Concentrations Of Eugenol Research Articles

Comparative efficacy of benzocaine, tricaine methanesulfonate and eugenol as anesthetic agents in the guppy Poecilia vivipara

The aim of this study was to evaluate the anesthetic efficacy and determine the lowest effective concentration in the guppy, Poecilia vivipara. Fishes were exposed to benzocaine, tricaine methanesulfonate and eugenol at three different concentrations. After induction, they were transferred to an aquarium free of anesthetic for evaluating their recovery time. At the lowest concentration of the three anesthetics (50mgL−1), fish did not reach complete induction. Time to accomplish a light sedation stage was significantly negative-related with concentration using tricaine (145±13.4s with 50mgL−1 to 4.7±0.7s with 200mgL−1) and benzocaine (152.8±13s with 50mgL−1 to 4.0±0.9s with 200mgL−1). For eugenol, significant differences were found between the lowest concentration, 50mgL−1 (241±57.6s) with 100mgL−1 (13.3±3.9s) and 200mgL−1 (9.5±2.6s). Recovery times were significantly longer (P<0.05) with the increase of eugenol concentration from 100mgL−1 to 200mgL−1, with no differences found between the different concentrations of benzocaine and tricaine. Complete induction times were significantly greater (P<0.05) when using eugenol comparing with the other two anesthetic agents in fish exposed at the highest concentrations (200mgL−1). This parameter showed a great dispersion when using eugenol at this concentration. Three fish exposed to 200mgL−1 of eugenol did not recovered from the anesthetic after 180s and presented ventilatory failure. Significantly shorter recovery times (P<0.05) were found using tricaine comparing with eugenol (120±24.8s and 163.5±57.1s, respectively) at the higher concentration (200mgL−1). The optimum dose rates of benzocaine and tricaine for induction within the efficacy criteria stated in this study was 200mgL−1. It can be concluded these anesthetics are the more effective ones, being benzocaine more economically affordable for large-scale use on handling P. vivipara.

Evaluation of synergistic and antagonistic effects between some selected antioxidants by means of an electrochemical technique

SummaryThis work presents a systematic study of the possible interactions in mixtures of the natural antioxidants eugenol, thymol, sesamol and limonene. The antioxidant capacity is measured from the decrease of the DPV signal corresponding to the H2O2 oxidation on a mercury electrode in the presence of the antioxidants. A three‐level full factorial design was used to analyse the antioxidant capacity of forty five mixtures. The higher synergistic effect was reached in the mixtures containing eugenol and sesamol (antioxidant capacity increases in a 28.5%). The synergistic and antagonistic effects of the combinations having the lower antioxidant capacity (thymol, sesamol and limonene) ranged between 20.2–26.3% and 8.6–11.8%, respectively. An increase in the eugenol concentration implies a progressive increase in the global synergy, not proportional to the concentration. A possible explanation of the synergy related to the oxidation mechanisms and to the possibility of interaction with the radicals is given.

Critical Concentration of Lecithin Enhances the Antimicrobial Activity of Eugenol against Escherichia coli.

Lecithin is a natural emulsifier used in a wide range of food and nonfood applications to improve physical stability, with no known bioactive effects. In this study, the effect of lecithin on the antimicrobial performance of a constant eugenol concentration was tested against three Escherichia coli strains (C600, 0.1229, and O157:H7 strain ATCC 700728). This is the first study, to our knowledge, focusing on lecithin at concentrations below those commonly used in foods to improve the stability of oil in water emulsions (≤10 mg/100 ml). For all three cultures, significant synergistic antimicrobial effects were observed when E. coli cultures were exposed to a constant eugenol concentration (ranging from 0.043 to 0.050% [wt/wt]) together with critical lecithin concentrations ranging from 0.5 to 1 mg/100 ml. Increasing the concentration of lecithin above 1 mg/100 ml (up to 10 mg/100 ml lecithin) diminished the antibacterial effect to values similar to those with eugenol-only treatments. The formation of aggregates (<100 nm) at the critical lecithin concentration was observed using cryo-transmission electron microscopy (cryo-TEM), together with a reduction in light absorbance at 284 nm. At critically low concentrations of lecithin, the formation of nanoscale aggregates is responsible for improving eugenol antimicrobial effects.IMPORTANCE Essential oils (EOs) are effective natural antimicrobials. However, their hydrophobicity and strong aromatic character limit the use of essential oils in food systems. Emulsifiers (e.g., lecithin) increase the stability of EOs in water-based systems but fail to consistently improve antimicrobial effects. We demonstrate that lecithin, within a narrow critical concentration window, can enhance the antimicrobial properties of eugenol. This study highlights the potential bioactivity of lecithin when utilized to effectively control foodborne pathogens.

