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AbstractThe oil obtained by hydrodistillation of the foral bottom of Syzygium aromaticum(L.) Merr. et Perry was analyzed by GC and GC/MS. Eugenol was the main constituent in the oil (86.7%). The biological activity of the oil applied to Varroa destructorand Apis melliferawas evaluated in two laboratory tests. Mite lethality was estimated using a complete exposure method test with the oil at different concentrations, and a systemic administration method of oil at different concentrations diluted in syrup was placed in feeders for bees. The LC50for complete exposure method at 24 h was 0.59 μL/dish. The inferior and superior limits obtained were 0.47 x 10−6μL/dish and 1.22 μL/dish, respectively. LC50estimated at 48 h showed a slight decrease as compared to that recorded at 24 h. Ratio selection (LC50of A. mellifera/LC50of V. destructor) for complete exposure method was 26.46 and 13.35 for 24 h and 48 h, respectively. Regarding the systemic administration method, mites LC50at 24 h was 12,300 ppm. The inferior and superior limits calculated were 9,214 ppm and 15,178 ppm, respectively. LC50estimated at 48 h showed a slight decrease as compared to that recorded at 24 h. Ratio selection for systemic administration method was 3.05 and 2.22 for 24 h and 48 h, respectively. Syzygium aromaticumoil was found to be an attractant for V. destructorat 4.8% (w/w) concentration. The results showed that oil toxicity against V. destructordiffered depending upon its administration. Nevertheless, the ratio selection calculated by this oil is expected to enable its application under field conditions with a good safety margin. This oil could also be used in combination with other oils in integrated pest management strategies in bee colonies.

AbstractThe Heterothalamus alienusoil was investigated in laboratory for control of different pests that affect the colonies of bees, Apis mellifera, against Varroa destructormite, the bacterium that causes the American Foulbrood, Paenibacillus larvaeand the fungus that produces the chalkbrood, Ascosphaera apis.The oil composition was analyzed by GC and GC/MS, the main components of the oil were β-pinene (44.4%) and trans-muurola-4(14),5-diene (9.2%). The concentration to kill 50% of the mites in 24 h (LC50) was 0.59 mg/cage. Inferior and superior limits were the following ones: 0.34 mg/cage and 1.01 mg/cage, LC50 was estimated for 48 h, and 72 h showed a slight increase with respect to the record of the 24 h. Paenibacillus larvaestrains were Gram positive and catalase negative, the oil presented MIC values of 800–900 mg/L and MBC of 1000–1200 mg/L. Disks of impregnated flter paper with H. alienusoil around colonies of A. apisin growth inhibited the micelial growth signifcantly by 51% in the frst experiment (seven days) and by 31% in the second experiment (eight days).

The aim of this work was to develop a method for determining seven quinolones (ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid and flumequine) in chicken muscle by LC coupled to MS. Two ionisation techniques, ESI and atmospheric pressure chemical ionisation (APCI) were compared using standard solutions. LOD and LOQ were determined under the optimised conditions for the two sources. The ESI was found the best for the purpose. The optimised method (LC‐ESI‐MS) was validated for the simultaneous analysis of the quinolones regulated by European Community in spiked chicken tissues, using norfloxacin as internal standard. Recoveries obtained varied in the range 60–109%. This method was compared with LC‐UV method established previously.

AbstractBiological activity was evaluated of the Tagetes minutaessential oil in different in vitrolaboratory experiments on the mite (Varroa destructor), honeybees (Apis mellifera), the bacterium that causes the American Foulbrood (Paenibacillus larvae), and the fungus that produces chalkbrood (Ascosphaera apis).Two methods of complete exposure were used for mite lethality test: by spraying in Burgerjon's tower with 10 mg of active ingredient in solution with distilled water and emulsion, and in unmodified Petri dishes (60 x 20 mm) with oil (different concentrations) diluted in 1 mL of ethanol. Ratio selection was obtained as: LD50 of Apis mellifera/LD50 of V. destructor.Determination of Minimal Inhibitory Concentrations (MIC): to P. larvaewas tested at concentrations of 25, 50, 100, 150, 200, 250, 350, 450, 500, 600, 650, 700, 800 and 1000 ppm. An A. apisstrain was grown on agar MY20 supplemented with variable concentrations (between 0–800 ppm) of T. minutaoil was evaluated. Results obtained in tests of total exposure showed that the concentration was able to kill 50% of mites in 24 h (DL50) and was estimated to be 4.37 mg/cage. The efficacy after spray treatment reached 56%. The ratio selection was 3:11. Against P. larvae, the oil showed MIC values ranging from 700–800 μL/L depending on the tested bacterial strains. Tagetes minutaoil in agar MY20 inhibited mycelial growth of A. apisabove concentrations of 200 ppm (p = 0.0001). Oil concentrations of 700 and 800 ppm achieved maximum growth inhibition of A. apis(67% of growth inhibition on average). Tagetes minutaoil demonstrated in vitroantibacterial, antifungical and miticide activity, although this oil shows a moderate inhibitor effect compared with other essential oils of native plants from Argentina. However, this oil presents a ratio selection that would allow it to be used in field conditions with a good safety margin. It is possible that this oil can be used in combination with others, in integrated pest management strategies in bee colonies.

AbstractChalkbrood is an invasive mycosis produced by Ascosphaera apisaffecting exclusively the larvae growth of Apis melliferaL. There exists no pharmacological treatment and the chemical products used are not able to control the disease generating resistances and residues in the apicultural production. An ecological alternative is the use of essential oils as natural products to control this mycosis. Eight oils were screened against A. apisfor fungicidal activity. The oils of Baccharis coridifoliaand Eupatorium patensdid not possess any activity while the oils of Tessaria absinthioides, Aloysia gratissima, Heterotheca latifolia, Lippia juneliana, L. integrifoliaand L. turbinataexhibited varying levels of fungicidal activity.

