Larvicidal activity of essential oils extracted from commonly used herbs in Lebanon against the seaside mosquito, Ochlerotatus caspius

This study investigates the potential of essential oils from commonly used medical and culinary herbs in Lebanon as an environmentally safe measure to control the seaside mosquito, Ochlerotatus caspius. The composition of essential oils extracted from parsley seeds and leaves, alpine thyme inflorescences, anis seeds, and coriander fruits were analyzed by GC-MS, and the major components of these oils were found to be thymol, sabinene, carvacrol, anethole, and linalool, respectively. Mosquito larvicidal assays were conducted to evaluate the LC(50) and LC(90) after 24 and 48h of the essential oils and their major constituents. All of the tested oils proved to have strong larvicidal activity (LC(50): 15-156ppm) against Oc. caspius fourth instars, with the most potent oil being thyme inflorescence extract, followed by parsley seed oil, aniseed oil, and then coriander fruit oil. Toxicity of each oil major constituent was also estimated and compared to a reported larvicidal compound, eugenol.     

In vitro evaluation of the effects of some plant essential oils on Ascosphaera apis,the causative agent of Chalkbrood disease

Ascosphaera apis is one of the major fungal pathogens of honey bee broods and the causative agent of Chalkbrood disease. The factors responsible for the pathogenesis of Chalkbrood disease are still not fully understood, and the increasing resistance of A. apis to commonly used antifungal agents necessitates a search for new agents to control this disease. The in vitro antifungal activities of 27 plant essential oils against two isolates of A. apis (Aksu-4 and Aksu-9) were evaluated. Out of the 27 plant essential oils tested, 21 were found to be effective in killing both isolates of A. apis. Based on their minimum fungicidal concentration (MFC) values, the effective oils were grouped into three categories: highly effective, moderately effective and minimally effective. Mountain pepper oil, Kala Bhangra oil, spearmint oil, babuna oil, betel leaf oil, carrot seed oil, cumin seed oil and clove bud oil were highly effective, with MBC values between 50.0 μg/mL and 600.0 μg/mL. Mountain pepper was the most effective essential oil, with an MBC value of 50.0 μg/mL. Citral and caryophyllene containing oils were the most effective with MIC 50 ppm. The essential oils tested exhibited significant antimicrobial activities against both strains of A. apis, and they may contain compounds that could play an important role in the treatment or prevention of Chalkbrood disease of honeybee.     

Distillation Time as Tool for Improved Antimalarial Activity and Differential Oil Composition of Cumin Seed Oil

A steam distillation extraction kinetics experiment was conducted to estimate essential oil yield, composition, antimalarial, and antioxidant capacity of cumin (Cuminum cyminum L.) seed (fruits). Furthermore, regression models were developed to predict essential oil yield and composition for a given duration of the steam distillation time (DT). Ten DT durations were tested in this study: 5, 7.5, 15, 30, 60, 120, 240, 360, 480, and 600 min. Oil yields increased with an increase in the DT. Maximum oil yield (content, 2.3 g/100 seed), was achieved at 480 min; longer DT did not increase oil yields. The concentrations of the major oil constituents α-pinene (0.14–0.5% concentration range), β-pinene (3.7–10.3% range), γ-cymene (5–7.3% range), γ-terpinene (1.8–7.2% range), cumin aldehyde (50–66% range), α-terpinen-7-al (3.8–16% range), and β-terpinen-7-al (12–20% range) varied as a function of the DT. The concentrations of α-pinene, β-pinene, γ-cymene, γ-terpinene in the oil increased with the increase of the duration of the DT; α-pinene was highest in the oil obtained at 600 min DT, β-pinene and γ-terpinene reached maximum concentrations in the oil at 360 min DT; γ-cymene reached a maximum in the oil at 60 min DT, cumin aldehyde was high in the oils obtained at 5–60 min DT, and low in the oils obtained at 240–600 min DT, α-terpinen-7-al reached maximum in the oils obtained at 480 or 600 min DT, whereas β-terpinen-7-al reached a maximum concentration in the oil at 60 min DT. The yield of individual oil constituents (calculated from the oil yields and the concentration of a given compound at a particular DT) increased and reached a maximum at 480 or 600 min DT. The antimalarial activity of the cumin seed oil obtained during the 0–5 and at 5–7.5 min DT timeframes was twice higher than the antimalarial activity of the oils obtained at the other DT. This study opens the possibility for distinct marketing and utilization for these improved oils. The antioxidant capacity of the oil was highest in the oil obtained at 30 min DT and lowest in the oil from 360 min DT. The Michaelis-Menton and the Power nonlinear regression models developed in this study can be utilized to predict essential oil yield and composition of cumin seed at any given duration of DT and may also be useful to compare previous reports on cumin oil yield and composition. DT can be utilized to obtain cumin seed oil with improved antimalarial activity, improved antioxidant capacity, and with various compositions.     

