4,881 research outputs found

    Gas Chromaotography-Mass Spectrometry Analysis of Insecticidal Essential Oil Derived from Chinese Ainsliaea fragrans Champ ex Benth (Compositae)

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    Purpose: To investigate the chemical composition and insecticidal activity of the essential oil of the aerial parts of Ainsliaea fragrans against maize weevils (Sitophilus zeamais).Methods: The essential oil of A. fragrans aerial parts was obtained by hydrodistillation and analyzed by gas chromatography (GC) and gas chromaotography-mass spectrometry (GC-MS). Contact toxicity of the essential oil and its major constituents was determined by topical application against S. zeamais.Results: A total of 30 components of the essential oil were identified. The major constituents were myristicin (41.3 %), elemicine (11.9 %), cis-isosafrole (11.5 %), borneol (9.1 %) and caryophyllene (8.8 %). The essential oil of A. fragrans exhibited contact toxicity against S. zeamais with LC50 value of 50.7 μg/adult. Elemicine possessed the strongest contact toxicity (LC50 = 13.5 μg/adult) while cis-isosafrole, myristicin, caryophyllene and borneol had LC50 values of 31.2 μg/adult, 43.4 μg/adult, 57.9 μg/adult, and 98.4 μg/adult, respectively.Conclusion: The study indicates that the essential oil of A. fragrans aerial parts and its major constituents have a potential for development into natural insecticides for the control of grain storage insects.Keywords: Ainsliaea fragrans, Sitophilus zeamais, Contact toxicity, Elemicine, Essential oil, Grain storag

    Chemical Composition of Salvia plebeian R.Br. Essential Oil and its Larvicidal Activity against Aedes aegypti L

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    Purpose: To evaluate the larvicidal activity of the essential oil of Salvia plebeian R.Br. (Labiatae) aerial parts against the larvae of Aedes aegypti L.Methods: The essential oil of S. plebeian aerial parts was obtained by hydro-distillation and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The essential oil was evaluated for larvicidal activity using World Health Organization (WHO) procedures, against the fourth larvae of A. aegypti within 24 h, and activity was recorded for various concentrations of the ranging from 12.5 – 200.0 μg/mL.Results: A total of 33 components of the essential oil of S. plebeian were identified. The major compounds of the essential oil were caryophyllene oxide (15.54 %), γ-eudesmol (14.03 %), τ-cadinol (10.21 %), calamenene (9.63 %), copaene (5.70 %), γ-cadinene (5.30 %), cadalene (5.28 %), α- muurolene (5.19 %), ledol (5.14 %) and α-cadinol (5.08 %). The essential oil exhibited larvicidal activity against A. aegypti at a median lethal concentration (LC50) of 46.26 μg/mL.Conclusion: The findings indicate that the essential oil of S. plebeian aerial parts has potentials for use in the control of A. aegypti larvae and may be useful in the search for newer, safer and more effective natural compounds as larvicides.Keywords: Salvia plebeian, Essential oil, Larvicidal activity, Aedes aegypti, Caryophyllene oxide, γ- Eudesmol, τ-Cadinol, Calamenen

    Larvicidal activity of Illicium difengpi BN Chang (Schisandraceae) Stem Bark and its Constituent Compounds against Aedes aegypti L

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    Purpose: To determine the larvicidal activity of the essential oil derived from Illicium difengpi B.N. Chang stem bark (Schisandraceae) and its major constituents against the larvae of Aedes aegypti L.Methods: Essential oil of I. difengpi stem bark was obtained by hydrodistillation and analyzed by gas chromatography (GC) and gas chromaotography-mas spectrometry (GC-MS). The activity of the essential oil and its major constituents was evaluated, using World Health Organization (WHO) procedures, against the fourth instar larvae of A. aegypti for 24 h, and larval mortalities recorded at essential oil/compound concentrations ranging from 6.0 - 200 μg/mL.Results: A total of 36 components of the essential oil of I. difengpi were identified. The principal compounds are safrole (18.21 %), linalool (13.47 %), 1,8-cineole (12.84 %), and myristicin (8.06 %) followed by α-terpineol (4.77 %), β-pinene (4.45 %) and 4-terpineol (4.38 %). The essential oil exhibited larvicidal activity against A. aegypti with LC50 (median lethal concentration) of 31.68 μg/mL. The major constituents, myristicin, safrole, and 1, 8-cineole, exhibited LC50 of 15.26, 39.45, and 72.18 μg/mL, respectively.Conclusion: The findings obtained indicate that the essential oil of I. difengpi and its major constituents have potentials for use in the control of A. aegypti larvae and may therefore be useful in the search for newer, safer and more effective natural compounds as larvicides.Keywords: Illicium difengpi, Aedes aegypti, Larvicidal activity, Myristicin, Safrole, 1,8-Cineole, Linaloo