Safety of AQUI‐S 20E (10% Eugenol) as a Sedative for Freshwater Fish

AbstractAQUI‐S 20E (10% eugenol) has been shown to be an effective fish sedative for freshwater finfish, but to be approved for use in the United States, the U.S. Food and Drug Administration must be provided with data demonstrating the product is safe to treated animals. Accordingly, we evaluated the safety of AQUI‐S 20E when used to sedate Rainbow Trout Oncorhynchus mykiss, Yellow Perch Perca flavescens, and Channel Catfish Ictalurus punctatus. After identifying the highest effective concentrations likely to be used by fisheries biologists to sedate each species to handleable, replicate groups of fish were exposed to this intended concentration (1×) or a 50% higher eugenol concentration (1.5×) for periods of time adequate to effectively sedate 80% of fish to handleable (ET80) or for predetermined treatment periods exceeding the ET80. These predetermined treatment doses (40 and 60 mg eugenol/L for Rainbow Trout, 80 and 120 mg eugenol/L for Yellow Perch, and 100 and 150 mg eugenol/L for Channel Catfish), treatment periods (2.25–8.75 min for Rainbow Trout, 4.0–10.5 min for Yellow Perch, and 2.5–12.0 min for Channel Catfish; specific treatment periods depending on doses), and ET80 values were used to establish margins of safety for each species. An adequate margin of safety was defined as treatment periods ≥ 3–4 min longer than the 1× ET80 and ≥ 2–3 min longer than 1.5× ET80 after which fish survival was ≥ 95%. Based on survival, there was an adequate margin of safety associated with overexposing fish to AQUI‐S 20E. Given the absence of biologically relevant effects of AQUI‐S 20E exposure on tissue histology, there is no evidence to suggest that the survival‐based margins of safety should be revised to be more conservative. Our results indicate there is an adequate margin of safety associated with the use of AQUI‐S 20E to sedate freshwater fish to handleable.Received September 27, 2016; accepted December 27, 2016 Published online March 15, 2017

Live Transport of Yellow Perch and Nile Tilapia in AQUI‐S 20E (10% Eugenol) at High Loading Densities

AbstractFish transport costs are a substantial portion of the operational expenses for aquaculture facilities in the USA. Safely transporting higher loading densities of fish would benefit haulers by increasing efficiency and reducing costs, but research evaluating transport for individual species is generally lacking. In this study, Yellow Perch Perca flavescens and Nile Tilapia Oreochromis niloticus were transported for 6 h immersed in water containing AQUI‐S 20E (10% eugenol) at fish loading densities of 240 g/L (2 lb/gal) for perch and 480 g/L (4 lb/gal) for tilapia. Survival was quantified for fish transported in AQUI‐S 20E concentrations of (1) control or 0 mg/L of water, (2) 100 mg/L, or (3) 200 mg/L. Yellow Perch had 98–100% survival, and Nile Tilapia had 100% survival up to through 14 d after transport across all AQUI‐S 20E levels, including the control. Eugenol concentrations decreased rapidly in transport tank water, and fish showed no signs of sedation by the end of transport. We conclude that live transport of Yellow Perch and Nile Tilapia at higher loading densities resulted in high survival regardless of the AQUI‐S 20E concentrations we tested.

