Essential oil constituents of Juniperus oxycedrus L. and Cupressus sempervirens L. (Cupressaceae) growing in Aures region of Algeria.

The purpose of this study was to determine the chemical composition of essential oils from the aerial parts of two species belonging to the Cupressaceae family growing in the Aures region of Algeria Juniperus oxycedrus and Cupressus Sempervirens. The analysis by GC-MS and GC-FID techniques showed the presence of 38 compounds in J. oxycedrus oil where the major constituents were manoyl oxide (23.5%), pentadecan-2-enone 6Z (12.6%), abietatriene (8.0%), abieta-8,11,13-triene-7-one (6.5%), cubebol (4.6%), epi-torilenol (3.8%) and α-cadinol (2.6%), while, a total of 65 compounds were showed in C. sempervirens oil where the major constituents were α-pinene (68.0%), epi-cedrol (6.1%), α-terpenyl acetate (3.5%) and germacrene D (2.5%). It is the first time that the compounds pentadecan-2-enone 6Z, abieta-8,11,13-trien-7-one, cubebol and epi-torilenol have been identified in our J. oxycedrus and epi-cedrol in C. sempervirens essential oils with high contents, as we noticed the absence of α-pinene in our J. oxycedrus essential oil.

Aromatic Plants from Plateau des Cataractes: Occurrence of the Citronella Chemotype of Cymbopogon flexuosus (Nees ex Steud.) W.Watson Acclimatized in Congo-Brazzaville.

Cymbopogon flexuosus var. flexuosus (citral chemotype) was introduced in a local plantation in 2006 at Plateau des Cataractes, Congo-Brazzaville to remedy the difficult adaptation and low production of essential oil of C. citratus, a source of citral. After some 10 years of acclimatization, C. flexuosus had adapted perfectly with a very high biomass and essential oil production. A citronella chemotype (Cymbopogon flexuosus var. albescens) was unexpectedly identified among lemongrass in the field, grown in a local experimental citronella plot covering 0.25 ha. Its essential oil was extracted by hydrodistillation and analyzed by GC and GC/MS to determine its chemotype. The citronella chemotype indicated by the chemical profile found was confirmed by descriptive statistics (radar plot) and by principal component analysis (PCA) and ascending hierarchical clustering (AHC).

The effect of harvest periods on the chemical compositions of essential oils of sage (Salvia aucheri L.) leaves.

The essential oils of sage leaves (Salvia aucheri Bentham var. canescens Boiss. & Heldr.), growing wild in South Anatolia, were extracted by hydrodistillation and analysed by GC and GC-MS. The percentage yields of the essential oils from sage leaves harvested at different years were 1.0%, 1.3%, 1.3%, 1.0%, 1.4%, 1.5% and 1.2%, respectively. In this study, 1,8-cineole, camphre, camphene α-pinene and ß-pinene were identified as the major components of sage leaves collected at different periods. The main constituents of sage oil collected over the years were 1,8-cineole (35.01-48.06%), camphre (13.58-23.92%), camphene (6.77-8.82%), α-pinene (5.79-8.54%) and ß-pinene (4.32-6.28%).

Chemical variability of essential oils in natural populations of Cupressus dupreziana.

Essential oils extracted from dried leaves of Cupressus dupreziana A. Camus, an endemic species in the Tassili n'Ajjer (Central Sahara of Algeria), were analyzed by gas chomatography coupled to mass spectrometry (GC-MS). Analyses were carried out on 164 trees of 26 natural populations in order to determine the intra-specific variability. Thirty-two terpenoids were identified, the major ones being alpha-pinene (11.5-44.2), delta3-carene (5.7-31.7) and germacrene-D (15.7-54.1). The terpenoid markers used made it possible to determine the individual patterns of chemotypic variability. This variability confirmed that genetic factors were not responsible for the decrease in the number of this species, the main reason probably being the Tassili n'Ajjer desertification.

Chemical composition and antimicrobial activity of essential oils of Genista ulicina and G. vepres.

The hydrodistilled oils from the aerial parts of Genista ulicina Spach. and G. vepres Pomel., which are endemic to Algeria, were analyzed by gas chromatography-mass spectrometry (GC-MS). In the oil of G. ulicina, 41 compounds were identified representing 90.8% of the total oil, and in G. vepres, 61 compounds representing 84.5% of the total oil. The analyses showed that the major constituents of the oils were lauric acid (14.3%-8.5%), myristic acid (11.5%-5%), linoleic acid (3.1%-11.7%) and palmitic acid (18.6%-26.4%). Using a diffusion method, the oils showed significant antibacterial activities against Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus aureus (ATCC 25923).

Chemical composition and antifungal activity of rosemary (Rosmarinus officinalis L.) oil from Turkey.

