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PubMed2000

Development and evaluation of a model predicting the survival of Escherichia coli O157:H7 NCTC 12900 in homemade eggplant salad at various temperatures, pHs, and oregano essential oil concentrations.

Homemade eggplant salad, a traditional Greek appetizer, was inoculated with Escherichia coli O157:H7 NCTC 12900 supplemented with different concentrations of oregano essential oil (0.0, 0.7, 1. 4, and 2.1% [vol/wt]) and stored at different temperatures (0, 5, 10, and 15 degrees C). The product's pH was adjusted to 4.0, 4.5, or 5. 0 with lemon juice. For each combination of the environmental factors, the bacterial counts were modeled, using the Baranyi model, as a function of time to estimate the kinetic parameters of the pathogen. A reduction of more than 1 log unit in E. coli O157:H7 counts was observed in all cases, and the death rate depended on the pH, the storage temperature, and the essential oil concentration. Separate quadratic models were developed with natural logarithms of the shoulder period and death rate as estimated by the growth model, as a function of temperature, pH, and oregano essential oil concentrations. These were further used to predict the population of E. coli O157:H7 NCTC 12900 from other inoculated eggplant salads at random conditions of temperature, pH, and oregano oil concentration. The predicted values were compared with viable-count measurements for validation.

Colony Count, Microbial↗
PubMed2004

Colorimetric method for identifying plant essential oil components that affect biofilm formation and structure.

The specific biofilm formation (SBF) assay, a technique based on crystal violet staining, was developed to locate plant essential oils and their components that affect biofilm formation. SBF analysis determined that cinnamon, cassia, and citronella oils differentially affected growth-normalized biofilm formation by Escherichia coli. Examination of the corresponding essential oil principal components by the SBF assay revealed that cinnamaldehyde decreased biofilm formation compared to biofilms grown in Luria-Bertani broth, eugenol did not result in a change, and citronellol increased the SBF. To evaluate these results, two microscopy-based assays were employed. First, confocal laser scanning microscopy (CLSM) was used to examine E. coli biofilms cultivated in flow cells, which were quantitatively analyzed by COMSTAT, an image analysis program. The overall trend for five parameters that characterize biofilm development corroborated the findings of the SBF assay. Second, the results of an assay measuring growth-normalized adhesion by direct microscopy concurred with the results of the SBF assay and CLSM imaging. Viability staining indicated that there was reduced toxicity of the essential oil components to cells in biofilms compared to the toxicity to planktonic cells but revealed morphological damage to E. coli after cinnamaldehyde exposure. Cinnamaldehyde also inhibited the swimming motility of E. coli. SBF analysis of three Pseudomonas species exposed to cinnamaldehyde, eugenol, or citronellol revealed diverse responses. The SBF assay could be useful as an initial step for finding plant essential oils and their components that affect biofilm formation and structure.

Bacterial Adhesion↗
PubMed1996

Efficacy of a phyto-aromatic gel against auricular manage in rabbits and carnivores.

The efficacy of a phyto-aromatic gel (Canidor) was evaluated, in vitro against Psoroptes cuniculi and in vivo against P cuniculi and Otodects cynotis, in experimentally and naturally infested rabbits and domestic carnivores respectively. At a 1/1 dilution the gel was 100 per cent active in vitro against P cuniculi after less than six hours of contact. In experimentally infested rabbits the gel was administered daily during two periods of five consecutive days, six days apart. A clinical cure was achieved in all the animals, but two harboured a few eggs and mites at the end of the trial. In dogs and cats the active formulation was given for two periods of four consecutive days, seven days apart. Clinical and parasitological examinations 10 and 30 days after initiating the treatment regiment revealed an excellent acaricidal effect.

Animals↗
PubMed2001

Effects of Cymbopogon nardus (L.) W. Watson essential oil on the growth and morphogenesis of Aspergillus niger.