Chemosensitivity of MCF-7 cells to eugenol: release of cytochrome-c and lactate dehydrogenase

Phytochemicals have been extensively researched for their potential anticancer effects. In previous study, direct exposure of rat liver mitochondria to eugenol main ingredient of clove, uncoupled mitochondria and increased F0F1ATPase activity. In the present study, we further investigated the effects of eugenol on MCF-7 cells in culture. Eugenol demonstrated: a dose-dependent decrease in viability (MTT assay), and proliferation (real time cell analysis) of MCF-7 cells, (EC50: 0.9 mM); an increase in reactive oxygen species; a decrease in ATP level and mitochondrial membrane potential (MitoPT JC-1 assay); and a release of cytochrome-c and lactate dehydrogenase (Cytotoxicity Detection Kit PLUS) into culture media at eugenol concentration >EC50. Pretreatment with the antioxidants Trolox and N-acetyl cysteine partially restored cell viability and decreased ROS, with Trolox being more potent. Expression levels of both anti- and pro-apoptotic markers (Bcl-2 and Bax, respectively) decreased with increasing eugenol concentration, with no variation in their relative ratios. Eugenol-treated MCF-7 cells overexpressing Bcl-2 exhibited results similar to those of MCF-7. Our findings indicate that eugenol toxicity is non-apoptotic Bcl-2 independent, affecting mitochondrial function and plasma membrane integrity with no effect on migration or invasion. We report here the chemo-sensitivity of MCF-7 cells to eugenol, a phytochemical with anticancer potential.

Eugenol inhibits quorum sensing and biofilm of toxigenic MRSA strains isolated from food handlers employed in Saudi Arabia

ABSTRACTFood handlers are important component in assessment and maintenance of food quality as they are carriers of food pathogens causing spoilage. Food spoilage is attributed to quorum sensing (QS) controlled development of biofilms. Therefore, there is an urgent need to develop novel QS and biofilm inhibitors to prevent spoilage of food products. In the present study, toxin producing biofilm forming methicillin-resistant Staphylococcus aureus (MRSA) were isolated from food handlers. Further, eugenol was screened for its QS and anti-biofilm properties. Analysis of nasal and hand swabs revealed the presence of seven toxigenic and biofilm forming MRSA strains. Eugenol demonstrated significant anti-QS activity in CVO26 and also reduced the QS-regulated production of elastase, protease, chitinase, pyocyanin and exopolysaccharide (EPS) in PAO1 considerably. Eugenol demonstrated 17%–86%, 24%–69%, 30%–91%, 9%–94% and 4%–89% reduction in biofilm biomass of S. aureus ATCC 25923 and MRSA strains FSA3, FSA11, FSA13 and FSA32, respectively. Sub-inhibitory concentrations of eugenol also decreased the metabolic activity in biofilm cells. Molecular docking analysis showed high binding affinity of eugenol that represents its biofilm inhibitory activity. This is the first report on the carriage of toxigenic drug-resistant biofilm forming S. aureus by food handlers and inhibition of their biofilms in the Kingdom of Saudi Arabia. The findings give a clear insight into the food safety hazards associated with the carriage of S. aureus and present eugenol as a broad-spectrum anti-QS and anti-biofilm agent.

Nanoemulsion: A suitable nanodelivery system of clove oil for anesthetizing Nile tilapia.

Clove oil ethanolic solution (CL-EtOH) have always been used for fish anesthesia. However, ethanol causes major side effect of fish hypersensivity. In this study, clove oil loaded nanoemulsion (CLN) was developed in order to enhance water miscibility of clove oil without using ethanol in the preparations. The obtained CLN was characterized in terms of droplet size, size distribution expressed as polydispersity index (PDI), and zeta potential. The anesthetic effect of CLN in comparison with CL-EtOH on Oreochromis niloticus (Nile tilapia) was investigated. The results showed that the best CLN was composed of 20% w/w clove oil and 15% w/w polysorbate 20. This CLN has internal droplet size of 63.2 ± 1.0 nm, PDI of 0.31 ± 0.04, and zeta potential of - 30.3 ± 8.1 mV. GC-MS analysis indicated that eugenol was the main compound in clove oil. It was found that the induction time to anesthesia for Nile tilapia that received this CLN was shorter than that received CL-EtOH at the same eugenol concentration. The results of this study showed the potential of nanoemulsion on water miscible and efficacy enhancing of clove oil without using ethanol. The obtained CLN from this study is a promising formulation for fish aquaculture where fish sedation is required.

Factors influencing aversive learning in the oriental fruit fly, Bactrocera dorsalis.

