Origanum Vulgare L. Essential Oil Research Articles

Phytochemical Characterization and Biological Evaluation of Origanum vulgare L. Essential Oil Formulated as Polymeric Micelles Drug Delivery Systems.

This study presents phytochemical characterization and biological evaluation of Origanum vulgare L. essential oil (OEO) formulated as polymeric micelles drug delivery systems as a possible non-invasive approach for the management of skin tags. GC-MS analysis of Romanian OEO revealed the identification and quantification of 43 volatile compounds (thymol and carvacrol being the main ones). The antioxidant activity was shown by four consecrated methods: CUPRAC, ABTS, ORAC and DPPH. OEO was incorporated by micellar solubilization into a binary hydrogel based on a Pluronic F 127/L 31 block-copolymers mixture. The pH, consistency, spreadability, particle size, polydispersity index and zeta potential of the OEO-loaded poloxamer-based binary hydrogel (OEO-PbH) were investigated. OEO-PbH was skin compatible in terms of pH and exhibited adequate spreadability and consistency. The minimal inhibitory concentrations of the tested OEO were similar to those obtained for the formulation, lower (2.5 µg/mL) for yeast and higher (40-80 µg/mL) for Gram-negative bacilli. As keratinocytes are among main components of skin tags, an in vitro evaluation was conducted in order to see the effect of the formulation against HaCaT human keratinocytes. OEO-PbH decreased HaCaT cells migration and proliferation and elicited a cytotoxic and pro-apoptotic effect in a dose- and time-dependent manner. No harmful effect on the viability of dendritic cells (DCs) was detected following the incubation with different concentrations (0-200 µg/mL) of the 5% formulation. Treatment in inflammatory DCs (+LPS) indicated a decrease in cytokine production of IL-6, TNF-α and IL-23 but no significant effect on IL-10 in any of the tested concentrations.

Stress tolerance and transcriptomic response analysis of Yersinia enterocolitica adapted to Origanum vulgare L. essential oil

The adaptability of foodborne pathogens to sublethal concentrations of antimicrobials including essential oils poses a great threat to food safety. The aim of this study was to evaluate the effect of pre-exposure of Origanum vulgare L. essential oil (OVEO) on the tolerance of Yersinia enterocolitica and explore its adaptive response mechanism by the RNA-Seq. Our data showed that the OVEO induced the direct-tolerance to OVEO and the cross-tolerance to NaCl, KCl and ROEO. In total, 300 DEGs after sublethal OVEO adaption were identified, including 145 upregulated and 155 downregulated. Firstly, OVEO stress could cause proton motive force (PMF) dissipation, Y. enterocolitica activated the phage shock protein response (3.3–3.7 log2(FC)) and reduced unnecessary energy consumption such as mobility, flagellum formation and quorum sensing to maintain the PMF balance and ensure the normal physiological function. Secondly, genes associated with synthesis and transport of glycerol-3-phosphate were upregulated 1.7–2.2 log2(FC) to repair the structure and function of cell membrane under OVEO stress. Besides, PstSCAB transporter of phosphotransferase system were activated to ensure the energy supply and cell constituents synthesis under OVEO stress. Finally, Y. enterocolitica prevented the cell from oxidization damage by increasing the expression of glutathione peroxidase and amino acid synthesis-associated genes (2.0–3.9 log2(FC)).

Origanum vulgare L. essential oil inhibits virulence patterns of Candida spp. and potentiates the effects of fluconazole and nystatin in vitro

BackgroundRecurrence and resistance of Candida spp. infections is associated with the ability of these microorganisms to present several virulence patterns such as morphogenesis, adhesion, and biofilm formation. In the search for agents with antivirulence activity, essential oils could represent a strategy to act against biofilms and to potentiate antifungal drugs.ObjectiveTo evaluate the antivirulence effect of Origanum vulgare L. essential oil (O-EO) against Candida spp. and to potentiate the effect of fluconazole and nystatin.MethodsThe effect of O-EO was evaluated on ATCC reference strains of C. albicans and non-albicans Candida species. Minimum inhibitory concentration (MIC) was determined through broth microdilution assay. Adhesion to microplates was determined by crystal violet (CV) assay. An adapted scratch assay in 24-well was used to determine the effect of essential oil on biofilms proliferation. Viability of biofilms was evaluated by MTT reduction assay and through a checkerboard assay we determined if O-EO could act synergistically with fluconazole and nystatin.ResultsMIC for C. albicans ATCC-90029 and ATCC-10231 was 0.01 mg/L and 0.97 mg/L, respectively. For non-albicans Candida strains MIC values were 2.6 mg/L for C. dubliniensis ATCC-CD36 and 5.3 mg/L for C. krusei ATCC-6258. By using these concentrations, O-EO inhibited morphogenesis, adhesion, and proliferation at least by 50% for the strains assayed. In formed biofilms O-EO decreased viability in ATCC 90029 and ATCC 10231 strains (IC50 7.4 and 2.8 mg/L respectively). Finally, we show that O-EO interacted synergistically with fluconazole and nystatin.ConclusionsThis study demonstrate that O-EO could be considered to improve the antifungal treatment against Candida spp.