Antioxidant properties of essential oils: autoxidation of essential oils from laurel and fennel and effects of mixing with essential oil from coriander

Changes in the composition of essential oils from the seeds of laurel (Laurus nobilis L.) and fennel (Foeniculum vulgare Mill., var. dulce Thelling) and their mixture with essential oil from coriander were studied by capillary gas-liquid chromatography during storage in the dark and in light. Under these conditions, essential oil of laurel retained its composition for 12 months. Essential oil of fennel was rapidly oxidized in light. However, the rate of its oxidation in the dark was lower. The major component of essential oil of fennel, transanethol, had a lower antioxidant activity than essential oil of coriander. The mixture of essential oils from laurel and coriander possessed antioxidant properties and strongly inhibited the oxidation of components of the fennel oil.     

Bactericidal activity of some plant essential oils against Ralstonia solanacearum infection

Potato plants and their tubers in Egypt are affected by one of the most renowned soil-borne pathogen, Ralstonia solanacearum, that caused brown rot in potato tubers and wilt in plants. There is no efficient therapeutic bactericide so; control of bacterial wilt is very rough.The study investigated three different concentrations of seven essential plant oils under in vitro and in vivo conditions as a result of their effects on Ralstonia solanacearum growth and their possibility use as potato seed pieces dressing for controlling bacterial wilt disease incidence. In vitro, anise oil at the three tested different concentrations (0.04, 0.07, and 0.14% vol/vol) was the most effective one inhibiting the growth of T4 and W9 isolates of Ralstonia solanacearum then pursued by thyme, lemongrass, and clove oils. On the other hand, rocket oil at the tested concentration was the least effective one followed by fennel oil. However, wheat germ oil was not completely effective. In vivo, experiment revealed that anise oil at the three concentrations significantly reduced disease incidence and severity in sponta and hermes potato cultivars and their effect was associated with increase of peroxidase, polyphenoloxidase, phenols and the foliar fresh weight of treated plants as well as the weight of tubers/plant followed by thyme and lemongrass oils compared to the infected untreated control.Morphological differences in bacterial cell structure have been observed using a transmission electron microscope (TEM). Anise oil at higher concentration caused of cell wall rupture and degraded cellular components.     

Production of environmentally safe biocides from essential oils having antimicrobial activity

Different liquid formulations of anise, coriander and black cumin essential oils were used for preparing some biocides. The prepared formulations were tested for their antimicrobial activity against some post-harvest pathogenic microorganisms. The tested microorganisms were Fusarium oxysporum (Dray rot of potato), Alternaria alternata (Black rot of tomato), Penicillium italicum, P. digitatum, (Blue and green rot of orange, respectively), Botryitus cinerea (Gray rot of strawberry) and Erwinia carotovora (Soft rot of potato).The results revealed that the different formulations showed a complete inhibition effect on the growth of most of the tested microorganisms. Also, the antimicrobial activity of the formulated essential oils did not affect the formulation process compared with the original oil.     

