Effect of polycaprolactone nanocapsules loaded with essential oils on biofilm formation by Staphylococcus aureus strains isolated from bovine mastitis cases

Abstract Bovine infectious mastitis is largely resistant to antibacterial treatment, mainly due to mechanisms of bacterial resistance in the biofilms formed by Staphylococcus aureus. Melaleuca (MEO) and citronella essential oils (CEO) are promising agents for reducing or eliminating biofilms. Free melaleuca oil presented a medium Minimum Inhibitory Concentration (MIC) of 0.625% and a Minimum Bactericidal Concentration (MBC) of 1.250%, while free citronella oil showed medium MIC and MBC of 0.313%. Thus, free CEO and MEO demonstrate bacteriostatic and bactericidal potential. We generated polymeric nanocapsules containing MEO or CEO and evaluated their efficacy at reducing biofilms formed by S. aureus. Glass and polypropylene spheres were used as test surfaces. To compare the responses of free and encapsulated oils, strains were submitted to 10 different procedures, using free and nanoencapsulated essential oils (EOs) in vitro. We observed no biofilm reduction by MEO, free or nanoencapsulated. However, CEO nanocapsules reduced biofilm formation on glass (p=0.03) and showed a tendency to diminish biofilms on polypropylene (p=0.051). Despite nanoencapsulated CEO reducing biofilms in vitro, the formulation could be improved to modify the CEO component polarity and, including MEO, to obtain more interactions with surfaces and the biofilm matrix

Development of a liquid-liquid microextraction GC-MS method for simultaneous determination and pharmacokinetic analysis of β- elemene in rat plasma after administration of citronella grass extract / 药学学报

We established a simple and sensitive GC-MS method for the determination of β-elemene in rat plasma and measured the pharmacokinetics of citronella grass extract in rats. Plasma samples were pretreated using liquid-liquid microextraction: 100 μL of plasma sample (containing naphthalene as the internal standard) was extracted with 50 μL of n-hexane. The determination was performed on DB-5ms column (30 m×0.25 mm, 0.25 μm). The initial column temperature was 60 ℃ and raised to 160 ℃ at a rate of 50 ℃·min-1, maintained for 3 min, and finally increased to 260 ℃ for 3 min. Helium was the carrier gas and the flow rate was 0.15 mL·min-1. The injection volume was 2 μL. EI and selected monitored ions pattern were used for ion scanning with m/z 128 (naphthalene) and m/z 93 (β-elemene). Citronella grass extract was administered to rats by intragastric administration and intravenous administration (containing β-elemene 55 mg·kg-1), and plasma was collected and prepared using an automated blood collection system. The linear range of β-elemene in plasma was 1.0-250 ng·mL-1 (r = 0.997), the limit of quantification was 1.0 ng·mL-1, the accuracy was -4.47% - -0.85%, the extraction recovery was between 56.02%-66.89%, and no obvious matrix effect (94.28%-108.63%) was found. The main pharmacokinetic parameters of β-elemene were AUC0-t (23.56 ± 4.40) ng·mL-1, tmax (1.67 ± 0.58) h, Cmax (7.36 ± 0.69) ng·mL-1, MRT0-t (2.76 ± 0.27) h, t1/2z (2.73 ± 1.36) h, Vz (7.39 ± 3.18) L·kg-1, CLz (1.95 ± 0.51) L·h-1·kg-1, and the absolute bioavailability was about 8.78%. The method is simple, accurate, and sensitive, and is suitable for the pharmacokinetic analysis of β-elemene in citronella grass extract in rats. All animal studies were implemented according to protocols, which were reviewed and approved by the Institutional Animal Care and Use Committee at Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences.

Effects Of Alpha-Mangostin And Citronella Oil Against Acne Causing Bacteria

Objective: This study assessed the effects of alpha-mangostin (AM) and citronella oil (CO) working alone or in combination against Propionibacterium acnes (P. acnes) and Staphylococcus aureus (S. aureus). Methods: The screening for antibacterial activity of AM and CO against P. acnes and S. aureus was carried out using the disk diffusion method. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of these two substances were determined using the broth microdilution method. The fractional inhibitory concentration indices (FICI) of a combination of AM and CO were obtained by checkerboard dilution assay. Results: The results showed that alpha-mangostin and citronella oil do indeed fight against P. acnes and S. aureus. The MICs and MBCs of AM against P. acnes and S. aureus were the same at 6.25 and 50 µg/ml, respectively. Both the MIC and the MBC of CO against P. acnes were 27.81µg/ml. The MIC and the MBC of CO against S. aureus were 112.13 and 224.25 µg/ml, respectively. The FICI of a combination of AM and CO against P. acnes and S. aureus were 2.00, indicating indifferent interaction with no additional inhibitory effect. Conclusion: AM and CO are very effective against P. acnes and S. aureus, nevertheless their effect when used together was indifferent from using alone. Further research may find that either or both of these substances combined with yet a different natural agent could provide synergy againstP. acnes and S. aureus.