Characterization and antimicrobial efficacy of active biocomposite containing polylactic acid, oregano essential oil and nisin for pork storage

Traditional packaging made from non-renewable compounds such as petroleum has a negative impact on the environment, which has led to a growing body of research on biodegradable packaging. This paper details the characterization of a biocomposite which was made from cassava bran, coffee husk, and water (BCCW). After this, a layer of polylactic acid (PLA) was added, mixed with nisaplin 1000UI, and 8, 10, 12% concentrations of oregano (Origanum vulgare L) essential oil (OVEO) in order to create an active biocomposite (AB) which could be used as an antimicrobial material in the packaging of pork. In vitro inhibitory effects were evaluated against Listeria monocytogenes, Escherichia coli and Salmonella typhimurium. After obtaining the active biocomposite, the characterization was performed by means of Infrared Spectroscopy (FT-IR), Water Vapor Permeability (WVP), a Mechanical Property analysis, Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM). Using the concentration with the highest inhibition against pathogenic bacteria, antimicrobial tests were carried out after the application of the AB in pork meat for 0, 1, 3, 5, and 10 days. Inhibition tests against pathogenic bacteria showed that nisin had a greater effect on Gram positive bacteria, while OVEO had an effect on both Gram positive and Gram negative bacteria. FT-IR analysis allowed for the characterization of the molecular interactions of OVEO and nisin in the matrix compounds of the different biocomposites by identifying and interpreting their respective vibration bands. According to the statistical analysis, the different concentrations of the biocomposites affect WVP (p <0.05). BCCW showed the highest permeability to water vapor, whereas the other treatments did not show significant differences. The mechanical properties test of the AB showed that the different treatments had a significant effect (p <0.05) on the maximum flexural strength and flexural modulus. These values decreased with the application of the PLA layer, the concentrations of the biocomposites did not have a significant maximum deformation effect (p> 0.05). The DSC test on the ABs showed two melting peaks and an increase in the glass transition temperature (Tg) of the PLA, a finding that indicates greater thermal stability in the ABs. SEM images revealed that the nisaplin and OVEO particles were uniformly distributed in the PLA polymer matrix on the surface of the ABs. The ABs showed a significant reduction in Listeria monocytogenes in pork as of day 3 and in the other pathogens as of the 10th day. The biocomposite containing OVEO and nisaplin, showed good potential to be used to food packaging.

A Recent Insight Regarding the Phytochemistry and Bioactivity of Origanum vulgare L. Essential Oil.

Origanum vulgare L. is a widely used aromatic plant, especially due to its content in essential oil, mainly rich in carvacrol and thymol. The ethnopharmacological uses of Origanum vulgare L. essential oil (OEO) comprise digestive, respiratory, or dermatological disorders. The review focuses on the increasing number of recent studies investigating several biological activities of OEO. The bioactivities are in tight relation to the phytochemical profile of the essential oil, and also depend on taxonomic, climatic, and geographical characteristics of the plant material. The antibacterial, antifungal, antiparasitic, antioxidant, anti-inflammatory, antitumor, skin disorders beneficial effects, next to antihyperglycemic and anti-Alzheimer activities were reported and confirmed in multiple studies. Moreover, recent studies indicate a positive impact on skin disorders of OEO formulated as nanocarrier systems in order to improve its bioavailability and, thus, enhancing its therapeutic benefits. The review brings an up to date regarding the phytochemistry and bioactivity of Origanum vulgare L. essential oil, underlining also the most successful pharmaceutical formulation used for skin disorders.

Effect of Origanum vulgare essential oil on biofilm formation and motility capacity of Pseudomonas fluorescens strains isolated from discoloured Mozzarella cheese.