The growth inhibitory effect of Cymbopogon nardus (L.) W. Watson var. nurdus essential oil on Aspergillus niger (Van Tieghem) mycelium was determined on agar medium. The mycelium growth was completely inhibited at 800 mg/L. This concentration was found to be lethal under the test conditions. Essential oil at 400 mg/L caused growth inhibition of 80% after 4 days of incubation, and a delay in conidiation of 4 days compared with the control. Microscopic observations were carried out to determine the ultrastructural modifications of A. niger hyphae after treatment with C. nardus essential oil. The main change observed by transmission electron microscopy concerned the hyphal diameter and the hyphal wall, which appeared markedly thinner. These modifications in cytological structure might be caused by the interference of the essential oil with the enzymes responsible for wall synthesis which disturb normal growth. Moreover, the essential oil caused plasma membrane disruption and mitochondrial structure disorganization. The findings thus indicate the possibility of exploiting Cymbopogon nardus essential oil as an effective inhibitor of biodegrading and storage-contaminating fungi.

Antifungal Agents↗
PubMed2006

Activity of the essential oil from Chenopodium ambrosioides grown in Cuba against Leishmania amazonensis.

BACKGROUND AND METHODS: Current therapy against leishmaniasis is unsatisfactory. Efficacious and safe new drugs are needed. In this study, we show the leishmanicidal effect of an essential oil from Chenopodium ambrosioides against Leishmania amazonensis. RESULTS: The tested product had a potent inhibitory action against promastigote and amastigote forms, with 50% effective dose values of 3.7 and 4.6 microg/ml, respectively. The essential oil showed a moderate toxicity on macrophages from BALB/c mice. An optimal dose of 30 mg/kg/day was effective when administered during 15 days by intraperitoneal route to BALB/c mice infected experimentally. CONCLUSION: These studies revealed a potential source for the discovery of novel drugs to combat the leishmaniasis based on the traditional medicine.

Animals↗
PubMed2006

Comparison of essential oils from three plants for enhancement of antimicrobial activity of nitrofurantoin against enterobacteria.

BACKGROUND: Piperitone from plant essential oils enhancesbactericidal activities of nitrofurantoin and furazolidone against bacteria from the family Enterobacteriaceae. In this study, the essential oils of spearmint (Mentha spicata L.), dill (Anethum graveolens L.) and peppermint (Mentha piperita L.)were screened for augmentation of nitrofurantoin activity and the most active components were determined. METHOD: The effects of essential oils and their components on the bactericidal activity of nitrofurantoin against Enterobacter cloacae were studied using disk-diffusion and agar-dilution methods. The composition of essential oils was studied using gas chromatography-mass spectrometry. RESULTS: M. spicata and A. graveolens oils exhibited the highest effects. Gas chromatography-mass spectrometry analysis showed that the oils of these two plants contained 40.12 and 20.32% carvone, respectively. Pure carvone and piperitone equally increased the bactericidal activity of nitrofurantoin. Other ingredients of essential oils, including camphor, limonene and menthone, were less effective.

Anethum graveolens↗
PubMed1996

Antifungal activity of the essential oil of Melaleuca alternifolia (tea tree oil) against pathogenic fungi in vitro.

The in vitro antifungal activity of tea oil, the essential oil of Melaleuca alternifolia, has been evaluated against 26 strains of various dermatophyte species, 54 yeasts, among them 32 strains of Candida albicans and other Candida sp. as well as 22 different Malassezia furfur strains. Minimum inhibitory concentrations (MIC) of tea tree oil were measured by agar dilution technique. Tea tree oil was found to be able to inhibit growth of all clinical fungal isolates. For the investigated dermatophytes MIC values from 1,112.5 to 4,450.0 micrograms/ml with a geometric mean of 1,431.5 micrograms/ml were demonstrated. Both C. albicans strains and the other strains belonging to the genus Candida and Trichosporon appeared to be slightly less susceptible to tea tree oil in vitro. However, their MIC values, which varied from 2,225.0 to 4,450.0 micrograms/ml (geometric mean 4,080 micrograms/ml), indicated moderate susceptibility to the essential oil of M. alternifolia. The lipophilic yeast M. furfur seemed to be most susceptible to tea tree oil. MIC values between 556.2 and 4,450.0 micrograms/ml (geometric mean 1,261.5 micrograms/ml) were found against the tested M. furfur strains. However, when calculated as percentage tea tree oil of the agar, the above-mentioned concentrations correspond to 0.5-0.44% tea tree oil content. These values are far below the usual relatively high therapeutic concentrations of the agent; approximately 5-10% solution or even the concentrated essential oil are used for external treatment. In comparison with tea tree oil, in vitro susceptibility against miconazole, an established topical antifungal, was tested. As expected, very low MIC values for miconazole were found for dermatophytes (geometric mean 0.2 microgram/ml), yeasts (geometric mean 1.0 microgram/ml), and M. furfur (geometric mean 2.34 micrograms/ml). It is suggested that the in vivo effect of tea tree oil ointment in the therapy of fungal infections of the skin and mucous membranes as well as in the treatment of dandruff, a mild form of seborrheic dermatitis, may be at least partly due to an antifungal activity of tea tree oil.

