high concentration of sesquiterpenes is desirable, then garden sage should be steam-distilled for 160 minutes. The duration of steam distillation can be used as an economical method to obtain garden sage oil with a different chemical composition. The regression models developed in this study can be used to predict garden sage oil yield and composition distilled for various amounts of time and to compare literature reports in which different durations of DT were used.