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Plant Essential Oils (plant + essential_oil)
Selected AbstractsHistochemical localization of secretion and composition of the essential oil in Melittis melissophyllum L. subsp. melissophyllum from Central ItalyFLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2010Filippo Maggi Abstract The distribution and morphology of the secretory structures in Melittis melissophyllum L. subsp. melissophyllum (Lamiaceae) were studied for the first time by light and scanning electron microscopy. The indumentum of the vegetative and reproductive organs includes non-glandular hairs and peltate (type A) and capitate (types B and C) glandular trichomes. Histochemical techniques enabled specific location of the site of essential oil accumulation in the type A peltate hairs. In order to confirm the occurrence of the 1-octen-3-ol chemotype in central Italy, six populations growing in different places were analysed for the essential oil composition by GC,FID and GC,MS. In all populations, 1-octen-3-ol was detected as the major volatile component, representing 56.3,70.6% of the total oils. To date, these percentages are the highest detected in a plant essential oil. Copyright © 2009 John Wiley & Sons, Ltd. [source] Combination of a urease inhibitor and a plant essential oil to control coliform bacteria, odour production and ammonia loss from cattle wasteJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2007V.H. Varel Abstract Aim:, To evaluate urea hydrolysis, volatile fatty acid (VFA) production (odour) and coliforms in cattle waste slurries after a urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) and a plant oil component (thymol) were added. Methods and Results:, Faeces from cattle fed a diet of 70% corn silage and 30% alfalfa haylage, urine and distilled water in the ratio 50 : 35 : 15 were blended at high speed for 1 min. Triplicate aliquots of 750 ml were amended with NBPT plus or minus thymol and reblended for 1 min, and were poured into 1·6 l wide-mouth jars covered 90% with a lid. After 56 days, thymol (2000 mg kg,1 waste) in combination with NBPT (80 mg kg,1 waste) retained 5·2 g of an initial 9·2 g of urea in cattle waste slurries, compared with less than 1 g of urea retained when NBPT was the only additive (P < 0·05). Another experiment using excreta from cattle fed 76·25% high moisture corn, 19·25% corn silage and a 4·5% supplement, blended at a low speed, gave a similar response with urea hydrolysis; and the two treatments, thymol alone and thymol in combination with NBPT, reduced VFA production (P < 0·01) and eliminated all coliform bacteria by day 1. A third experiment indicated coliforms disappeared in the no addition treatment after 8 days; however, they were viable at 6·6 × 104 CFU g,1 waste beyond 35 days in the NBPT treatment. Conclusions:, Thymol supplements the effect of NBPT by increasing the inhibitory period for hydrolysis of urea in cattle waste slurries and nitrogen retention in the waste. Significance and Impact of the Study:, Thymol and NBPT offer the potential to reduce odour and pathogens in cattle manure, and increase the fertilizer value. [source] Beyond six scents: defining a seventh Thymus vulgaris chemotype new to southern France by ethanol extractionFLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2009Ken Keefover-Ring Abstract The concept of plant chemotype has long been useful to describe secondary chemical phenotypes; however, the idea has practical limitations, especially when applied to ecological questions. This work reports the discovery of a new 1,8-cineole chemotype of Thymus vulgaris from a well-studied area in southern France. Multivariate statistical analysis of ethanol-extracted plant terpenes was used to describe this new chemotype and three others found at the site, and the results are used to discuss the chemotype concept. While the total amount of essential oils among these chemotypes showed no difference, the concentration of the main terpene differed significantly, with the 1,8-cineole and cis -sabinene hydrate chemotypes having the lowest amounts of their respective main components, and the linalool chemotype having the highest. The , -terpinyl acetate chemotype had intermediate levels of its main terpene. A factor analysis revealed four factors which explained almost 89% of the total variation in plant essential oils. Each factor represented a separate