The study was focused on Pseudomonas fluorescens strains isolated from Mozzarella cheese, with the aim of evaluating the effects of Origanum vulgare L. essential oil (OEO) on the biofilm formation and eradication, as well as on the motility and blue pigment production at 10°C. Microdilution method was used to determine the minimum inhibitory and bactericidal concentration of the OEO, which ranged between 10 and 40μlml-1 . In vitro studies demonstrated that a sublethal concentration of OEO influenced not only P. fluorescens growth and motility but also the capability to form biofilm and, in a lower degree, the biofilm eradication at 10°C. Analysis by confocal microscopy revealed a dramatic reduction in biofilm formation and thickness, with scattered damage or death of cells, stained by propidium iodide. In addition, a concentration of 5μlml-1 of OEO affected the motility of the cells and, in particular, their ability to swim. However, the essential oil did not inhibit the blue pigment production by any of the tested strains. The present findings suggest that oregano essential oil inhibits the biofilm formation of P. fluorescens strains and alters their motility. Moreover, in the preformed biofilm, OEO contributes to the detachment of the cells, deteriorating the architecture of the biofilm and reducing its thickness. The O. vulgare L. essential oil was revealed as a promising agent against biofilm formation and for its detaching; these results suggest that oregano EO could be used in the dairy food industry to control biofilm formation, as an alternative, or in combination with conventional sanitizers.

Changes in thermo-tolerance and survival under simulated gastrointestinal conditions of Salmonella Enteritidis PT4 and Salmonella Typhimurium PT4 in chicken breast meat after exposure to sequential stresses

This study assessed changes in thermo-tolerance and capability to survive to simulated gastrointestinal conditions of Salmonella Enteritidis PT4 and Salmonella Typhimurium PT4 inoculated in chicken breast meat following exposure to stresses (cold, acid and osmotic) commonly imposed during food processing. The effects of the stress imposed by exposure to oregano (Origanum vulgare L.) essential oil (OVEO) on thermo-tolerance were also assessed. After exposure to cold stress (5°C for 5h) in chicken breast meat the test strains were sequentially exposed to the different stressing substances (lactic acid, NaCl or OVEO) at sub-lethal amounts, which were defined considering previously determined minimum inhibitory concentrations, and finally to thermal treatment (55°C for 30min). Resistant cells from distinct sequential treatments were exposed to simulated gastrointestinal conditions. The exposure to cold stress did not result in increased tolerance to acid stress (lactic acid: 5 and 2.5μL/g) for both strains. Cells of S. Typhimurium PT4 and S. Enteritidis PT4 previously exposed to acid stress showed higher (p<0.05) tolerance to osmotic stress (NaCl: 75 or 37.5mg/g) compared to non-acid-exposed cells. Exposure to osmotic stress without previous exposure to acid stress caused a salt-concentration dependent decrease in counts for both strains. Exposure to OVEO (1.25 and 0.62μL/g) decreased the acid and osmotic tolerance of both S. Enteritidis PT4 and S. Typhimurium PT4. Sequential exposure to acid and osmotic stress conditions after cold exposure increased (p<0.05) the thermo-tolerance in both strains. The cells that survived the sequential stress exposure (resistant) showed higher tolerance (p<0.05) to acidic conditions during continuous exposure (182min) to simulated gastrointestinal conditions. Resistant cells of S. Enteritidis PT4 and S. Typhimurium PT4 showed higher survival rates (p<0.05) than control cells at the end of the in vitro digestion. These results show that sequential exposure to multiple sub-lethal stresses may increase the thermo-tolerance and enhance the survival under gastrointestinal conditions of S. Enteritidis PT4 and S. Typhimurium PT4.

Development of flexible bactericidal films based on poly(lactic acid) and essential oil and its effectiveness to reduce microbial growth of refrigerated rainbow trout

The main shortcoming of poly(lactic acid) (PLA) for food packaging applications is its brittleness. The aim of this work was to evaluate the potential use of Origanum vulgare L. essential oil (OEO) in PLA-based matrices to obtain developed bio-based films with enhanced mechanical properties as well as antimicrobial performance. The PLA-essential oil composite films were more flexible than neat PLA films; so that up to 6-fold increase in the elongation-at-break values (2.82–16.78%) were acquired when 0.5% (w/w) oil was added to the polymer matrix. The addition of essential oil decreased the PLA glass transition temperature (Tg), as the result of the polymer plasticization, and led to modification of the tensile behavior. AFM results confirmed that the PLA surface microstructure was drastically influenced in terms of roughness parameters (Ra and Rq) when OEO was added. The films’ antimicrobial activities were induced by incorporating essential oil, which were more effective against the bacteria in direct contact method than a vapor phase. However, in both of test methods, Staphylococcus aureus was the most sensitive bacterium to OEO-containing films, while Escherichia coli was the most resistant. Then, efficacy of bioactive film included with 1.5% (w/w) essential oil to reduce microbial growth of rainbow trout during chilled storage was evaluated; the results indicated that antimicrobial PLA film was effective against all the microorganisms tested in this study. These results suggest that the developed PLA films with active substance could be used in designing antimicrobial packaging materials.