Parameters such as the intensity of conditioned and unconditioned stimuli, the inter-trial interval, and starvation time can influence learning. In this study, the parameters that govern aversive learning in the oriental fruit fly, Bactrocera dorsalis, a serious pest of fruits and vegetables, were examined. Male flies were trained to associate the attractive odorant methyl eugenol, a male lure, with a food punishment, sodium chloride solution, and the conditioned suppression of the proboscis-extension response was investigated. We found that high methyl eugenol concentrations support a stronger association. With increasing concentrations of sodium chloride solution, a steady decrease of proboscis-extension response during six training trials was observed. A high level of learning was achieved with an inter-trial interval of 1-10min. However, extending the inter-trial interval to 15min led to reduced learning. No effect of physiological status (starvation time) on learning performance was detected, nor was any non-associative learning effect induced by the repeat presentation of odor or punishment alone. The memory formed after six training trials could be retained for at least 3h. Our results indicate that aversive learning by oriental fruit flies can be affected by odor, punishment concentration and inter-trial interval.

Dual effects of eugenol on the neuronal excitability: An in vitro study

Besides its well-known actions on sensory afferents, eugenol also affects general excitability of the nervous system, but the mechanisms involved in the recent effect, especially through modulation of ion channels, have received much less attention. In this study, we studied the effects of eugenol on the excitability of central neurons of land snail Caucasotachea atrolabiata and tried to elucidate the underlying ionic mechanisms. The lower concentration of eugenol (0.5mM) reversibly reduced the frequency of spontaneous action potentials that was associated with elevation of threshold, reduction of maximum slope of rising phase and prolongation of actin potentials. These effects were mimicked by riluzole, suggesting that they might be mediated by inhibition of Na+ channels. Eugenol also prolonged the single-spike afterhyperpolarization and post stimulus inhibitory period, but these effects seemed to be consequent to action potential prolongation that indirectly augment Ca2+ inward currents and Ca2+-activated K+ currents. This concentration of eugenol was also able to prevent or abolish pentylenetetrazole-induced epileptiform activity. On the other hand, a higher concentration of eugenol (2mM) reversibly increased the frequency of action potentials and then induced epileptiform activity in majority of treated neurons. Several criteria suggest that the inhibition of K+ channels by higher concentration of eugenol and indirect augmentation of Ca2+ currents are central to the hyperexcitability and epileptiform activity induced by eugenol. Our findings indicate that while low concentration of eugenol could have antiepileptic properties, at higher concentration it induces epileptiform activity. It seems that does dependent inhibition of the ionic currents underlying rising and falling phases of action potential is relevant to the eugenol suppressant and excitatory actions, respectively.

In vitro and in vivo recoveries of cutaneous micro-dialysis probe of paeonol, eugenol and piperine

To establish a method for detecting micro-dialysis recovery of paeonol, eugenol and piperine in Huoxue Zhitong patch, in order to provide the basis for further percutaneous pharmacokinetics studies. The concentrations of paeonol, eugenol and piperine in dialysates were determined by HPLC, and probe deliveries were calculated respectively. The effects of concentration and calibration approaches on the micro-dialysis probe deliveries of the three components were investigated, and their probe absorbability, in vitro and in vivo probe stability and repeatability were also studied.The results indicated that little paeonol, eugenol and piperine were observed in probes with 30% alcohol as the perfusate, and could be cleaned from probe in a short time. And the in vivo and in vitro probe deliveries of three components were stable within 8 h, drug-containing solution and blank perfusate were alternatively used for three times, and the in vivo and in vitro probe deliveries of three components were basically unchanged. The in vitro recoveries of paeonol, eugenol and piperine with a range of concentration were respectively (45.7±4.66)%, (27.82±2.95)%, (41.3±3.96)%, which indicated no concentration independent. Under the same conditions, the similar delivery was observed by dialysis, retrodialysis and no-net flux. Therefore, the concentrations of analyses of the collected fraction could be calibrated by in vitro or in vivo recoveries. Meanwhile, this also proved that the micro-dialysis method built by this study is applicable to the study on percutaneous pharmacokinetics of Huoxue Zhitong patch.

Eugenol Toxicity in Human Dental Pulp Fibroblasts of Primary Teeth.