chemotype, including a cis -sabinene hydrate, linalool, ,- terpinyl acetate and the new 1,8-cineole chemotype. Although the concept of plant chemotype is still valid, better definitions are important when evaluating the influences of a plant's secondary chemistry on other community members. Copyright © 2009 John Wiley & Sons, Ltd. [source] Fumigant toxicity of Korean medicinal plant essential oils and components from Asiasarum sieboldi root against Sitophilus oryzae L.FLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2008Junheon Kim Abstract Medicinal plant essential oils and components from Asiasarum sieboldi were tested for their insecticidal activities against the rice weevil Sitophilus oryzae, using a fumigation bioassay. Responses varied with plant material and concentration. The LC50 value of A. sieboldi essential oil against rice weevil was 2.37 µg/ml air. Analysis by gas chromatography,mass spectrometry led to the identification of 20 compounds from A. sieboldi essential oil. Among identified compounds, five main compounds were tested for their insecticidal activity against rice weevil and compared to the toxicity of dichlorvos. Responses varied with compound and dose. Eucarvone was the most toxic, followed by safrole, with LC50 values of 3.32 and 11.27 µg/ml, respectively. LC50 values of other compounds were >25 µg/ml. The LC50 value of dichlorvos was 0.0081 µg/ml. Copyright © 2008 John Wiley & Sons, Ltd. [source] Control of Aspergillus section Flavi growth and aflatoxin accumulation by plant essential oilsJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2008R. Bluma Abstract Aims:, The antifungal effect of Pimpinella anisum (anise), Pëumus boldus (boldus), Mentha piperita (peppermint), Origanum vulgare (oregano) and Minthosthachys verticillata (peperina) essential oils against Aspergillus section Flavi (two isolates of Aspergillus parasiticus and two isolates of Aspergillus flavus) was evaluated in maize meal extract agar at 0·982 and 0·955 water activities, at 25°C. Methods and Results:, The percentage of germination, germ-tube elongation rate, growth rate and aflatoxin B1 (AFB1) accumulation at different essential oils concentrations were evaluated. Anise and boldus essential oils were the most inhibitory at 500 mg kg,1 to all growth parameters of the fungus. These essential oils inhibited the percentage of germination, germ-tube elongation rate and fungal growth. AFB1 accumulation was completely inhibited by anise, boldus and oregano essential oils. Peperina and peppermint essential oils inhibited AFB1 production by 85,90% in all concentrations assayed. Conclusions:, Anise and boldus essential oils could be considered as effective fungitoxicans for Aspergillus section flavi. Significance and Impact of the Study:, Our results suggest that these phytochemical compounds could be used alone or in conjunction with other substances to control the presence of aflatoxigenic fungi in stored maize. [source] ANTIMICROBIAL, PHYSICAL AND MECHANICAL PROPERTIES OF CHITOSAN-BASED FILMS INCORPORATED WITH THYME, CLOVE AND CINNAMON ESSENTIAL OILSJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 6 2009M.H. HOSSEINI ABSTRACT Chitosan-based films containing thyme, clove and cinnamon essential oils at 0.5, 1 and 1.5% v/v were prepared to examine their antibacterial, physical and mechanical properties. Scanning electron microscopy was carried out to explain structure,property relationships. Films containing thyme essential oil revealed larger inhibition zones than those containing clove and cinnamon essential oils against gram-positive and gram-negative bacteria tested. Films were more effective against gram-positive bacteria than gram-negative. Incorporating thyme and clove essential oils into chitosan-based films increased moisture content (from 17.80,28.38%), solubility in water (25.97,30.62%), water vapor transmission rate (0.00233,0.00571 g/s/m2) and elongation at break (25.31,42.70%) of films. Cinnamon-enriched films had opposite changes such as increase in tensile strength (from 12.2,21.35 MPa) and decrease in moisture content (17.80,9.36%) and solubility in water (25.9,14.21%) of films. PRACTICAL APPLICATIONS Microbial growth on food surfaces is a major cause of food spoilage. Combining antimicrobial agents such as plant essential oils directly into a food packaging polymer is a form of active packaging. These films possess the potential for improving microbial