Purification of a jojoba embryo fatty acyl-coenzyme A reductase and expression of its cDNA in high erucic acid rapeseed

The jojoba (Simmondsia chinensis) plant produces esters of long-chain alcohols and fatty acids (waxes) as a seed lipid energy reserve. This is in contrast to the triglycerides found in seeds of other plants. We purified an alcohol-forming fatty acyl-coenzyme A reductase (FAR) from developing embryos and cloned the cDNA encoding the enzyme. Expression of a cDNA in Escherichia coli confers FAR activity upon those cells and results in the accumulation of fatty alcohols. The FAR sequence shows significant homology to an Arabidopsis protein of unknown function that is essential for pollen development. When the jojoba FAR cDNA is expressed in embryos of Brassica napus, long-chain alcohols can be detected in transmethylated seed oils. Resynthesis of the gene to reduce its A plus T content resulted in increased levels of alcohol production. In addition to free alcohols, novel wax esters were detected in the transgenic seed oils. In vitro assays revealed that B. napus embryos have an endogenous fatty acyl-coenzyme A: fatty alcohol acyl-transferase activity that could account for this wax synthesis. Thus, introduction of a single cDNA into B. napus results in a redirection of a portion of seed oil synthesis from triglycerides to waxes.     

Antioxidant Properties of Essential Oils: Autoxidation of Essential Oils from Laurel and Fennel and of Their Mixtures with Essential Oil from Coriander

Changes in the composition of essential oils from the seeds of laurel (Laurus nobilis L.) and fennel (Foeniculum vulgare Mill., var. dulce Thelling) and their mixture with essential oil from coriander were studied by capillary gas-liquid chromatography during storage in the dark and in light. Under these conditions, essential oil of laurel retained its composition for 12 months. Essential oil of fennel was rapidly oxidized in light. However, the rate of its oxidation in the dark was lower. The major component of essential oil of fennel, trans-anethol, had a lower antioxidant activity than essential oil of coriander. The mixture of essential oils from laurel and coriander possessed antioxidant properties and strongly inhibited the oxidation of components of the fennel oil.     

Antioxidant properties of essential oils from lemon, grapefruit, coriander, clove, and their mixtures

Antioxidant properties of individual essential oils from lemon (Citrus limon L.), pink grapefruit (Citrus paradise L.), coriander (Coriandrum sativum L.), and clove (Caryophyllus aromaticus L.) buds and their mixtures were studied by capillary gas-liquid chromatography. Antioxidant activity was assessed by oxidation of the aliphatic aldehyde hexanal to the carboxylic acid. The lowest and highest antioxidant activities were exhibited by grapefruit and clove bud essential oils, respectively. Mixtures containing clove bud essential oil also strongly inhibited oxidation of hexanal. Changes in the composition of essential oils and their mixtures in the course of long-term storage in the light were studied. The stability of components of lemon and coriander essential oils in mixtures increased compared to individual essential oils.     

A jojoba beta-Ketoacyl-CoA synthase cDNA complements the canola fatty acid elongation mutation in transgenic plants.

beta-Ketoacyl-coenzyme A (CoA) synthase (KCS) catalyzes the condensation of malonyl-CoA with long-chain acyl-CoA. This reaction is the initial step of the microsomal fatty acyl-CoA elongation pathway responsible for formation of very long chain fatty acids (VLCFAs, or fatty acids with chain lengths > 18 carbons). Manipulation of this pathway is significant for agriculture, because it is the basis of conversion of high erucic acid rapeseed into canola. High erucic acid rapeseed oil, used as an industrial feedstock, is rich in VLCFAs, whereas the edible oil extracted from canola is essentially devoid of VLCFAs. Here, we report the cloning of a cDNA from developing jojoba embryos involved in microsomal fatty acid elongation. The jojoba cDNA is homologous to the recently cloned Arabidopsis FATTY ACID ELONGATION1 (FAE1) gene that has been suggested to encode KCS. We characterize the jojoba enzyme and present biochemical data indicating that the jojoba cDNA does indeed encode KCS. Transformation of low erucic acid rapeseed with the jojoba cDNA restored KCS activity to developing embryos and altered the transgenic seed oil composition to contain high levels of VLCFAs. The data reveal the key role KCS plays in determining the chain lengths of fatty acids found in seed oils.     