Antifungal Agents↗
PubMed2001

Buchu (Agathosma betulina and A. crenulata, Rutaceae) essential oils: their pharmacological action on guinea-pig ileum and antimicrobial activity on microorganisms.

The mode of action of essential oils from two buchu species (Agathosma betulina and A. crenulata, Rutaceae) from the Cape region of South Africa has been studied on smooth muscle in-vitro using guinea-pig ileum. At high concentration, the oils had an initial spasmogenic activity followed by spasmolysis. The spasmolytic action was post-synaptic, not atropine-like and did not involve adrenoceptor or guanylyl cyclase activation. In the presence of the phosphodiesterase inhibitor rolipram, the spasmolytic action of A. betulina was significantly increased whilst that due to A. crenulata was also increased but not to a significant level. These results suggested a mode of action for the oils involving cyclic adenosine monophosphate. In addition, A. betulina appeared to block calcium channels but this was not seen with A. crenulata, possibly because the initial spasmogenic activity complicated the study of its spasmolytic action. Neither essential oil (10 microL, undiluted) demonstrated antimicrobial action against Enterococcus hirae and Pseudomonas aeruginosa but very low activity was observed against Escherichia coli, Saccharomyces cerevisiae and Staphylococcus aureus, suggesting little potential for these oils as antimicrobial agents/preservatives.

Animals↗
PubMed2002

[Quality evaluation of essential oils].

Essential oils on the market were analyzed using GC-MS and the main ingredients of each essential oil were quantified. Analysis of the essential oil of Lavandula officinalis (lavender oil) showed that each sample had a different ratio of the contents of main ingredients, such as linalool, linalyl acetate, and camphor. In addition, some commercial lavender oils were analyzed by GC-MS for comparison with the Lavandula flagrans (lavandin oil) and the reference standard. As a result of this analysis, although the components of almost all commercial lavender oils were approximately the same as those of the reference standard, there were a few products that contained more than 0.5% of the amount of camphor in lavandin oil. This suggests that some lavender oil samples are mixed with lavandin oil to lower the price. Commercial essential oils of Melaleuca alternifolia (teatree oil) and Mentha piperita (peppermint oil) were also analyzed by GC-MS. Each of the peppermint oil samples had a different ratio in the content of its main ingredient. With respect to teatree oils, the amount of terpinens in each sample differed. These results led to concern about the efficacy of essential oils. For achieve the expected efficacy of essential oils, correct information on their ingredients should be available and quality control using instrumental analysis should be introduced.

Gas Chromatography-Mass Spectrometry↗
PubMedDate not supplied

[Study of components in crude drugs by head space gas chromatography. I. Components of Asiasari radix].

Determinations of volatile components of essential oil contained in Asiasari Radix were studied by head space gas chromatography. The head space gas, which was generated by heating 0.2 g of crude drug with 1.0 ml of water at 90 degrees C for 45 min, was analyzed directly by gas chromatography or gas chromatography-mass spectrometry. This method was rapid, and did not require tedious procedures and time consuming, and without contamination of the column.

Chromatography, Gas↗
PubMed1996

[Study of components in crude drugs by headspace gas chromatography. II. Components of atractylodes].

