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International audience; Essential oils of three Lebanese Rose species (Rosa corymbifera Borkh., Rosa Phoenicia Boiss. and Rosa damascena Mill.) were investigated, to assess their bioactive components after hydrodistillation, using a Clevenger-type apparatus. A GC/MS analysis of the oil content of Rose species led to the identification of 22, 46 and 30 components in each of R. damascena, R. corymbifera and R. Phoenicia, respectively, representing 83.4 %, 72.9 % and 84.7 % of the total EO of the corresponding Rose species. The EOs chemical profile analysis showed that the main components of R. corymbifera (heptacosane (14.8 %), tricosane (10.6 %), pentacosane (8.6 %), nonacosane (8.6 %) and heneicosane (5.6 %)) and of R. Phoenicia (heptacosane (17.1 %), tricosane (12 .9 %), heneicosane (12.3 %), docosane (12.1 %) and cycloeicosane (7.6 %)) were hydrocarbons. While hydro- carbons were also identified in R. damascena (nonadecane (12.4 %) and heneicosane (8.1 %)), they were not its most abundant constituents. The major component of R. damascena was phenethyl alcohol (28.5 %), a benzenoid compound, also identified in R. phoenicia (5.1 %). Moreover, an oxygenated terpene (beta-citronellol (13.2 %)) was also identified in R. damascena. Since R. damascena is largely cultivated in Lebanon, a comparative study of R. damascena EO was performed on a group of samples collected from different locations (ours and data previously published), to identify the presence of any chemical polymorphism according to the geographical location. GC/ MS analysis together with principal component analysis (PCA) highlighted six different chemotypes for R. damascena EO: citronellol, geraniol, nerol, nonadecane, phenyl ethyl alcohol and heneicosane. This chemical variability suggests the involvement of abiotic and biotic factors that need to be further investigated.

Gas chromatography–mass spectrometry analysis together with principal component analysis revealed that geographical origin influenced the yield and composition of the essential oils (EOs) extracted by hydrodistillation performed for 3 h using a Clevenger-type apparatus, from the cones of Cedrus libani A. Rich., growing wild at four Lebanese natural reserves and protected areas: Bsharri, Chouf, Ehden, and Tannourine, and from a cultivated cedar growing in Qartaba. Essential oil chemical variability established between the different studied provenances suggested the involvement of abiotic factors such as geographical conditions, cultivation conditions, soil composition, and environmental factors in the chemical polymorphism of C. libani cones EOs. α-Pinene/β-pinene characterized Ehden (β-pinene 35.6%/α-pinene 27.7%), Chouf (α-pinene 37.3%/β-pinene 26.1%), Bsharri (α-pinene 27.7%/β-pinene 21.4%), and Tannourine (α-pinene 25.1%/β-pinene 16.0%) samples, whereas Qartaba EO was distinguished by the dominance of myrcene (30.6%), α-pinene(26%), and limonene (14.1%). Comparison with the existing literature reinforced the chemical variability of C. libani EOs. This current study helped the estimation of a best harvest location for a good EO quality production, resource optimization, and pharmacological properties evaluation, according to the market demand.

Origanum ehrenbergii Boiss., an endemic plant to Lebanon, is widely acknowledged in Lebanese traditional medicine. The aim of the present study was to evaluate the influence of the drying method, region, and time of harvest on yield and chemical composition of O. ehrenbergii essential oils (EOs). Plants were harvested monthly throughout 2013 and 2014, from two different regions, Aabadiye and Qartaba, then dried using two drying methods: lyophilization and shade-drying at 4 &deg, C. EO was extracted by hydrodistillation and analyzed by GC/MS. GC-MS data, combined with independent component analysis (ICA) and common component and specific weight analysis (CCSWA), showed that drying techniques, region of harvest, and soil composition have no effect on the chemical composition of O. ehrenbergii EOs. Of the factors analyzed, only harvesting time affected the EO composition of this species. High and stable amounts of carvacrol, associated with reliable antimicrobial activities, were detected in material harvested between March and October. EOs obtained from plants harvested in Aabadiye in January and February showed high amounts of thymoquinone, related to anti-inflammatory and cytotoxic effects. The use of ICA and CCSWA was proven to be efficient, and allowed the development of a discriminant model for the classification of O. ehrenbergii chemotype and the determination of the best harvesting time.