AbstractThe essential oil obtained by hydrodistillation from the fruits of Pimpinella anisumL. (green anise) and Foeniculum vulgareMiller (fennel) were analyzed by GC and GC/MS and physicochemical properties. The oils of P. anisumand F. vulgarewere found to be especially rich in (E)-anethole, 96.3% and 92.7%, respectively. The MICs were determined by the tube dilution method against Paenibacillus larvae.The oils showed MICs values were 300 µg/mL and 250 μg/mL for P. anisumand F. vulgare, respectively. Both oils presented great similarity in physiochemical properties values and antimicrobial activity.

AbstractThe acaricidal effects and adult bee toxicity of Heterotheca latifoliaessential oil on Varroa jacobsonimites were evaluated. The oil was prepared as an emulsion and applied on the varroa females and on adult bees by pulverization in Burgerjon's tower.Varroa lethality test was determined by 3%, 4% and 5% concentrations. The active ingredient was sprayed on the mites placed in groups of 10 on filter papers placed on a plastic dish. As controls, distilled water and water with the emulsifier were used. After spraying, mites were placed in an incubator at 33°±1°C and 70% RH. At these concentrations (3%, 4% and 5%) the oil showed a high mite mortality, while in the control group (water and water + emulsifier) the mortality was lower. Significant differences between control groups and tested groups were observed (p<0.05).At the highest concentrations (5%) H. latifoliaoil did not show bee toxicity. Significant differences between control and tested groups were not observed (p>().()5).These results suggested that H. latifoliaoil might play an important role in this honeybee parasitosis management.

AbstractThe essential oil from Hyptis mutabilis(Rich.) Briq., obtained by hydrodistillation of the aerial part of the plants over two consecutive years, and collected at diferent vegetative stages, flowering and flowering-fructification, did not differ in regard to the composition of analyzed sesquiterpenes but showed variation in the relative concentration of one of its constituents. The oil yield decreased from 0.5% during flowering to 0.3% during flowering-fructification (fresh weight basis). It was analyzed by GC and GC/MS. Twenty-four compounds were identified, which represented 93–5% of the oil in the flowering stage and 92.5% of it in the flowering-fructification one. The oil was found to contain β-caryophyllene (14.3–12.0%), germacrene D (14.7–15.3%), curzerene (11.5–12.7%) and bicyclogermacrene (12.1–14.2%) as major compounds.

AbstractThe hydrodistilled oil from the fresh and dried aerial parts of Tessaria absinthioideswas analyzed by a combination of GC and GC/MS. Thirty-three compounds representing 85% of the oil were identified. The main components of the oil were caryophyllene oxide (12.2%), (E)-β-damascenone (8.6%) and γ-eudesmol (8.5%). The oil consisted of about 32% oxygenated monoterpenes, 36% oxygenated sesquiterpenes and 17% sesquiterpene hydrocarbons. The ratio of oxygenated monoterpenes to oxygenated sesquiterpenes changed from 4.8 to 0.9 in oil of air-dried versus oil of fresh material

AbstractOils obtained by hydrodistillation, separately from flowers and leaves of Heterotheca latifoliaBuck. (Compositae), which is a weed in west central Argentina, were analyzed by GC and GC/MS. Twenty-eight compounds were identified in the flower oil representing 88.9%; and 90.7% of the leaf oil was represented by 15 compounds. Although the composition of both oils was similar, the quantity of individual components differed between them. The major components of both oils were borneol (19.0-39.9%) and camphor (12.0–24.3%). The monoterpene hydrocarbon content of the flower oil (47–3%) was much higher than in leaf oil (7.4%), while the oxygenated compounds were much higher in leaf oil (71.5%)

AbstractAs a part of our research on essential oil composition of plants from San Luis, Argentina, we have examined the effect of harvesting period on the essential oil composition. The period ranging from February (summer) to April (autumn), gave the best yield in autumn. The oil from Lippia aff. juneliana(Mold.) Tronc. produced in the autumn was found to contain higher amounts of oxygenated compounds than the oil produced in summer. The oils have piperitenone oxide (22.9% and 47.7%), limonene (26.8% and 19.9%) and trans-dihydrocarvone (0% and 16.0%) as major components, respectively.

AbstractThe essential oil obtained by hydrodistillation from the aerial parts of Wedelia glauca(Asteraceae) growing in San Luis, Argentina, was analyzed by GC and GC/MS. Forty-two compounds were identified. The oil was found to be rich in monoterpene hydrocarbons (near 94.9%), such as limonene (38.0%), sabinene (23.9%) and α-pinene (22.0%), which were the main components.

AbstractThe essential oil of Baccharis coridifoliaD.C., obtained by hydrodistillation of the aerial part of female plants in flowering-fructification, was analyzed by GC (retention indices) and GC/MS. The analysis revealed the presence of 29 compounds (89.2% of the oil) of which isocaryophyllene (34.3%), β-caryophyllene (10.8%), caryophyllene oxide (9.8%) and β-selinene (8.2%) were the major components

AbstractThe essential oil of Heterotheca latifoliaBuckley (Compositae) was screened for its antimicrobial activity against Staphylococcus aureus, Escherichia coli, Bacillus subtillis, Candida albicansand Aspergillus niger. Solid phase tests were carried out using petri dishes and applying the agar dilution method for bacteria and the agar diffusion method with paper disks for fungi. H. latifoliaoil was found to possess antimicrobial activity against Bacillus subtillisand Escherichia coli.