    Insecticidal activity of essential oil of Cinnamomum cassia and its main constituent, trans-Cinnamaldehyde, against the booklice, Liposcelis bostrychophila

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    Purpose: To investigate the insecticidal activity of the essential oil of Cinnamomum cassis and its main constituent compound, trans-cinnamaldehyde, against the booklice, Liposcelis bostrychophila.Methods: Steam distillation of C. cassis twigs was carried out using a Clavenger apparatus in order to obtain the volatile oils. Gas chromatography/mass spectrometric (GC/MS) analyses (HP-5MS column) of the essential oil were performed and its contact (using impregnated filter paper method) and fumigant toxicity (sealed space) determined. The bioactive constituent compound, trans-cinnamaldehyde was isolated and identified from the oil based on bioactivity-directed fractionation.Results: A total of 35 components, accounting for 97.44 % of the essential oil of C. cassis, were identified. The principal compounds in the essential oil were trans-cinnamaldehyde (49.33 %), acetophenone (6.94 %), trans-cinnamic acid (5.45 %) and cis-cinnamaldehyde (4.44 %) followed by omethoxycinnamaldehyde (3.48 %), coumarin (3.42 %) and (E)-cinnamyl alcohol (3.21 %). The essential oil displayed contact toxicity against adult L. bostrychophila with a median lethal concentration (LC50) of 55.68 μg/cm2 as well as fumigant toxicity (LC50, 1.33 mg/l air). Trans-cinnamaldehyde exhibited strong contact and fumigant toxicity with LC50 and 1.29 mg/l air, respectively.Conclusion: The findings suggest that the essential oil of C. cassis and its constituent compound, trans-cinnamaldehyde, possess potentials for development into natural fumigants/insecticides for the control of booklice.Keywords: Liposcelis bostrychophila, Cinnamomum cassis, Contact toxicity, Fumigant, trans- Cinnamaldehyde, Essential oi

    Chemical composition and toxic activity of essential oil of Caryopteris incana against Sitophilus zeamais

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    During our screening program for new agrochemicals from Chinese medicinal herbs, essential oil of Caryopteris incana aerial parts was found to possess strong insecticidal activities against the maize weevil, Sitophilus zeamais. A total of 37 components of the essential oil were identified by GC and GC/MS. Estragole (24.8%) and linalool (14.0%) are the two main components of the essential oil followed by 1,8-cineol (5.2%) and δ-guaiene (4.1%). The essential oil possesses strong fumigant toxicity against S. zeamais adults with an LC50 value of 10.05 mg/L air. The essential oil of C. incana also showed contact toxicity against S. zeamais adults with an LD50 value of 122.65 μg/adult. The essential oil C. incana may have potential to be developed as a new natural fumigant/insecticide for the control of stored product insects.Key words: Caryopteris incana, Sitophilus zeamais, fumigant, contact toxicity, essential oil composition, estragole, linalool

    Chemical Composition and Insecticidal Activity of Essential Oil of Artemisia frigida Willd (Compositae) against Two Grain Storage Insects

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    Purpose: To investigate the chemical composition and insecticidal activity of the essential oil of the aerial parts of Artemisia frigida against maize weevils (Sitophilus zeamais) and booklice (Liposcelis bostrychophila)DMethods: Steam distillation of A. frigida aerial parts was carried out in a Clavenger apparatus to extract its volatile oil content. Gas  chromatography/mass spectrometric (GC/MS) analyses (HP-5MS column) ofthe essential oil were performed and its contact toxicity was determined using topical application and filter paper impregnation technique while its fumigant toxicity was evaluated using sealed-space method.Results: A total of 32 components of the essential oil were identified. The principal compounds were cis-ρ-menth-2-en-1-ol (20.8%), 1,8-cineole (12.0%), borneol (10.2%), lavandulol (9.3%), camphor (6.9%), and bicyclogermacrene (5.5%). The oil exhibited contact toxicity against adult S. zeamais and L. bostrychophila with LC50 value of 17.97 µg/adult and 254.38 µg/cm2, respectively. The essential oils also possessed fumigant toxicity against S. zeamais and L. bostrychophila with LC50 value of 69.46mg/L and 1.25 mg/L air.Conclusion: The study indicates that the essential oil of A. frigida has a potential to be developed to a natural fumigant/insecticide for the control of grain storage insects.Keywords: Artemisia frigida, Sitophilus zeamais, Liposcelis bostrychophila, Insecticidal activity, Essential oil, Cis-ρ-Menth-2-en-1-ol; 1,8-Cineol

    Gas Chromatography-Mass Spectrometric Analysis of Essential Oil of Aerial Parts of Glycosmis parviflora (Sims) Little (Rutaceae)

