Origanum Vulgare Essential Oil Research Articles

Technical-economic analisys of the solvent-method optimization of Origanum vulgare essential oil extraction based on technical and quality criteria

The aim of the present research was oriented to study the effect of solvent polarity, solute–solvent ratio, selection of the solvent method and particle size on the performance of the Origanum vulgare extraction, its parameters in reference to quality physicochemical criteria and its technoeconomic feasibility. A completely randomized experimental design with A $$\times$$ B factorial arrangement was used, with the purpose of establishing adequate data processing that will serve as a basis for diagrams that interpret the kinetics of an extraction process at defined conditions (pressure and temperature), in intimate relation to the polarity of the solvent. The application of technical standards in the characterization of plant matter and final product has been considered, physically and chemically analyzing its main properties (humidity 10.7453% wet basis, ethereal extract 1.833%, refractive index 1.4774–1.4790, acidity index 0.4632–0.7628% and density 0.9169–0.9396). The described actions affirm the detailed analysis about the extraction process and the operative variables that affect the phenomenon, focused on the generation of experimental mathematical monograms and models that reflect the characteristics of obtaining the essential oil of O. vulgare, which contributes to the reduction of the production conflicts associated with the extraction (the type of solvent, particle size, solute–solvent ratio, environmental pollution, etc.) of essential oils, with lower costs, best strategies and higher yields. Two kinetic models were successfully used to describe the phenomenon produced by hydrodistillation in O. vulgare essential oil.

Use of Origanum vulgare Essential Oil as an Antibacterial Additive in the Preservation of Minced Meat

The essential oil extracted by hydrodistillation from the aerial parts of Origanum vulgare L. harvested in the region of Skikda (North-East-Algeria) gave an excellent oil yield (2.8%). Its analysis by Gas Chromatography–Mass Spectrometry (GC/MS) identified 98.10% of its constituents. The major components are: carvacrol (47.6%), thymol (16.6%), p-cymene (13.5%) and γ-terpinene (11.2%).
 The aim of this study was to the preservative effect of Origanum vulgare essential oil applied to a very low concentration of 0.025% (minimum inhibitory concentration (MIC)), of a sensitive food of essential nutritional value, of great consumption and easily perishable “minced meat”, stored at different times, namely: T0 = 0 min, T1 = 40 min, T2 = 24 h, and T3 = 48 h. By studying its microbiological quality by determining the rate of reduction of the total aerobic mesophilic microflora and of Staphylococcus aureus. The addition of Origanum vulgare essential oil to minced meat allowed a highly significant reduction of 0.01<p<0.1 in total aerobic mesophilic microflora reduction rate and very highly significant (p≤0.01) for Staphylococcus aureus, and markedly increase the shelf life. This allows us to propose the use of this essential oil as a source of natural preservative substances.

Organic management vs. conventional management influence the antimicrobial activity of essential oils of Origanum vulgare L

The objective this stud was to evaluate the antimicrobial activity of essential oils (organic vs. conventional) of Origanum vulgare L. in the action against Candida albicans, Escherichia coli and Staphylococcus aureus. The inoculation of rhizobacteria (environmental (ME) and Bacillus subtilis) potentiated the antimicrobial action. The essential oils of Traditional (organic) cultivation presented antibacterial action and antifungal, while the essential oil of conventional cultivation (NPK) showed no any antibacterial or antifungal activity. It was concluded that the formulation of vermicomposting and the use of rhizobacteria are potential technologies and tools for family farmers and traditional community in the cultivation of orégano.

Origanum vulgare essential oil: antibacterial activities and synergistic effect with polymyxin B against multidrug-resistant Acinetobacter baumannii.

Antimicrobial resistance is increasing around the world and the search for effective treatment options, such as new antibiotics and combination therapy is urgently needed. The present study evaluates oregano essential oil (OEO) antibacterial activities against reference and multidrug-resistant clinical isolates of Acinetobacter baumannii (Ab-MDR). Additionally, the combination of the OEO and polymyxin B was evaluated against Ab-MDR. Ten clinical isolates were characterized at the species level through multiplex polymerase chain reaction (PCR) for the gyrB and blaOXA-51-like genes. The isolates were resistant to at least four different classes of antimicrobial agents, namely, aminoglycosides, cephems, carbapenems, and fluoroquinolones. All isolates were metallo-β-lactamase (MβL) and carbapenemase producers. The major component of OEO was found to be carvacrol (71.0%) followed by β-caryophyllene (4.0%), γ-terpinene (4.5%), p-cymene (3,5%), and thymol (3.0%). OEO showed antibacterial effect against all Ab-MDR tested, with minimum inhibitory concentrations (MIC) ranging from 1.75 to 3.50mgmL-1. Flow cytometry demonstrated that the OEO causes destabilization and rupture of the bacterial cell membrane resulting in apoptosis of A. baumannii cells (p < 0.05). Synergic interaction between OEO and polymyxin B (FICI: 0.18 to 0.37) was observed, using a checkerboard assay. When combined, OEO presented until 16-fold reduction of the polymyxin B MIC. The results presented here indicate that the OEO used alone or in combination with polymyxin B in the treatment of Ab-MDR infections is promising. To the best of our knowledge, this is the first report of OEO and polymyxin B association against Ab-MDR clinical isolates.