The aim of the study was to determine the eugenol concentrations at which toxicity occurs in human dental pulp fibroblasts of primary teeth. Samples of primary dental pulp tissue were taken. Tissue samples were seeded by means of explant technique and used in the 4(th)-5th pass. Single Cell Gel Electrophoresis (Comet), phenazine MeThoSulfate (MTS), LIVE/DEAD Cell Viability/Toxicity and trypan blue assays for evaluation of the cytotoxicity of increasing concentrations of eugenol (0.06 to 810 μM) were performed. The results of toxicity tests showed toxic effects on dental pulp fibroblasts, even at very low concentrations of eugenol (0.06 μM). Very low concentrations of eugenol produce high toxicity in human dental pulp fibroblasts. All of the concentrations of eugenol that we evaluated produced high toxicity in human dental pulp fibroblasts of primary teeth.

(1‐Butyl‐3‐methylimidazolium Hexafluorophosphate) Based Sensor for Quantification of Eugenol Antioxidant

AbstractA simple, ultrasensitive and convenient electrochemical method has been developed for quantification of antioxidant eugenol, at multi‐walled carbon nanotube (MWCNT) ionic liquid (1‐Butyl 3‐methylimidazolium hexafluorophosphate) glassy carbon based sensor. The electrochemical behavior of eugenol at the sensor was studied using square wave voltammetry as a function of concentration of eugenol. The voltammetric studies of eugenol at MWCNT‐IL‐Gel/GC sensor exhibited a well defined anodic peak for its oxidation in Britton‐Robinson buffer at pH 10.5.Under optimized experimental condition the square wave oxidation peak current was linear over concentration range of 250 nM L−1 to 4000 nM L−1 with limit of detection (LOD) and limit of quantification of 87.6 nM L−1 and 292.2 nM L−1 respectively. The results indicate that the electrode coated with MWCNT‐IL‐Gel possess high sensitivity towards eugenol. Developed MWCNT‐IL‐Gel/GC sensor was successfully employed for the analysis of eugenol in real samples.

English

Essential plant oils contain biopesticides that could be used to control many crop pests. Tetranychus spp. are mites that cause damage to several crops and are primarily controlled by synthetic pesticides. Literature showed that mites can be controlled with essential oils of plants containing eugenol. In this work, we evaluated the bioactivity of basil (Ocimum basicilum) accessions for peanut-spider mites control based on molecular, biochemical and agronomic assays. RNA from four basil accessions, previously chosen by divergence genetic analysis, were used to estimate the expression of eugenol synthase (EGS I) transcripts, by semiquantitative and polymerase chain reaction (qPCR) assays. Chromatography was, thereafter, performed in order to estimate the eugenol concentration. Feeding bioassays were performed using basil leaf extracts in order to estimate oviposition and mortality of spider mites females. Finally, a validation assay was carried out in greenhouse, using peanut plants previously infested with spider mites and weekly sprayed with basil water-extract. One basil accession, OVRS, revealed high phytotoxicity to spider mite females, at 15% water-extract. The mortality rate was 75% and complete inhibition of fecundity was found in BOD assays. In the greenhouse assay, the most severe damage due to mite infestations was found to plant height, number of pods and pod yield, which were reduced to 28, 53 and 52% in non-treated plants (control). Considering that basil is a short-cycle plant, with easy reproduction and management, these results represent an accessible alternative to organic control spider mites in peanut.

Anaesthetic efficacy of eugenol on Flowerhorn (Amphilophus labiatus × Amphilophus trimaculatus )

Anaesthetic efficacy of eugenol was investigated on Flowerhorn (Amphilophus labiatus × Amphilophus trimaculatus). A total of 104 fish with average weights of 12 ± 2.5, 28 ± 5 and 53 ±5.1 g were subjected to 25–200 mg L−1 eugenol and behavioural responses as well as induction and recovery times were recorded. Induction and recovery times were significantly affected by eugenol concentration as well as fish weight (P < 0.05). Generally, 49.9–127.3 s after exposure to 50–200 mg L−1 eugenol, fish reached stage 3 anaesthesia (suitable for general handling). Fish entered stage 4 anaesthesia (suitable for surgery and blood sampling) over 57.3–140.4 s post exposure to such concentrations. Recovery time was 91.7–312 s in all weight classes for all eugenol concentrations. Mortality (23%) was only observed in 12-g fish when were subjected to 200 mg L−1 eugenol. This study showed the behavioural response of Flowerhorn to anaesthesia and eugenol efficacy as an anaesthetic in this important ornamental species. The general quadratic equation revealed that concentrations of eugenol and fish size along with their interactive effects have significantly contributed to the model, with concentration recording the highest beta value in all models (β = −0.809, −0.818 and −0.909, P = 0.000). According to the results, minimum eugenol concentration to induce anaesthesia in less than 3 min was 50 mg L−1.