Determination of volatile components in essential oils from Atractylodis plants was studied by headspace gas chromatography. The crude drug of 0.20 g with 1.0 ml of water in a capped vial was heated at 130 degrees C for 45 min. Then 0.5 ml of vaporized components were collected by gas tightsillinge, and were applied into the injection port of GC or GC/MS. Consequently we could analyze and confirm the following components; hinesol and beta-eudesmol were found to be contained in Atractylodis Lanceae Rhizoma and atractylon in Atractylodis Rhizoma. beta-Eudesmol was analyzed by headspace gas chromatography, and the obtained calibration curve showed good linearity over the range from 2.5 micrograms to 10.0 mg. The result agreed with those obtained using numerical analyses by the steam distillation method. Atractylodis was found to have a wide variety of components depending on the available sources and on the stored conditions. This method was, therefore, more rapid and simpler determination of essential oils in crude drugs using headspace gas chromatography than those used previously. The method was useful means of the analyses of components in crude drugs such as Atractylodis plants and quality control.

Chromatography, Gas↗
PubMed1995

Does peppermint oil relieve spasm during barium enema?

The effectiveness of topical peppermint oil added to barium sulphate suspension in relieving colonic muscle spasm during double contrast barium enema examination was assessed in a double blind study. 141 patients were randomized either to a control group (71 patients) examined with standard barium suspension or to the treatment group which received peppermint oil mixed with the barium preparation. No residual spasm was evident in a significant proportion of patients in the treated group (60%) compared with the control group (35%) (p < 0.001). The patients' acceptability of the procedure was good and there were no adverse effects on the overall quality of the examination. In conclusion, the addition of peppermint oil to the barium suspension seems to reduce the incidence of colonic spasm during the examination. The technique is simple, safe, cheap and it may lessen the need for intravenous administration of spasmolytic agents.

Adult↗
PubMed2006

Evaluation of characteristic aroma compounds of Citrus natsudaidai Hayata (Natsudaidai) cold-pressed peel oil.

The characteristic aroma compounds of Citrus natsudaidai Hayata essential oil were evaluated by a combination of instrumental and sensory methods. Sixty compounds were identified and quantified, accounting for 94.08% of the total peel oil constituents. Limonene was the most abundant compound (80.68%), followed by gamma-terpinene (5.30%), myrcene (2.25%) and alpha-pinene (1.30%). Nineteen compounds which could not be identified in the original oil were identified in the oxygenated fraction. Myrcene, linalool, alpha-pinene, beta-pinene, limonene, nonanal, gamma-terpinene, germacrene D, and perillyl alcohol were the active aroma components (FD-factor > 3(6)), whereas beta-copaene, cis-sabinene hydrate and 1-octanol were suggested as characteristic aroma compounds, having a Natsudaidai-like aroma in the GC effluent. Three other compounds, heptyl acetate, (E)-limonene oxide and 2,3-butanediol, which each showed a high RFA value (>35) were considered to be important in the reconstruction of the original Natsudaidai oil from pure odor chemicals. The results indicate that 1-octanol was the aroma impact compound of C. natsudaidai Hayata peel oil.

1-Octanol↗
PubMedDate not supplied

Interpopulation congruence in Chinese Primula ovalifolia revealed by chemical and molecular markers using essential oils and ISSRs.

The chemical composition of the essential oils of five natural populations of P. ovalifolia from central and southwest China and their interpopulation variability were first analyzed by using GC-MS. Twenty-two essential oil compounds were obtained, in which eighteen ones were identified and characterized representing 95%-96% of the oil composition. Three main chemotypes, i.e., the methyl-acetyl-hydroquinone-rich, hydroquinone-rich, and acetyl-hydroquinone-rich chemotypes, were then differentiated, corresponding to the three groups obtained from the cluster analysis based on the essential oil composition percentages. Genetic variations among the five populations were also investigated using the Inter-Simple Sequence Repeats (ISSR) markers. Finally, the Mantel test showed that there was a significant correlation between two distance matrices based on the chemical compounds of essential oils and ISSR markers, confirming the congruence of interpopulation relationships in the P. ovalifolia revealed by the chemical and molecular markers

China↗
PubMedDate not supplied

Insecticidal activity of the essential oil of Ligusticum mutellina roots.