Development of bioactive fish gelatin/chitosan nanoparticles composite films with antimicrobial properties

The objective of this work was to develop active bio-based nanocomposite films from fish gelatin (FG) and chitosan nanoparticles (CSNPs) incorporated with Origanum vulgare L. essential oil (OEO). CSNPs were obtained by ionic gelation of chitosan with sodium tripolyphosphate, which presented a spherical morphology with size range of 40–80nm. Remarkable differences in the surface morphology were observed between the control and bioactive nanocomposite films as revealed by SEM and AFM images. FTIR results confirmed that an interaction between polymer matrix and essential oil had occurred, as shown by an increase in the amplitude of peaks at wavenumbers 1242cm−1 and 1451cm−1. Meanwhile, XRD peaks of OEO-containing films were more intense, indicating that the introduction of essential oil into the film matrix induces an increase in crystallinity. TGA analysis demonstrated that the addition of OEO had no impact on thermal stability of the films. Inclusion of OEO in the film matrix resulted in less resistant and more flexible films, with a decrease in water vapor permeability (WVP). The FG/CSNPs bioactive films exhibited distinctive antimicrobial activity against four test food pathogens, namely Staphylococcus aureus, Listeria monocytogenes, Salmonella enteritidis and Escherichia coli.

Habituation of enterotoxigenic &lt;italic&gt;Staphylococcus aureus&lt;/italic&gt; to &lt;italic&gt;Origanum vulgare&lt;/italic&gt; L. essential oil does not induce direct-tolerance and cross-tolerance to salts and organic acids

Enterotoxigenic Staphylococcus aureus strains that were isolated from foods were investigated for their ability to develop direct-tolerance and cross-tolerance to sodium chloride (NaCl), potassium chloride (KCl), lactic acid (LA) and acetic acid (AA) after habituation in sublethal amounts (1/2 of the minimum inhibitory concentration - 1/2 MIC and 1/4 of the minimum inhibitory concentration - 1/4 MIC) of Origanum vulgare L. essential oil (OVEO). The habituation of S. aureus to 1/2 MIC and 1/4 MIC of OVEO did not induce direct-tolerance or cross-tolerance in the tested strains, as assessed by modulation of MIC values. Otherwise, exposing the strains to OVEO at sublethal concentrations maintained or increased the sensitivity of the cells to the tested stressing agents because the MIC values of OVEO, NaCl, KCl, LA and AA against the cells that were previously habituated to OVEO remained the same or decreased when compared with non-habituated cells. These data indicate that OVEO does not have an inductive effect on the acquisition of direct-tolerance or cross-tolerance in the tested enterotoxigenic strains of S. aureus to antimicrobial agents that are typically used in food preservation.

Bio-based composite edible films containing Origanumvulgare L. essential oil

Biocomposite films based on fish gelatin and chitosan containing Origanumvulgare L. essential oil (OEO) at 0.4, 0.8, and 1.2% (w/v) were prepared by a solvent casting method and their physicochemical and antimicrobial properties were examined. The results showed that the incorporation of OEO caused a significant decrease (p<0.05) in tensile strength (TS) and elastic modulus (EM), although no significant change was observed in elongation-at-break (EAB). Water vapor permeability (WVP) and solubility of films containing OEO increased as the amount of oil increased (p<0.05). Oregano essential oil-loaded films displayed superior barrier capability to ultraviolet light. Fourier transforms infrared (FTIR) spectra indicated that the interaction between polymer matrix and essential oil was occurred. The properties of the films were related with their microstructure, which was observed by scanning electron microscopy (SEM). Atomic force microscopy (AFM) images showed that the surface roughness of the films was influenced by the inclusion of oil. OEO-incorporated films also exhibited higher antimicrobial activity against the gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes), and lower for gram-negative bacteria (Salmonella enteritidis and Escherichia coli). This study showed that OEO has the potential to prepare active edible films.

Tolerance response of multidrug-resistant Salmonella enterica strains to habituation to Origanum vulgare L. essential oil.