Eugenol como anestésico para el manejo de juveniles de Pavón (Cichla orinocensis)

Con el objeto de establecer una concentración anestésica de eugenol óptima para una adecuada manipulación de juveniles de Pavón (Cichla orinocensis), 24 juveniles (57,65 ± 43 g y 16.44 ± 1,17 cm de longitud estándar) provenientes de la estación Piscícola Experimental Casa Piedra de la Fundación Orinoquia de Puerto Carreño, Vichada, Colombia, fueron sometidos a diferentes concentraciones de eugenol (30, 40 y 50 mg/L) y un grupo control. Se presentaron diferencias estadísticamente significativas entre los tratamientos tanto para los tiempos de inducción como de recuperación con las concentraciones de 20, 30 y 50 mg/L (p&lt;0,05), siendo el tratamiento de 20 mg/L el que presento el mayor tiempo de inducción (133±63,21 segundos) y el tratamiento de 50 mg/L presento el menor tiempo de inducción (46±17,51 segundos), los tiempos de recuperación del experimento aumentaron conforme aumentaban las concentraciones anestésicas empleadas, se observaron diferencias significativas (p&lt;0,05) entre los tiempos de recuperación de cada tratamiento. La concentración anestésica de eugenol recomendada para juveniles de pavón (C. orinocensis) obtenida en este trabajo es de 35 mg/L.

Acute toxicity and anaesthetic effect of clove oil and eugenol on Siamese fighting fish, Betta splendens

With brilliant colouration and long, flowing fins, the Siamese fighting fish (Betta splendens) is one of the most popular species of freshwater aquarium fish. In the ornamental Siamese fighting fish business, stress is one of the major causes of fish injury, including collapse of the fins. This problem could be solved by using anaesthetic treatment. Clove oil and eugenol were investigated for acute toxicity, which was determined using an aqueous dilution method at concentrations ranging from 0 to 35 mg L−1. Based on a criterion of fish transportation within 2 days, induction times of anaesthesia, fish behavioural responses and mortality, and recovery times were monitored and recorded over a 48-h period. The 48-h LC50 of clove oil and eugenol was 30.63 [with a 95 % confidence interval (CI) of 29.23–32.10 mg L−1] and 29.95 mg L−1 (with a 95 % CI of 28.50–31.48 mg L−1), respectively. Concentrations of 10 and 15 mg L−1 clove oil over a 48-h period induced a sedative effect, resulting in partial loss of reactivity and mobility while maintaining equilibrium. At these concentrations, the fish could recover behaviourally within 3–5 min. Recovery times decreased with lower doses and shorter exposure times. The higher the concentration of either clove oil or eugenol used, the lower the concentrations of total ammonia and un-ionized ammonia that were detected. This study revealed that clove oil and eugenol are highly effective anaesthetic agents as a transportation mixture for Siamese fighting fish.

Eugenol in combination with lactic acid bacteria attenuates Listeria monocytogenes virulence in vitro and in invertebrate model Galleria mellonella

Listeria monocytogenes is a human enteric pathogen that causes severe foodborne illness in high-risk populations. Crossing the intestinal barrier is the first critical step for Listeria monocytogenes infection. Therefore, reducing L. monocytogenes colonization and invasion of intestinal epithelium and production of virulence factors could potentially control listeriosis in humans. This study investigated the efficacy of sub-inhibitory concentration (SIC) of the plant-derived antimicrobial eugenol, either alone, or in combination with five lactic acid bacteria (LAB), namely Bifidobacterium bifidum (NRRL-B41410), Lactobacillus reuteri (B-14172), Lactobacillus fermentum (B-1840), Lactobacillus plantarum (B-4496) and Lactococcus lactis subspecies lactis (B-633) in reducing Listeria monocytogenes adhesion to and invasion of human intestinal epithelial cells (Caco-2). Additionally, the effect of the aforementioned treatments on Listeria monocytogenes listeriolysin production, epithelial E-cadherin binding and expression of virulence genes was investigated. Moreover, the in vivo efficacy of eugenol-LAB treatments in reducing Listeria monocytogenes virulence in the invertebrate model Galleria mellonella was studied. Eugenol and LAB, either alone or in combination, significantly reduced Listeria monocytogenes adhesion to and invasion of intestinal cells (P < 0.05). Moreover, eugenol-LAB treatments decreased Listeria monocytogenes haemolysin production, E-cadherin binding and virulence gene expression (P < 0.05). In addition, the eugenol-LAB treatments significantly enhanced the survival rates of G. mellonella infected with lethal doses of Listeria monocytogenes (P < 0.05). The results highlight the antilisterial effect of eugenol either alone or in combination with LAB, and justify further investigations in a mammalian model.

