The antimicrobial effects of Citrus limonum and Citrus aurantium essential oils on multi-species biofilms

The aim of this study was to evaluate the effects of Citrus limonum and Citrus aurantium essential oils (EOs) compared to 0.2% chlorhexidine (CHX) and 1% sodium hypochlorite (NaOCl) on multi-species biofilms formed by Candida albicans, Enterococcus faecalis and Escherichia coli. The biofilms were grown in acrylic disks immersed in broth, inoculated with microbial suspension (106 cells/mL) and incubated at 37°C / 48 h. After the biofilms were formed, they were exposed for 5 minutes to the solutions (n = 10): C. aurantium EO, C. limonum EO, 0.2% CHX, 1% NaOCl or sterile saline solution [0.9% sodium chloride (NaCl)]. Next, the discs were placed in sterile 0.9% NaCl and sonicated to disperse the biofilms. Tenfold serial dilutions were performed and the aliquots were seeded onto selective agar and incubated at 37°C / 48 h. Next, the number of colony-forming units per milliliter was counted and analyzed statistically (Tukey test, p ≤ 0.05). C. aurantium EO and NaOCl inhibited the growth of all microorganisms in multi-species biofilms. C. limonum EO promoted a 100% reduction of C. albicans and E. coli, and 49.3% of E. faecalis. CHX was less effective against C. albicans and E. coli, yielding a reduction of 68.8% and 86.7%, respectively. However, the reduction of E. faecalis using CHX (81.7%) was greater than that obtained using C. limonum EO. Both Citrus limonum and Citrus aurantium EOs are effective in controlling multi-species biofilms; the microbial reductions achieved by EOs were not only similar to those of NaOCl, but even higher than those achieved by CHX, in some cases.

Eficiência de óleos essenciais de canela e cravo-da-índia como sanitizantes na indústria de alimentos

Os sanitizantes químicos tradicionais utilizados na indústria de alimentos apresentam, como desvantagem, o possível desenvolvimento de resistência e adaptação bacteriana, interferindo na eficiência bactericida mínima destes produtos. Os óleos essenciais com atividade antimicrobiana despertam grande interesse na indústria de alimentos, pela possível utilização como princípios ativos de sanitizantes. Esta pesquisa objetivou determinar a concentração inibitória mínima (CIM) dos óleos essenciais (OEs) de cravo-da-índia e canela contra bactérias Gram positivas (Staphylococcus aureus e Listeriamono cytogenes) e Gram negativas (Escherichia coli e Salmonella sp.) e compará-la com a CIM do hipoclorito de sódio, além de determinar a concentração bactericida mínima (CBM) dos OEs para L. monocytogenes. Foi utilizado o método da microdiluição e os OEs foram caracterizados, quimicamente, por cromatografia gasosa - espectrometria de massa. Os componentes principais dos OEs de canela e cravo-da-índia foram o cinamaldeído (67,58%) e o eugenol (77,58%), respectivamente. A CIM do OE de canela foi de 0,04%, para as bactérias Gram positivas, e < 0,02%, para a bactérias Gram negativas. O OE de cravo-da-índia teve CIM de 0,04% para Salmonella sp., 0,06% para E. coli e S. aureus e 0,08% para L. monocytogenes. Para todas as bactérias testadas, a CIM do hipoclorito de sódio foi > 0,2%. A CBM para L. monocytogenes, no OE de cravo-da-índia, foi de 0,18% e o OE de canela destacou-se por apresentar CBM < 0,02%, demonstrando a possibilidade do uso destes OEs, principalmente o de canela, como princípios ativos de sanitizantes.

Antimicrobial activity of essential oils

Natural products have been studied aiming to understand their biological properties. Thus, this study aimed to investigate the antimicrobial activity of twenty-seven essential oils (EOs) used in aromatherapy procedures, a natural therapy with great emphasis currently used against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa strains. The agar dilution method was carried out and minimal inhibitory concentration against 50% and 90% of strains (MIC50% and MIC90% values) were reported. The S.aureus strains were highly susceptible with MIC90% from 0.21mg/mL to black pepper (Piper nigrum) and tea tree (Melaleuca alternifolia) to 26.52mg/mL with copaiba (Copaifera officinalis) EO. Cinnamon (Cinnamomum cassia) and clove (Syzygium aromaticum) EOs were effective against E.coli (2.0mg/mL) while the S.aromaticum EO was against P.aeruginosa (8.29mg/mL). Thus, the higher susceptibility of Gram-positive bacteria when compared with Gram-negative strains was found, and a large variability in the potential antibacterial has also been observed.