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    Purpose: To investigate the chemical composition and toxicity of the essential oil of Glycosmis parviflora (Sims) Little aerial parts against root-knot nematode and two grain storage insects (maize weevil and red flour beetle).Methods: Steam distillation of G. parviflora was carried out using Clavenger apparatus in order to extract its volatile oil. Gas chromatography/mass spectrometric (GC/MS) analysis (HP-5MS column) of the essential oil was performed and the toxicity of the oil determined by contact test.Results: A total of 37 components comprising 98.7 % of the essential oil were identified, of which (Z)- caryophyllene (20.6 %), methyl isoeugenol (11.1 %), (Z)-β-ocimene (8.9 %), α-cubebene (6.4 %), nerolidol (5.4 %), aromandendrene (4.9 %) and γ-pyronene (4.7 %) were found to be the major components. The essential oil possessed strong nematicidal activity against M. incognita with an LC50 value of 92.84 μg/ml. The essential oil of G. parviflora exhibited strong contact toxicity against S. zeamais and T. castaneum adults with LD50 values of 41.7 and 22.6 μg/adult,  respectively.Conclusion: The study indicates that the essential oil of G. parviflora aerial parts has a potential for development into a natural insecticide/nematicide for control of nematodes and grain storage insects.Keywords: Glycosmis parviflora, Essential oil, Meloidogyne incognita, Sitophilus zeamais, Triboliumcastaneum, Contact toxicit

    Design of a Third-party Reverse Logistics Network under a Carbon Tax Scheme

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    © 2016 Eastern Macedonia and Thrace Institute of Technology. Reverse logistics network involves significant inherent uncertainties, which cannot be completely characterized because of a lack of adequate historical data. In this study, a multi-product and multi-period interval programming model was developed on the basis of partial information to design an effective reverse logistics network. In addition, the trade-offbetween economic benefits and the environmental burdens from carbon emissions was analyzed by considering the effect of a carbon tax scheme on the reverse logistics network design. Through an improved and modified interval linear programming method, the optimal interval solution was obtained with LINGO. Finally, numerical simulations were conducted to explore the effectiveness of the model and the effect of the carbon tax scheme. Results show that the optimal solution of the reverse logistics network design is robust. The effect of the carbon tax scheme is trivial when the carbon tax is low and significant when the carbon tax is high. As carbon tax gradually increases, carbon emissions effectively decrease, but sharply declines the total profit sharply declines. The findings indicate that the proposed model can effectively solve the reverse logistics network design with partial information under a carbon tax scheme

    Identification of furfural resistant strains of Saccharomyces cerevisiae and Saccharomyces paradoxus from a collection of environmental and industrial isolates

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    Background Fermentation of bioethanol using lignocellulosic biomass as a raw material provides a sustainable alternative to current biofuel production methods by utilising waste food streams as raw material. Before lignocellulose can be fermented it requires physical, chemical and enzymatic treatment in order to release monosaccharides, a process that causes the chemical transformation of glucose and xylose into the cyclic aldehydes furfural and hydroxyfurfural. These furan compounds are potent inhibitors of Saccharomyces fermentation, and consequently furfural tolerant strains of Saccharomyces are required for lignocellulosic fermentation. Results This study investigated yeast tolerance to furfural and hydroxyfurfural using a collection of 71 environmental and industrial isolates of the baker’s yeast Saccharomyces cerevisiae and its closest relative Saccharomyces paradoxus. The Saccharomyces strains were initially screened for growth on media containing 100 mM glucose and 1.5 mg ml-1 furfural. Five strains were identified that showed a significant tolerance to growth in the presence of furfural and these were then screened for growth and ethanol production in the presence of increasing amounts (0.1-4 mg ml-1) of furfural. Conclusions Of the five furfural tolerant strains S. cerevisiae NCYC 3451 displayed the greatest furfural resistance, and was able to grow in the presence of up to 3.0 mg ml-1 furfural. Furthermore, ethanol production in this strain did not appear to be inhibited by furfural, with the highest ethanol yield observed at 3.0 mg ml-1 furfural. Although furfural resistance was not found to be a trait specific to any one particular lineage or population, three of the strains were isolated from environments where they might be continually exposed to low levels of furfural through the on-going natural degradation of lignocelluloses, and would therefore develop elevated levels of resistance to these furan compounds. Thus these strains represent good candidates for future studies of genetic variation relevant to understanding and manipulating furfural resistance and in the development of tolerant ethanologenic yeast strains for use in bioethanol production from lignocellulose processing

    Decision Support for Temperate Grasslands: Challenges and Pitfalls

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    Key points Successful adoption of decision support tools (DS tools) to address grassland management issues requires careful attention in design to ensure ease-of-use, accuracy in prediction and the flexibility to simulate actual practices. DS tools must handle spatial variability and where possible include facilities for automatic sourcing of essential information for initialisation. Advances in the development of DS tools will depend on resolution of scientific issues in grassland biology including investment in dedicated experiments to determine parameter values for model equations. The use of mechanistic models, the integration of remote sensing technology and cooperation between research groups to develop modular simulation frameworks to share models will enhance the value of DS tools in grassland management
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