Effect of 4-Allyl-1-hydroxy-2-methoxybenzene (Eugenol) on Inflammatory and Apoptosis Processes in Dental Pulp Fibroblasts.

Eugenol (mixed with zinc oxide powder) is widely used as direct capping material during pulp therapy in primary teeth. The aim of the present study was to evaluate the effect of eugenol on diverse genes involved in inflammatory and cell apoptosis processes. The regulatory effect of eugenol on the expression of inflammation and apoptotic genes was evaluated in dental pulp fibroblasts from extracted third molars, cultured under concentration of eugenol of 13 μM. Eugenol allowed the expression of inflammatory and apoptotic genes when compared with positive and negative controls. Eugenol is a proinflammatory agent when it is in direct contact with healthy tissues and behaves as an anti-inflammatory agent in tissues undergoing inflammatory/apoptotic processes, as in cases of pulp inflammation in primary teeth. These findings are relevant for dentistry, when considering the application of safer pulp treatments to grossly carious children's teeth.

Adaptação e adaptação cruzada de Listeria monocytogenes aos compostos eugenol e carvacrol

RESUMOA evolução de certos microrganismos permite sua rápida adaptação aos ambientes em constante mudança, desenvolvendo assim, tolerância ou resistência ao aumento de determinados estresses. O uso de compostos bioativos provenientes da flora nativa tem sido apontado como uma possível solução para os problemas de controle da resistência e proliferação bacteriana. Este trabalho visou verificar a adaptação e adaptação cruzada de L. monocytogenes, frente aos compostos fenólicos eugenol e carvacrol. A concentração mínima inibitória (CMI) dos compostos fenólicos foi determinada pela técnica de microdiluição em placas de 96 cavidades, em caldo TSB + 0,5% de Tween 80. As concentrações finais (%) obtidas foram: 0,06; 0,12; 0,24; 0,49; 0,98; 1,95; 3,9; 6,25; 12,5; 25; 50. A suspensão bacteriana padronizada foi inoculada nas cavidades das placas, as quais foram incubadas a 37°C por 24 horas com posterior leitura da absorbância a 620 nm e determinação da CMI. A adaptação das células de L. monocytogenes ao eugenol e carvacrol foi realizada com o cultivo das células em TSB + 0,06% de eugenol ou carvacrol à 37°C por 2 horas. A cultura foi então centrifugada e as células ressuspendidas e padronizadas em TSB. A seguir, realizou-se novamente a técnica de microdiluição em caldo. Os resultados obtidos demonstraram que L. monocytogenes apresentou adaptação e adaptação cruzada frente ao carvacrol e eugenol. A CMI do eugenol e carvacrol foi de 24%. A pré-exposição de L. monocutogenes a concentração sub-letal de 0,06% de carvacrol ou de eugenol aumentou sua resistência. A pré-exposição ao carvacrol promoveu a adaptação de L.monocytogenes a ele aumentando a CMI para 12,5%. Já para o eugenol a CMI passou para 25%. Quando submetidas à concentração sub-letal de eugenol, este promoveu a adaptação das células tanto ao carvacrol quanto ao eugenol, sendo a CMI de 12,5%. Os resultados obtidos demonstraram que L. monocytogenes apresentou adaptação e adaptação cruzada ao carvacrol e eugenol. O presente trabalho sugere estudos futuros ainda mais abrangentes quanto à potencialidade antimicrobiana destes compostos.