Toxicity of plant essential oils and their components against Lycoriella ingenua (Diptera: Sciaridae)

Plant essential oils from 20 plant species were tested for their insecticidal activity against larvae of Lycoriella ingenua (Dufour) (Diptera: Sciaridae) by using a fumigation bioassay. Good insecticidal activity (>90%) against larvae of L. ingenua was achieved with essential oils of caraway seed Carum carvi (L.)], lemongrass [Cymbopogon citratus (D.C.) Stapf.], mandarine (Citrus reticulate Blanco), nutmeg (Myristica fragrans Houtt), cade (Juniperus oxycedrus L.), spearmint (Mentha spicata L.), cumin (Cuminum cyminum L.), and thyme red [Thymus vulgaris (L.)] oils at 30 X 10-3 mg/1 air. Among them, caraway seed, spearmint, cumin, and thyme red essential oils were highly effective against L. ingenua at 20 x 10(-3) mg/ml air. Analysis by gas chromatography-mass spectrometry led to identification of 4, 9, 8, and 17 compounds from caraway seed, spearmint, cumin, and thyme red oils, respectively. These compounds were tested individually for their insecticidal activities against larvae of L. ingenua, and compared with the toxicity of dichlorvos. Carvacrol, thymol, linalool, cuminaldehyde, p-cymen, terpinen-4-ol, and carvone was effective at 10 x 10(-3) mg/l. The insecticidal activity of dichlorvos was 60% at 10 x 10(-3) mg/ml. Effects of four selected plant essential oils on growth of oyster mushroom, Pleurotus ostreatus, also were investigated.     

Influence of magnetopriming on germination,growth, physiology,oil and essential contents of cumin (Cuminum cyminum L.)

An environment friendly technique is desirable for enhancing of crop production. In this study, seeds of cumin (Cuminum cyminum L.) Yazd accession were treated with 0, 150 mT, 250 mT, 500 mT and 1 T magnetic field strengths for min and germination parameters were determined. All of the treatments improved germination parameters and seedling growth as compared with the control. However, 500 and 150 mT were the most effective treatments and thus selected for field studies. Seeds were exposed to 150 mT and 500 mT static magnetic field of strengths for 12 min, planted in the field during 2010–2012 in Isfahan, Iran. Static magnetic field treatment shortened the days to emergence, flowering and maturity, increased chlorophyll and reduced proline contents. Highest biological, seed and essential oil yield, oil content, and oil yield were recorded under 500 mT followed by 150 mT and control, respectively. The results suggested that the pretreatment of cumin seeds with static magnetic field can improve germination, growth and oil and essential contents of the cumin seed under the field.     

Comparison of solid‐phase cytometry and the plate count method for the evaluation of the survival of bacteria in pharmaceutical oils

Aim: To compare the survival of four bacterial strains (Escherichia coli, Proteus mirabilis, Staphylococcus aureus, Pseudomonas aeruginosa) in pharmaceutical oils, including jojoba oil/tea tree oil, carbol oil, jojoba oil and sesame oil. Methods and Results: Oils were spiked with the test bacteria in a concentration of 10⁴ CFU ml^?1. Bacteria were extracted from oils with phosphate‐buffered saline containing 0·5% Tween 20. Aliquots of the pooled water layers were analysed by solid‐phase cytometry and plate counting. Plate counts dropped to zero for all test strains exposed for 24 h to three of the four oils. In contrast, significant numbers of viable cells were still detected by SPC, except in the jojoba oil/tea tree oil mixture and partly in sesame oil. Conclusions: Exposure of bacteria for 24 h to the two oils containing an antimicrobial led to a loss of their culturability but not necessarily of their viability. The antibacterial activity of the jojoba oil/tea tree oil mixture supersedes that of carbol oil. Significance and Impact of the Study: These in vitro data suggest that the jojoba oil/tea tree oil mixture more than carbol oil inhibits bacterial proliferation when used for intermittent self‐catherization.     