Efeito moluscicida do óleo essencial de Cymbopogon winterianus Jowitt (Poaceae) sobre Lymnaea columella (Say, 1817) e Biomphalaria tenagophila (D'Orbigny, 1835) / Molluscicidal effect of essential oil of Cymbopogon winterianus Jowitt (Poaceae) on Lymnaea columella (Say, 1817) and Biomphalaria tenagophila (D'Orbigny, 1835)

RESUMO O uso das substâncias moluscicidas convencionais no controle de planorbídeos vetores constitui-se uma importante ferramenta no combate da fasciolose hepática e esquistossomose. Sendo, portanto, de extrema relevância para a pecuária e para os serviços de Vigilância Epidemiológica. Por outro lado, a seleção de caramujos resistentes a tais substâncias e sua baixa seletividade estimulam a busca por novas substâncias. Neste sentido, o presente trabalho foi desenvolvido para avaliar o efeito do óleo essencial de Cymbopogon winterianusJowitt sobre Lymnaea columella e Biomphalaria tenagophila, hospedeiros intermediários de Fasciola hepatica e esquistossomose mansônica, respectivamente. O óleo essencial foi extraído a partir de folhas frescas utilizando o sistema Clevenger. A análise qualitativa foi realizada por meio de cromatografia gasosa acoplada a espectrometria de massas (CG/EM) e a quantificação dos constituintes presentes no óleo foi determinada por cromatografia gasosa acoplada ao detector de ionização de chama (CG/DIC). O efeito moluscicida foi avaliado utilizando seis moluscos de cada espécie e o óleo essencial de C. winterianus nas concentrações finais de 10, 20, 30, 40, 60, 80 e 100 ppm. A análise por cromatografia gasosa do óleo essencial possibilitou a identificação dos componentes majoritários geraniol (28,62%), citronelal (23,62%) e citronelol (17,10%). Os valores de DL100 e DL50para os moluscos das espécies L. columella e B. tenagophila foram, respectivamente, 60 e 40 ppm; 80 ppm e 60 ppm. O óleo de Cymbopogon winterianus demonstrou-se uma alternativa promissora para o controle dos moluscos, sendo a espécie L. columella mais sensível ao mesmo.

ABSTRACT Conventional molluscicides have been employed to control of planorbids vectors and are an important tool in order to control the hepatic fascioliasis and schistosomiasis. Thus, these substances have been showinggreat relevance for both Veterinary and Livestock Services as well as for Epidemiology and Disease Surveillance. On the other hand, the process of drug pressure for the selection of resistant snails to such components and their low selectivity have stimulated the search for new substances. Since researches on new drugs are the starting point to assist on themolluscs control, this work was developed in order to evaluate the effect of Cymbopogon winterianus Jowitt essential oil on L. columella and B. tenagophila, intermediate hosts of Fasciola hepatica and Schistosoma mansoni, respectively. The essential oil was obtained from fresh leaves by hydrodistillation using a Clevenger apparatus. A qualitative analysis was performed by gas chromatography together with a mass spectrometry one (GC/MS) and the chemical constituent content was determined by gas chromatography with a flame ionization detector (GC/FID). The molluscicidal effect was evaluated through the use of six snails of each species and C. winterianus essential oil at 10, 20, 30, 40, 60, 80 and 100 ppm. The result of the gas chromatographic analysis for the essential oil showed geraniol (28.62%), citronellal (23.62%) and citronellol (17.10%) as the major chemical components . The DL100 and DL50 values for L. columella and B. tenagophila species were, respectively, 60 and 40 ppm; 80 ppm and 60 ppm. L. columella had demonstrated more sensitivity to this essential oil than theB. tenagophila species. The C. winterianus essential oil proved to be a promising alternative for the control of these molluscs being the L. columella species the most sensitive of them.

Biological activities and acute oral toxicity of citronella and lemongrass oil / 대한수의학회지

This study was performed to investigate the antibacterial, antioxidant, and termite repellent effects of citronella oil (CiO) and lemongrass oil (LO). When the antibacterial activity against Staphylococcus (S.) aureus with various levels of antibacterial resistance were tested, a 0.05% concentration of CiO and LO completely inhibited the growth of all tested S. aureus strains. Evaluation of the antioxidant effect demonstrated that the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of CiO was 2~3 times greater than that of LO. Among trial products made with various combinations of CiO and LO, a CiO : LO ratio of 6 : 4 had the most potent termite repellent effects. Assessment of acute toxicity of the trial product showed that the LD50 was more than 2,000 mg/kg. Based on the above results, CiO and LO have antibacterial, antioxidant, and termite repellent activities. Therefore, both compounds could be potential termites repellent reagents.

In vitro evaluation of the resistence of the Contracaecum sp. larvae (Railliet & Henry, 1912) (Nematoda: Anisakidae), to the essential oil of citronella ( Cymbopogon sp.) (Poaceae)

The essential oil of citronella ( Cymbopogon sp.) was used in vitro to assess its influence on the L3 larvae of Contracaecum sp. The parameters investigated were the morphological integrity and motility of the larvae after being in contact with the product. The essential oil was very effective in its trade form killing all the larvae at the utmost in two hours. The damage caused to the larvae was evaluated with a microscope in histological cuts, where cuticular rupture and disintegration of the intestinal wall of the larvae were found. The results were analyzed through the use of a monocaudal Fisher test to detect differences between the groups where the significance of p<0,05 was obtained.

O óleo essencial de citronela ( Cymbopogon sp.) foi utilizado in vitro para avaliar sua ação sobre larvas L3 de Contracaecum sp. Os parâmetros observados foram motilidade e integridade morfológica das larvas após contato com o produto. O óleo essencial demonstrou-se bastante eficaz, em sua forma comercial, causando morte de todas as larvas em no máximo duas horas. Os danos causados às larvas foram avaliados microscopicamente em cortes histológicos, encontrando-se ruptura cuticular e lise da parede intestinal das larvas. Os resultados foram analisados através da aplicação do teste de Fisher monocaudal para detectar diferenças entre os grupos, onde se obteve uma significância de p<0,05.