The essential oil obtained from roots of different collections of Ligusticum mutellina was tested against 3rd instar armyworms, Pseudaletia unipuncta (Lepidoptera: Noctuidae), for insecticidal activity. The main compounds were isolated and their structures were elucidated using 2D-NMR techniques. Our collections contained dillapiole, ligustilide and myristicin as major compounds. The previously reported sarisan was not present, moreover its occurrence in L. mutellina should be revised based on our findings.

Allylbenzene Derivatives↗
PubMedDate not supplied

Emission of herbivore-induced volatiles in absence of a herbivore--response of Zea mays to green leaf volatiles and terpenoids.

Green leaf volatiles (GLV), a series of saturated and monounsaturated six-carbon aldehydes, alcohols, and esters are emitted by plants upon mechanical damage. Evidence is increasing that intact plants respond to GLV by activating their own defense mechanisms, thus suggesting that they function in plant-plant communication. The present paper demonstrates that exposure of maize plants to naturally occurring GLV, including (Z)-3-, (E)-2- and saturated derivatives, induce the emission of volatile blends typically associated with herbivory. Position or configuration of a double bond, but not the functional group of the GLV influenced the strength of the emissions. (Z)-3-Configured compounds elicited stronger responses than (E)-2- and saturated derivatives. The response to (Z)-3-hexen-1-ol increased linearly with the dose between 200 and 1000 nmol per plant. Not only the naturally occurring (E)-2-hexenal, but also (E)-2-pentenal and (E)-2-heptenal induced maize plants, although to a lesser extent. Externally applied terpenoids [(3E)-4,8-dimethyl-1,3,7-nonatriene, beta-caryophyllene, and (E)-beta-farnesene] did not significantly increase the total amount of inducible volatiles in maize. Of three tested maize cultivars Delprim and Pactol responded much stronger than Attribut. Recovery experiments in the presence and absence of maize plants demonstrated that large proportions of externally applied GLV were assimilated by the plants, whereas (3E)-4,8-dimethyl-1,3,7-nonatriene was recovered in much higher amounts. The results furthermore suggested that plants converted a part of the assimilated leaf aldehydes and alcohols to the respective acetates. We propose that GLV not only can alert neighboring plants, but may facilitate intra-plant information transfer and can help mediate the systemic defense response in a plant.

Animals↗
PubMed2004

[Antibacterial activity of essential oils on microorganisms isolated from urinary tract infection].

The antibacterial activity of essential oils extracted from medicinal plants (Ocimum gratissimum, L., Cybopogum citratus (DC) Stapf., and Salvia officinalis, L.) was assessed on bacterial strains derived from 100 urine samples. Samples were taken from subjects diagnosed with urinary tract infection living in the community. Microorganisms were plated on Müller Hinton agar. Plant extracts were applied using a Steers replicator and petri dishes were incubated at 37 degrees C for 24 hours. Salvia officinalis, L. showed enhanced inhibitory activity compared to the other two herbs, with 100% efficiency against Klebsiella and Enterobacter species, 96% against Escherichia coli, 83% against Proteus mirabilis, and 75% against Morganella morganii.

Animals↗
PubMedDate not supplied

Antibacterial activity of Ocimum gratissimum L. essential oil.

The essential oil (EO) of Ocimum gratissimum inhibited Staphylococcus aureus at a concentration of 0.75 mg/ml. The minimal inhibitory concentrations (MICs) for Shigella flexineri, Salmonella enteritidis, Escherichia coli, Klebsiella sp., and Proteus mirabilis were at concentrations ranging from 3 to 12 microg/ml. The endpoint was not reached for Pseudomonas aeruginosa (>=24 mg/ml). The MICs of the reference drugs used in this study were similar to those presented in other reports. The minimum bactericidal concentration of EO was within a twofold dilution of the MIC for this organism. The compound that showed antibacterial activity in the EO of O. gratissimum was identified as eugenol and structural findings were further supported by gas chromatography/mass spectra retention time data. The structure was supported by spectroscopic methods.

Enterobacteriaceae↗