Multidrug-resistant Salmonella enterica isolates from human outbreaks or from poultry origin were investigated for their ability to develop direct-tolerance or cross-tolerance to sodium chloride, potassium chloride, lactic acid, acetic acid, and ciprofloxacin after habituation in subinhibitory amounts ( of the minimum inhibitory concentration – (MIC) and of the minimum inhibitory concentration – MIC) of Origanum vulgare L. essential oil (OVEO) at different time intervals. The habituation of S. enterica to OVEO did not induce direct-tolerance or cross-tolerance in the tested strains, as assessed by the modulation of MIC values. However, cells habituated to OVEO maintained or increased susceptibility to the tested antimicrobials agents, with up to fourfold double dilution decrease from previously determined MIC values. This study reports for the first time the non-inductive effect of OVEO on the acquisition of direct-tolerance or cross-tolerance in multidrug-resistant S. enterica strains to antimicrobial agents that are largely used in food preservation, as well as to CIP, the therapeutic drug of salmonellosis.

Assessment of tolerance induction by Origanum vulgare L. essential oil or carvacrol in Pseudomonas aeruginosa cultivated in a meat-based broth and in a meat model.

This study assessed the efficacy of Origanum vulgare L. essential oil (OVEO) and carvacrol in inhibiting the growth of Pseudomonas aeruginosa ATCC 9027, as well as the development of direct tolerance and cross-tolerance when this bacterium was challenged with sublethal amounts of these substances in a meat-based broth and in a meat model. OVEO and carvacrol at their minimum inhibitory concentrations (MICs), 1/2 MIC and 1/4 MIC decreased the viable cell counts of P. aeruginosa in meat-based broth. Direct tolerance or cross-tolerance was not induced after exposure of the assayed bacterial strain to sublethal amounts of OVEO or carvacrol in meat-based broth and in an artificially contaminated ground beef. Bacterial cells progressively subcultured in meat-based broth with increasing amounts of the tested substances survived up to the MIC of OVEO and to 1/2 MIC of carvacrol. The results reveal a lack of induction of tolerance in P. aeruginosa by exposure to OVEO or carvacrol in meat-based broth and in a meat model.

Lack of induction of direct protection or cross-protection in Staphylococcus aureus by sublethal concentrations of Origanum vulgare L. essential oil and carvacrol in a meat-based medium

The capacity of Origanum vulgare L. essential oil (OVEO) and its majority compound, carvacrol (CAR), to induce direct tolerance and cross-tolerance in Staphylococcus aureus against high temperature (45 °C), lactic acid (pH 5.2) and NaCl (10 g/100 mL) was assessed. Overnight exposure of S. aureus to sublethal concentrations (1/2 MIC, 1/4 MIC) of either OVEO or CAR in meat broth revealed no induction of direct protection. S. aureus cells pre-adapted to OVEO or CAR showed no induction of cross-protection to high temperature, lactic acid or NaCl. Cells subjected to 24 h cycles of adaptation in increasing amounts (1/2 MIC to 2 × MIC) of OVEO or CAR showed no increase in direct tolerance. These results revealed a lack of induction of direct protection or cross-protection in S. aureus exposed to sublethal amounts of OVEO or CAR in meat-based broth, as determined by monitoring cell survival and growth behavior.

Exposure of Listeria monocytogenes to sublethal amounts of Origanum vulgare L. essential oil or carvacrol in a food-based medium does not induce direct or cross protection

In this study, the effects of Origanum vulgare L. essential oil (OVEO) and carvacrol (CAR) on the growth and survival of Listeria monocytogenes ATCC 7644 were evaluated. The induction of direct protection against OVEO and CAR and of cross protection against various stresses (high temperature 45°C; lactic acid, pH 5.2; NaCl 10g/100mL) after exposure to sublethal amounts of OVEO and CAR was also evaluated. Both OVEO and CAR decreased the cell viability of L. monocytogenes in meat broth over 120min of exposure at all assayed concentrations (MIC, 1/2 MIC and 1/4 MIC). The overnight exposure of L. monocytogenes to sublethal amounts of OVEO or CAR did not induce direct protection or cross protection against high temperature, lactic acid or NaCl. Cells that were subcultured (24h cycles) in meat broth containing progressively increasing amounts of the antimicrobials were able to survive exposure to up to 2×MIC (two-fold increase) of OVEO and up to the MIC (one-fold increase in MIC) of CAR, suggesting that there were only minor changes in the antimicrobial susceptibility to these substances. Overall, these data indicate that OVEO and CAR have little effect on the acquisition of direct resistance or cross resistance by L. monocytogenes.