Background: Origanum syriacum L. is an aromatic plant growing wild in Lebanon. This species is highly used in Lebanese traditional medicine and is a staple food in Lebanese gastronomy. Due to the over-harvesting, this species has become a cultivated crop rather than being collected from the wild. This study aims to evaluate the chemical polymorphism according to soil type. Methods: Plant samples were cultivated in different soil types including manure, potting mix, professional agriculture mixture, vegetable compost, nursery soils, and natural agricultural soil inoculated with arbuscular mycorrhizal fungi. After 16 weeks of culture, fresh shoot biomass was measured. Root colonization rate was evaluated and foliar biomasses were used for essential oil (EO) extraction. EO yield was calculated and the identification of the main chemical compounds of EO samples was performed by gas chromatography (GC) and gas chromatography&ndash, mass spectrometry (GC/MS). Results: Our findings revealed that the soil type affects the O. syriacum chemotype. Indeed, the EO samples could be divided into two groups: thymol chemotype group including manure and vegetable compost soils and non-sterilized non-inoculated EO samples, and the thymol/carvacrol chemotype including potting mix, professional agriculture mixture, nursery mixture, sterilized non-inoculated, non-sterilized inoculated, and sterilized inoculated EO samples. These results showed that manure and vegetable compost soils promoted thymol synthesis, whereas potting mix, professional agriculture mixture, and nursery mixture soils were thymol/carvacrol chemotype. Moreover, mycorrhizal inoculation increased carvacrol and reduced thymol productions in comparison to non-inoculated conditions. Additionally, mycorrhizal inoculation showed significant enhancements in mycorrhizal rates and shoot biomass production with respect to the non-sterilized soil. Conclusions: These variations confirm the influence of the edaphic conditions on the chemical components biosynthesis pathways of oregano plants. The results of this investigation could be used for determining optimal soil type, leading to a good quality herb production.

International audience; Salvia fruticosaa perennial aromatic plant, endemic to the Mediterranean region, is the most used medicinal plant in Lebanon. S. fruticosa essential oils (EOs) are widely acknowledged in the Lebanese traditional medicine to treat several ailments. Plant samples were harvested at various months of the year 2013, from 4 different Lebanese areas: Baabda, Ansariyeh, Harissa and Nahr Ibrahim. Fresh herb was either air dried or lyophilized. EOs were obtained using 2 extraction techniques: Solvent-Free Microwave Extraction (SFME) and conventional hydro distillation. The chemical variability of Lebanese S. fruticosa EO quantity and quality was assessed according to harvesting time and region, drying methods and EO extraction techniques. GC/MS showed that the major compounds in the oils were: eucalyptol (18.3-83.7 %), trans-anethole (0.00-61.7 %), beta-caryophyllene (0.00-38 %), and camphor (0.00-16.7 %). EO yields were affected by plant's growth stages, drying methods and EO extraction techniques. EO extraction methods and harvesting time and region had an impact on EO chemical composition whereas tested drying methods had no significant influence. Our study highlighted 4 different chemotypes for S. fruticosa EO: eucalyptol, camphor, alpha-thujoneand trans-anethole. For the first time in our study, trans-anethole was found as distinguishable chemotype.

International audience; The essential oils obtained from Origanum libanoticum Boiss., a plant endemic to Lebanon, were analyzed by GC/MS. Seventy compounds were identified, covering till 99.8% of the total oil composition. All samples were p-cymene and/or beta-caryophyllene chemotype, with variable percentage of other compounds such as alpha-pinene, myrcene, a-phellandrene, limonene, etc. Compared to traditional drying method, lyophilized samples provided the highest essential oil (EO) yields and yields were higher at flowering stage (Chouwen: 0.33% in 2013 and 0.32% in 2014; Qartaba: 0.27% in 2013 and 0.37% in 2014). According to independent components analysis (ICA), date and site of harvest, altitude and drying technique had no effect on the variation of O. libanoticum EO, chemical composition. An annual variation of EOs composition was observed since a particular variation in some major components concentration was revealed monthly and annually between 2013 and 2014.

International audience; AbstractThis study deals with the variation in the yield and composition of Lebanese Origanum syriacum L. essential oil (EO) according to harvesting time, drying methods used, and geographical location. Plant material was harvested twice a month all over 2013 and 2014 from Qartaba and Achkout located at high altitude and from Byblos at low altitude. EOs of the aerial parts were obtained by hydrodistillation. The highest yields were obtained at full flowering stage and slightly reduced after flowering. The GC/MS analysis revealed the presence of 50 components representing 90.49 – 99.82%, 88.79 – 100%, and 95.28 – 100% of the total oil extracted from plants harvested from Qartaba, Achkout, and Byblos, respectively. The major components in the oils were: carvacrol (2.1 – 79.8%), thymol (0.3 – 83.7%), p‐cymene (2.8 – 43.8%), thymoquinone (0.4 – 27.7%), γ‐terpinene (0.4 – 10.0%), octan‐3‐ol (0.3 – 4.9%), caryophyllene oxide (0.2 – 4.7%), oct‐1‐en‐3‐ol (0.3 – 3.7%), β‐caryophyllene (0.7 – 3.2%), cis‐sabinene hydrate (0.1 – 2.8%), terpinen‐4‐ol (0.1 – 2.8%), and α‐terpinene (0.2 – 2.2%). Independent components analysis (ICA) revealed that two groups were discriminated, reflecting compositional differences in the EOs profiles of the Lebanese oregano samples: O. syriacum grown in Qartaba and Achkout belongs to carvacrol chemotype, while O. syriacum grown in Byblos belongs to thymol chemotype. The flowering phase was the most productive period in terms of yield, bringing marked changes in the EO composition by increasing the amounts of carvacrol or thymol, and decreasing those of thymoquinone and p‐cymene.