Effects of Sunflower Oil on Tomato Powdery Mildew Caused by Oidium neolycopersici

When tomato leaves were sprayed with 0.1% emulsified canola oil, corn oil, grape seed oil, peanut oil, safflower oil, soya bean oil or sunflower oil, the severity of powdery mildew caused by Oidium neolycopersici was greatly reduced. Among these edible oils tested, sunflower oil was the most effective in the control of powdery mildew. When sprayed with 0.5% sunflower oil, powdery mildew on tomato leaves was reduced to a negligible level. Sunflower oil applied to halves of upper leaf surface did not induce resistance against the pathogen in the non‐treated halves. When applied to halves of lower leaf surface, it also failed to reduce the severity of powdery mildew on the upper leaf surface right above the treated area indicating that control of the powdery mildew by sunflower oil did not result from activation of host defence mechanisms. Scanning electron microscopy showed that control of powdery mildew with sunflower oil resulted mainly from the inhibition of conidial germination and suppression of mycelial growth of the pathogen.     

芫荽子超临界CO2流体萃取和水汽蒸馏精油的化学成分研究

本文采用GC和GC-MS技术对芫荽子超临界CO_2流体萃取(SFE-CO_2)精油的化学成分进行了剖析,并与水汽蒸馏(SD)精油作了比较。结果表明,两种产物的主要组分均为芳樟醇,分别占91.08％(SD)和65.79％(SFE-CO_2)。共有67种化合物被鉴定,其中21种为首次在芫荽子精油中被发现。     

Antioxidant properties of essential oils from lemon,grapefruit, coriander,clove, and their mixtures

Antioxidant properties of individual essential oils from lemon (Citrus limon L.), pink grapefruit (Citrus paradisi L.), coriander (Coriandrum sativum L.), and clove (Caryophyllus aromaticus L.) buds and their mixtures were studied by capillary gas-liquid chromatography. Antioxidant activity was assessed by oxidation of the aliphatic aldehyde hexanal to the carboxylic acid. The lowest and highest antioxidant activities were exhibited by grapefruit and clove bud essential oils, respectively. Mixtures containing clove bud essential oil also strongly inhibited oxidation of hexanal. Changes in the composition of essential oils and their mixtures in the course of long-term storage in the light were studied. The stability of components of lemon and coriander essential oils in mixtures increased compared to individual essential oils.     

Effect of orange essential oil and its constitutes on late blight disease of potato plants under field conditions

Late blight caused by Phytophthora infestans is the most important disease attacking potato plants. Four concentrations of essential oils i.e. 0.0, 1.25, 2.5, 5.0 and 7.5 ml/l of Orange, Citral, Methyl antranate (MA), and Terbinol were tested for controlling late blight disease. Results indicate that all treatments except orange oil have an inhibitory effect against the linear growth of P. infestans. Complete reduction in linear growth was obtained with Citral and MA at concentrations of 5.0 and 7.5 ml/l. Other treatments showed moderate effect against P. infestans. In greenhouse experiments, results indicate that all treatments have protective and therapeutic effects against late blight disease except Orange oil which has a protective effect only. High reduction was obtained with Citral and MA at concentrations of 2.5 and 5.0 ml/l which reduced the disease severity by more than 77.1 and 62.8% when applied as protective and therapeutic treatments respectively. Moderate effect was obtained with orange oil and Citral at concentration of 7.5 ml/l for both treatments which reduced the disease severity by more than 65.7% when applied as protective treatments. Similar results were obtained under field coditions; results indicate that all treatments reduced the late blight severity during two growing seasons. High reduction was obtained with Citral and MA at concentrations of 2.5 and 5.0 ml/l which reduced the disease severity by more than 80.0%. As for potato yield, results indicate that all treatments increased potato yield during two growing seasons. A high increase was obtained with Citral and MA at concentrations of 2.5 and 5.0 ml/l which increased the potato yield by more than 59.1%. Other treatments showed a moderate increase. It could be suggested that some essential oils of citrus or their constituents might be used for controlling late blight disease potato plants under field conditions.     

