Biocidal Potential and Chemical Composition of Industrial Essential Oils from Hyssopus officinalis,Lavandula × intermedia var. Super,and Santolina chamaecyparissus

This work presents the biocidal (insecticidal, ixodicidal, nematicidal, and phytotoxic) effects and chemical compositions of three essential oils obtained from the industrial steam distillation (IEOs) of hyssop (Hyssopus officinalis L.), lavandin (Lavandula × intermedia or L. × hybrida var. Super ), and cotton lavender (Santolina chamaecyparissus L.). Their chemical composition analyzed by gas chromatography coupled to mass spectrometry showed 1,8‐cineole (53%) and β‐pinene (16%) as the major components of H. officinalis, linalyl acetate (38%) and linalool (29%) of L. × intermedia; and 1,8‐cineole (10%) and 8‐methylene‐3‐oxatricyclo[5.2.0.0^2,4]nonane (8%) in S. chamaecyparissus. The biocidal tests showed that L. × intermedia IEO was the most active against the insect Spodoptera littoralis and toxic to the tick Hyalomma lusitanicum, IEO of H. officinalis was strongly active against S. littoralis, and finally, S. chamaecyparissus IEO was a strong antifeedant against the aphid Rhopalosiphum padi, toxic to H. lusitanicum and with moderate effects against Leptinotarsa decemlineata, S. littoralis, and Lolium perenne.     

Effect of oleocellosis,desiccation, and fungal infection upon the terpenes of individual oil glands in Citrus latipes

Mono- and sesqui-terpenes of individual oil glands of Citrus latipes fruits were analyzed for their homogeneity. The effect of oleocellosis, desiccation, Penicillium and Phytophthora infection upon the individual terpene components was investigated and expressed in a discriminant analysis and in canonical variables. Each oil gland contained the entire spectrum of terpenes specific for each species, and the biggest difference in affected glands was due to Penicillium infection.     

Essential oil variation of Tagetes minuta in South Africa – A chemometric approach

Tagetes minuta L., generally known as wild marigold and locally as “Kakiebos”, has been used traditionally for medicinal purposes in many countries around the world. South Africa is currently the major producer of Tagetes essential oil which is used in perfumery, cosmetics and aromatherapy. The organoleptic and therapeutic properties of an essential oil are dependent upon the chemical profile of the oil. Tagetes essential oil from India, Egypt and the United Kingdom has been reported to be highly variable. In this study, possible chemotypic variation of South African Tagetes oil was explored. Eighty-three individual plants were collected from twenty-one different localities in South Africa. Essential oils were obtained by hydrodistillation using a Clevenger-type apparatus and the oil yield obtained ranged between 0.38 and 1.52%. The essential oils were analysed by gas chromatography coupled to mass spectrometry with flame ionisation detector (GC–MS‒FID) and the major compounds accounting for >85% of the total composition were identified as: (Z)-β-ocimene (27.9–56.0%), (E)-ocimenone (7.4–37.2%), (Z)-tagetone (1.4–24.9%), dihydrotagetone (n.d.−23.4%), (Z)-ocimenone (4.5–13.9%), limonene (n.d.−6.5%) and (E)-tagetone (n.d.−3.2%). Untargeted analysis of GC–MS data using MarkerLynx^® and hierarchical clustering analysis (HCA) revealed two major chemotypes. Further analysis of the two chemotypes using orthogonal projections to latent structures-discriminant analysis (OPLS-DA) identified (E)-tagetone, dihydrotagetone and (Z)-tagetone as characteristic marker constituents for chemotype 1, while chemotype 2 was characterised by (Z)-β-ocimene, (E)-ocimenone and (Z)-ocimenone.     

Essential oil of Ayapana triplinervis from Reunion Island: A good natural source of thymohydroquinone dimethyl ether

Three specimens of Ayapana triplinervis (Vahl) R.M. King & H. Rob from Reunion Island (Indian Ocean) collected at two distant locations (North of the island; samples 1 and 2, South of the island; sample 3), in different growth phases (flowering; samples 1 and 3, vegetative; sample 2) were investigated for their leaf essential oil composition. This study reports the chemical character of this species on the island and investigates the relationship between essential oil composition, developmental stage and geographic location. Analysis by GC–FID and GC–MS enabled us to identify and quantify a total of 39 constituents accounting for 97.1–98.0% of the oils. The three essential oil samples, all obtained by hydrodistillation, showed a high percentage of the aromatic compound thymohydroquinone dimethyl ether (89.9–92.8%). All other minor components remained more or less unchanged both qualitatively and quantitatively with respect to the stage of growth. On the contrary, variations were observed with geographic distribution. The geographical variation of the chemical composition of the volatile oil of A. triplinervis from several sites in the world is also briefly discussed.     

Desulfurization of model and diesel oils by resting cells of Gordona sp.

The desulfurization activity of the resting cells of Gordona sp. CYKS1 was strongly depended on harvest time and the highest value when the cells had been harvested in the early growth phase (0.12 mg sulfur g^–1 cell^–1 h^–1). For the model oil, hexadecane containing dibenzothiophene, the specific desulfurization rate decreased as the reaction proceeded. Both the specific and the volumetric desulfurization rates were not significantly affected by the aqueous-to-oil phase ratio. The diesel oils, light gas oil and a middle distillate unit feed were desulfurized at higher rates (ca. 0.34 mg sulfur g^–1 cell^–1 h^–1) than the model oil (0.12 mg sulfur g^–1 cell^–1 h^–1).