The essential oil of the aerial parts of Rosmarinus officinalis collected from Konya, Turkey was analysed by gas chromatography and gas chromatography-mass spectrometry. The oil yield of dried plant (volume/dry weight) obtained by hydrodistillation was 1.9%. Twenty compounds representing 99.93% of the oils were identified. The main constituents of the oils were p-cymene (44.02%), linalool (20.5%), gamma-terpinene (16.62%), thymol (1.81%), beta-pinene (3.61%), alpha-pinene (2.83%) and eucalyptol (2.64%). The oil consisted of monoterpenic hydrocarbons, oxygenated monoterpenes and sesquiterpene hydrocarbons. Also, the inhibition effect of rosemary oil was investigated against Alternaria alternata, Botrytis cinerea and Fusarium oxysporum. The experiment was carried out in vitro using disc diffusion to investigate the antifungal action of the oil. Oil tested on potato dextrose agar plates exhibited an inhibitory effect. The extent of inhibition of fungal growth varied depending on the levels of essential oil used in experiment.

Comparative essential oil composition of flowers, leavesand stems of basil (Ocimum basilicum L.) used as herb.

The chemical composition of flower, leaves and stems from basil (Ocimum basilicum L.) have been examined by GC and GC-MS. The identified components constituting 99.03%, 95.04% and 97.66% of the flower, leaves and stem oils, respectively. The main constituents of the essential oil of flower, leaves and stem oils, respectively, were estragole (58.26%, 52.60% and 15.91%) and limonene (19.41%, 13.64% and 2.40%) and p-cymene (0.38%, 2.32% and 2.40%). Dill apiole (50.07%) was identified as the highest main constituent for stem. Estragole (15.91%), apiole (9.48) and exo-fenchyle acetate (6.14%) followed in order to decreasing them. Minor qualitative and major quantitative variations for some compounds of essential oils were determined with respect to different parts of O. basilicum. It was reported that the chemical composition of different parts oils of basil are very variable. It is known that specific estragole chemotypes are also known.

Comparative essential oil composition and antifungal effect of bitter fennel (Foeniculum vulgare ssp. piperitum) fruit oils obtained during different vegetation.

The chemical composition of the flower and unripe and ripe fruits from fennel (bitter) (Foeniculum vulgare ssp. piperitum) has been examined by gas chromatography and gas chromatography-mass spectrometry. The main identified components of the flower and unripe and ripe fruit oils were estragole (53.08%, 56.11%, and 61.08%), fenchone (13.53%, 19.18%, and 23.46%), and alpha-phellandrene (5.77%, 3.30%, and 0.72%), respectively. Minor qualitative and major quantitative variations for some compounds of essential oils were determined with respect to the different parts of F. vulgare. The oils exerted varying levels of antifungal effects on the experimental mycelial growth of Alternaria alternata, Fusarium oxysporum, and Rhizoctonia solani. The 40 ppm concentrations of fennel oils showed inhibitory effect against mycelial growth of A. alternaria, whereas 10 ppm levels were ineffective. The analyses show that fennel oils exhibited different degrees of fungistatic activity depending on the doses.

Effect of different locations on the chemical composition of essential oils of laurel (Laurus nobilis L.) leaves growing wild in Turkey.

The essential oil components of Laurus nobilis gathered from seven different locations of Turkey were identified by gas chromatography/mass spectrometry. The oil yields on a dry weight basis ranged between 1.4% to 2.6%. The major component was 1,8-cineole (51.73-68.48%); other predominant components were alpha-terpinyl acetate (4.04-9.87%), sabinene (4.44-7.75%), alpha-pinene (2.93-4.89%), beta-pinene (2.58-3.91%), terpinene-4-ol (1.33-3.24%), and alpha-terpineol (0.95-3.05%). Minor qualitative and major quantitative variations of some compounds were determined with respect to localities of collection. As a result, the 1,8-cineole content of these oils was significantly higher than those of other constituents of L. nobilis. Laurel is usually considered as the natural source of this compound, used in the flavor and fragrance industry.

Qualitative and quantitative variation in monoterpene co-occurrence and composition in the essential oil of Thymus vulgaris chemotypes.

Thymus vulgaris has a chemical polymorphism with six different chemotypes that show marked spatial segregation in nature. Although some populations have a single chemotype in majority, many have two or three chemotypes. In this study we analyze the quantitative variation among T. vulgaris populations in the percentage of oil composed of the dominant monoterpene(s) for each chemotype. In general, phenolic chemotypes (thymol and carvacrol), which occur at the end of the biosynthetic chain, have a significantly lower proportion of their oil composed of their dominant monoterpene than nonphenolic chemotypes (geraniol, alpha-terpineol, and linalool). This is due to the presence of high amounts of precursors (gamma-terpinene and paracymene) in the oil of phenolic chemotypes. The essential oil of the nonphenolic thuyanol chemotype has four characteristic monoterpenes that together make up a lower proportion of the oil than the single dominant monoterpene of the other nonphenolic chemotypes. For all chemotypes, the percentage composition of the dominant monoterpene decreased significantly at sites where the chemotype is not the majority type. This decrease is correlated with a significant increase in either the proportion of the two precursors for the thymol chemotype or the monoterpenes characteristic of the other chemotypes at the site. The latter result suggests that a plant with dominant genes is responsible for the production of different monoterpenes can produce several molecules.