Dynamical evolution of V-type photometric candidates in the outer main belt

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos dos derivados vegetais de condimentos nas características de qualidade e vida de prateleira de linguiça de frango fresca

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Uso de probiótico e óleos essenciais na ração sobre a microbiota intestinal, atividade de enzimas digestivas e a expressão de genes relacionados aos processos de digestão e absorção de nutrientes em frangos

Pós-graduação em Zootecnia - FCAV

Fluorescence Level of Composites Assessed by Computer Processing of Digital Images - ScanWhite

The human dentition is naturally translucent, opalescent and fluorescent. Differences between the level of fluorescence of tooth structure and restorative materials may result in distinct metameric properties and consequently perceptible disparate esthetic behavior, which impairs the esthetic result of the restorations, frustrating both patients and staff. In this study, we evaluated the level of fluorescence of different composites (Durafill in tones A2 (Du), Charisma in tones A2 (Ch), Venus in tone A2 (Ve), Opallis enamel and dentin in tones A2 (OPD and OPE), Point 4 in tones A2 (P4), Z100 in tones A2 ( Z1), Z250 in tones A2 (Z2), Te-Econom in tones A2 (TE), Tetric Ceram in tones A2 (TC), Tetric Ceram N in tones A1, A2, A4 (TN1, TN2, TN4), Four seasons enamel and dentin in tones A2 (and 4SD 4SE), Empress Direct enamel and dentin in tones A2 (EDE and EDD) and Brilliant in tones A2 (Br)). Cylindrical specimens were prepared, coded and photographed in a standardized manner with a Canon EOS digital camera (400 ISO, 2.8 aperture and 1/ 30 speed), in a dark environment under the action of UV light (25 W). The images were analyzed with the software ScanWhite©-DMC/Darwin systems. The results showed statistical differences between the groups (p < 0.05), and between these same groups and the average fluorescence of the dentition of young (18 to 25 years) and adults (40 to 45 years) taken as control. It can be concluded that: Composites Z100, Z250 (3M ESPE) and Point 4 (Kerr) do not match with the fluorescence of human dentition and the fluorescence of the materials was found to be affected by their own tone.

Assessment of antimicrobial activity of cinnamon (Cinnamomum zeylanicum) essential oil combined with EDTA and polyethylene glycol in yogurt

Essential oils (EOs) are technological options that may be employed in natural foods due to their antimicrobial activities. However, restrictions exist when high EOs concentrations are required which, in their turn, affect sensory qualities. Technological alternatives, such as combination of EOs with chelating and dispersing agents, have been proposed in the literature. Current research determined the antimicrobial activity of cinnamon EO against microbial spoilage in yogurt when added at the highest acceptable sensory EO concentration, alone or associated with ethylenediaminetetraacetic acid (EDTA) and/or polyethylene glycol. Cinnamon EO's chemical analysis was performed by gas chromatography-mass spectrometry (GC-MS). Sensory analysis was conducted to define the highest acceptable sensory concentration of cinnamon EO in yogurt, stipulated at 0.04% cinnamon EO. Antimicrobial activity in yogurt was then evaluated for aerobic mesophiles, psychrotrophilic microorganisms, yeasts and molds counts. Treatments comprised (1) control, (2) 0.04% EO, (3) 0.04% EO + 0.01% EDTA, (4) 0.04% EO + 0.02% polyethylene glycol; (5) 0.04% EO + 0.01% EDTA + 0.2% polyethylene glycol, in triplicates. Concentration 0.04% of cinnamon EO, alone or associated with EDTA and/or polyethylene glycol, failed to show any antimicrobial activity against aerobic mesophiles, yeasts and molds.

Utilização do choque osmótico na avaliação da viabilidade de sêmen criopreservado de ovinos

This study evaluated the use of hipoosmotic swelling test (HOST) with deionized water (0 mOsmol), as a method of post thaw ram semen evaluation and correlate their findings with different techniques of semen evaluation. Therefore, twenty semen samples of 20 different adult rams were assessed as for kinetic sperm parameters through computerized system (IVOS 12, Hamiton Thorn Biosciences, Beverly, MA, EUA) and subjective analysis. The sperm membranes viability was carried out by the association of fluorescent probes (propidium iodide, JC-1 and FITC-PSA). The structural integrity of the plasma membrane was also studied through supravital test with eosin and the functional integrity of membrane evaluated by doing the hipoosmotic swelling test with deionized water (0 mOsmol), in the following proportions: One part of semen for 10 (HOST 10), 50 (HOST 50) and 100 (HOST 100) parts of water. After semen dilution in the different proportions it was fixed in formalin-buffered saline and analyzed with regard to percentage of HOST reactive sperm (bent/coiled). The percentage of reaction obtained for HOST 10 (33,1%); HOST 50 (32,8%) and HOST 100 (31,8%) did not differ significantly. HOST 10 presented positive correlation with the plasma membrane integrity by the EOS (r = 0,80; p < 0,05). Positive correlations between HOST 50 and HOST 100 with sperm subpopulation with membrane integrity by fluorescence were observed (r = 0,83 and r = 0,85; p < 0,01). The findings suggest that the HOST with deionized water can provide additional information for post thawing ram sperm viability evaluation.