Antimicrobial activity and acute and chronic toxicity of the essential oil of Lippia origanoides

Currently, there is a growing interest in medicinal plants, because of an increased demand for alternate therapies. In this study, the antimicrobial activity and toxicity of the essential oil of Lippia origanoides (L. origanoides) were investigated. The essential oil of L. origanoides was extracted by steam-dragging distillation and its constituents were identified by chromatography coupled with mass spectrometry. Among the 15 compounds identified, the most abundant were carvacrol (29.00%), o-cymene (25.57%), and thymol methyl ether (11.50%). The essential oil was studied in antimicrobial assays to determine the MIC and MBC. The results indicated that a concentration of 120μL/mL of oil was sufficient to inhibit the growth of the following microorganisms: Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923) and Salmonella cholerasuis (ATCC 10708). Acute and chronic toxic effects of orally administered oil were investigated in Wistar rats by using standard methods. Doses of 30, 60 and 120mg/kg of the essential oil did not induce significant changes in weight, behavior or hematological and biochemical parameters in the animals. There were no signs of any histopathological changes to the liver, kidneys or heart of the treated rats, suggesting that Lippia origanoides oil is non-toxic after oral administration in acute or chronic toxicity studies. The results obtained in this study show that the essential oil of L. origanoides has a high safety margin, with no detectable toxic effects in rats treated with doses to 120mg/kg. In addition, L. origanoides oil demonstrated potent antimicrobial activity against S. aureus, E. coli and S. cholerasuis. Based on these findings, this essential oil may have practical application as a veterinary antimicrobial

Effect Of Chloride And Copper Ions On Corrosion Of 5182 Aluminum Alloy

This work aimed to study the corrosion behavior of 5182 aluminum alloy (Al-Mg), widely used in the end production of carbonated beverage cans, in the presence of corrosion catalyst ions: copper and chloride. Firstly, acidity, pH, chloride and copper ions concentration data in soft drinks were collected to define the model solutions with pH at 3.0 using citric acid. The concentration of chloride ions in the model solution ranged from zero to 1000 mg kg -1, while the concentration of copper ranged from zero to 1000 μg kg-1. After contact with the de-aerated model solution, the aluminium sample was evaluated by polarization curves and by scanning electron microscopy. Once that evolving corrosion was observed in materials which had been in contact with all concentrations studied, it can be concluded that the studied level of chloride and copper in soft drinks is enough to provide a favourable medium to development of corrosion.500507Lansmont Field-to-LabFontana, M.G., (1986) Corrosion Engineering, p. 555. , 3rd ed., New York: McGraw-Hill, IncRamanathan, L.V., (2004) Corrosão e Seu Controle, , Ed. Hemus 1a Ed., São PauloSzklarska-Smialowska, Z., Pitting corrosion of aluminium (1999) Corrosion Science, 41, pp. 1743-1767Badran, M.M.H., El Azhari, A.A., Khedr, M.G.A., Pitting corrosion behavior of aluminium in water desalination plants (1989) Desalination, 72, pp. 351-366Bakos, I., Szabó, S., Corrosion behavior of aluminium in copper containing environment (2008) Corrosion Science, 50, pp. 200-205Seruga, M., Hasenay, D., Corrosion of aluminium in soft drinks (1996) Zeitschrift für Lebensmitteluntersuchung und -Forschung A, 202 (4), pp. 308-312(2010) G3 - 89 (Reapproved 2010): Standard Practice for Conventions Applicable to Electrochemical Measurements in Corrosion Testing, , ASTM - American Society for Testing and Materials. West ConshohockenAl Mayouf, A., Al Fuhaiman, L., Suhaibani, A., Corrosion of aluminium in ascorbic, citric and tartaric acids with and without chloride ions (2008) Anti-Corrosion Methods and Materials, 55 (2), pp. 79-85Blanc, C., Mankowski, G., Susceptibility to pitting corrosion of 6056 aluminium alloy (1997) Corrosion Science, 39 (5), pp. 949-959Wong, K.P., Alkire, R.C., Local chemistry and growth of single corrosion pits in aluminum (1990) J. Electrochem. Soc., 37 (10), pp. 3010-3015McCafferty, E., The electrode kinetics of pit initiation on aluminium (1995) Corrosion Science, 37 (3), pp. 481-492Guillaumin, V., Mankowski, G., Localized corrosion of 2024 T351 aluminium alloy in chloride media (1999) Corrosion Science, 41, pp. 421-43

Acaricidal activity of leaves of Morus nigra against the cattle tick Rhipicephalus microplus

ABSTRACT The acaricidal activity of crude ethanolic extract and fractions from the leaves of Morus nigra (Moraceae) was carried out on female cattle ticks Rhipicephalus microplus, using the adult immersion test. The mortality and fertility of females exposed to different concentrations of hexane, chloroform and ethyl acetate fractions, as well as ethanolic extract of M. nigra with concentrations of 5, 10 and 25mg/ml were evaluated using three treatment groups, two control groups and triplicate tests. The study also identified the main phenolic compounds of the extract and fractions of this species by HPLC. The chloroform fraction of leaves of M. nigra (25mg/mL) showed the best results for this species, obtaining 62.6% of inhibition of oviposition, 39.3% of eggs eclosion average and 65.4% of effectiveness. HPLC analysis revealed the presence of phenolic compounds, which may be related to biological activity shown by the extracts, which can be used as an alternative control against R. microplus adult tick