Trichloroethylene cometabolic degradation by Rhodococcus sp. L4 induced with plant essential oils

Cometabolic degradation of TCE by toluene-degrading bacteria has the potential for being a cost-effective bioremediation technology. However, the application of toluene may pose environmental problems. In this study, several plant essential oils and their components were examined as alternative inducer for TCE cometabolic degradation in a toluene-degrading bacterium, Rhodococcus sp. L4. Using the initial TCE concentration of 80 muM, lemon and lemongrass oil-grown cells were capable of 20 +/- 6% and 27 +/- 8% TCE degradation, which were lower than that of toluene-grown cells (57 +/- 5%). The ability of TCE degradation increased to 36 +/- 6% when the bacterium was induced with cumin oil. The induction of TCE-degrading enzymes was suggested to be due to the presence of citral, cumin aldehyde, cumene, and limonene in these essential oils. In particular, the efficiency of cumin aldehyde and cumene as inducers for TCE cometabolic degradation was similar to toluene. TCE transformation capacities (T (c)) for these induced cells were between 9.4 and 15.1 mug of TCE mg cells(-1), which were similar to the known toluene, phenol, propane or ammonia degraders. Since these plant essential oils are abundant and considered non-toxic to humans, they may be applied to stimulate TCE degradation in the environment.     

The essential oil of pectis papposa

This oil, produced by a heavily scented herbaceous plant of the American Southwest and northern Mexico, is rich in cumaldehyde and carvone, and is therefore a potential commercial source of these fragrant aldehydes, now obtained from cumin, caraway and dill seed oils and used in Savoring food and beverages.     

Dietary flax seed oil and/or Vitamin E improve sperm parameters of cloned goats following freezing-thawing

Semen cryopreservation is affected by individual differences and use of clones animal from the same source is the main tool to eliminate genetic variation. Among many nutrients that are necessary for fertility, essential fatty acids and antioxidants are vital for production of healthy sperm by improving sperm membrane integrity and protecting sperm from oxidative stress. The goal of the current study was to investigate whether a flax seed oil or/and Vitamin E dietary supplementation could improve semen quality of cloned bucks following semen cryopreservation. Accordingly, eight adult cloned Bakhtiari bucks were divided randomly into four groups. Bucks were offered a base diet of hay and concentrate. The concentrate was enriched with flax seed oil, 30 gr/kg body weight/day (OIL), Vitamin E (VIT), 3 gr/kg body weight/day, or combined flax seed oil and the vitamin E (OIL-VIT). The concentrate with no supplements was considered as control group (CONT). Both flax seed oil and Vitamin E supplements were added to the total diet. The bucks were fed with their corresponding diets for a total of 9 weeks while sperm collection was carried out within 10–14 weeks. Ejaculates were diluted with Andromed^® and were frozen in liquid nitrogen. Sperm parameters and reactive oxygen species (ROS) contents were evaluated following freezing/thawing. According to the results of our study, dietary supplementation with flax seed oil, or/and Vitamin E can improve sperm motility, vitality and number of sperm with intact plasma membrane following freezing-thawing. But the degree of improvement in these parameters was significantly higher when Flax seed oil and vitamin E were co-supplemented.