stability of foods by acting on the food surface upon contact. Because of the effect of direct addition of plant essential oils to food on sensory characteristics of packaged food, incorporation of essential oils into films may have additional applications in food packaging. [source] Environmental interactions with the toxicity of plant essential oils to the poultry red mite Dermanyssus gallinaeMEDICAL AND VETERINARY ENTOMOLOGY, Issue 1 2010D. R. GEORGE The toxicity of a range of plant essential oils to the poultry red mite, Dermanyssus gallinae (De Geer) (Acari: Dermanyssidae), a serious ectoparasitic pest of laying hens throughout Europe and elsewhere, was assessed in the laboratory. Dermanyssus gallinae may cause losses in egg production, anaemia and, in extreme cases, death of hens. With changes in legislation and consumer demand, alternatives to synthetic acaricides are needed to manage this pest. Fifty plant essential oils were selected for their toxicity to arthropods reported in the literature. Twenty-four of these essential oils were found to kill > 75% of adult D. gallinae in contact toxicity tests over a 24-h period at a rate of 0.21 mg/cm2. Subsequent testing at lower rates showed that the essential oils of cade, manuka and thyme were especially toxic to adult D. gallinae. The toxicity of the seven most acaricidal essential oils was found to be stable at different temperatures likely to be encountered in commercial poultry housing (15°C, 22°C and 29°C), although results suggest that humidity and dust might influence the toxicity of some of the oils tested. The toxicity of clove bud essential oil to D. gallinae, for example, was increased at high humidity and dust levels compared with ambient levels. The results suggest that certain essential oils may make effective botanical pesticides for use against D. gallinae, although it is likely that issues relating to the consistency of the toxic effect of some oils will determine which oils will be most effective in practice. [source] Toxicity of plant essential oils to different life stages of the poultry red mite, Dermanyssus gallinae, and non-target invertebratesMEDICAL AND VETERINARY ENTOMOLOGY, Issue 1 2010D. R. GEORGE Seven essential oils with potential as acaricides for use against the poultry red mite, Dermanyssus gallinae (De Geer) (Acari: Dermanyssidae), were selected for study. These products (essential oils of manuka, cade, pennyroyal, thyme, garlic, clove bud and cinnamon bark) were deployed against different life stages of D. gallinae in laboratory tests at the (lethal concentration) LC50 level for adult mites. For all essential oils tested, toxicity to D. gallinae juveniles was as high as toxicity to adults, if not higher. However, at the LC50 level determined for adults, some oils were ineffective in preventing hatching of D. gallinae eggs. The essential oils were also tested under laboratory conditions at their LC90 levels for D. gallinae adults on two model non-target species, the brine shrimp, Artemia salina (L.), and the mealworm beetle, Tenebrio molitor (L.). Results showed that not all essential oils were as toxic to A. salina and T. molitor as they were to D. gallinae, suggesting that it may be possible to select certain oils for development as acaricides against D. gallinae that would have minimal impact on non-target organisms. However, the level of toxicity to A. salina and T. molitor was not consistent across the selected essential oils. [source] Chemical composition of essential oils of two submerged macrophytes, Ceratophyllum demersum L. and Vallisneria spiralis L.FLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2006Xian Qiming Abstract The essential oils from leaves of Ceratophyllum demersum L. and Vallisneria spiralis L. from China were isolated by steam distillation in yields of 0.15% and 0.10%, respectively, and their chemical composition was examined by GC and GC,MS. More than 50 constituents were identified, representing 87% of the total oils. The main components were basically the same in the two plants' essential oils. 2-Methylpropanoic acid 3-hydroxy-2,4,4-trimethylpentyl ester (>15%), 2-methylpropanoic acid 2,2-dimethyl-1-(2-hydroxy-1-methylethyl)propyl ester (>3%), , -ionone-5,6-epoxide (>7%), toluene (>6%), hexanal (>5%) and 1,2-benzenedicarboxylic acid di(2-methylpropyl) ester (>5%) were the major components. Copyright © 2006 John Wiley & Sons, Ltd. [source] | |||||||||||||