Origanum vulgare Essential Oil vs. a Commercial Mixture of Essential Oils: In Vitro Effectiveness on Salmonella spp. from Poultry and Swine Intensive Livestock.

Salmonella spp. represent a public health concern for humans and animals due to the increase of antibiotic resistances. In this scenario, the use of essential oils (EOs) could be a valid tool against Salmonella contamination of meat. This work compares the in vitro effectiveness of an Italian mixture of feed additives based on EOs (GR-OLI) with EO of Origanum vulgare L., recently admitted by European Food Safety Authority (EFSA) for animal use. Twenty-nine Salmonella serotypes isolated from poultry and pig farms were used to assess GR-OLI and O. vulgare EO antimicrobial propeties. O. vulgare EO was active on the disaggregation of mature biofilm, while GR-OLI was capable of inhibiting biofilm formation and disaggregating preformed biofilm. Furthermore, GR-OLI inhibited bacterial adhesion to Caco-2 cells in a dose-dependent manner. Both products showed inhibition of bacterial growth at all time points tested. Finally, the synergistic action of GR-OLI with commonly used antibiotics against resistant strains was investigated. In conclusion, the mixture could be used both to reduce the meat contamination of Salmonella spp. before slaughter, and in synergy with low doses of ciprofloxacin against resistant strains. Although EOs as feed additives are already used in animal husbandry, no scientific study has ever highlighted their real antimicrobial potential.

Antioxidant and Antibacterial Capacities of Origanum vulgare L. Essential Oil from the Arid Andean Region of Chile and its Chemical Characterization by GC-MS

This study aimed to characterize the in vitro antioxidant and antibacterial properties of oregano (Origanum vulgare) essential oil, as well as its chemical composition. To our best knowledge, there are few studies on oregano grown in the arid Andes region, but none on the metabolites produced and their bioactivity. This work identified fifty metabolites by Gas Chromatography–Mass Spectrometry (GC-MS)—monoterpene hydrocarbons, oxygenated monoterpenes, phenolic monoterpenes, sesquiterpene hydrocarbons, and oxygenated sesquiterpenes—present in the essential oil of oregano collected in the Atacama Desert. The main components of essential oregano oil were thymol (15.9%), Z-sabinene hydrate (13.4%), γ-terpinene (10.6%), p-cymene (8.6%), linalyl acetate (7.2%), sabinene (6.5%), and carvacrol methyl ether (5.6%). The antibacterial tests showed that the pathogenic bacteria Staphylococcus aureus and Salmonella enterica and the phytopathogenic bacteria Erwinia rhapontici and Xanthomonas campestris were the most susceptible to oregano oil, with the lowest concentrations of oil necessary to inhibit their bacterial growth. Moreover, oregano oil showed antibacterial activity against bacteria associated with food poisoning. In conclusion, O. vulgare from the arid Andean region possesses an important antibacterial activity with a high potential in the food industry and agriculture.

Improving the Quality of Turkey Meat via Storage Temperature, Packaging Atmosphere, and Oregano (Origanum vulgare) Essential Oil Addition

The provision of plentiful good-quality food is a primary issue in the modern world. This work was planned to study the influence of packaging atmosphere and oregano (Origanum vulgare) essential oil addition [(vacuum packaging: T1 or modified atmosphere packaging or T2 (CO2/N2 = 4:6) or T3, T2 with oregano essential oil (T2 + EO)] under various storage temperatures (0, 5, 10, and 15 °C) on the control of survival of Escherichia coli O157:H7 and associated spoilage flora in sliced smoked turkey meat. The pathogen increased by only &lt;1.0 log colony-forming unit (CFU)/g under all packaging and temperature combinations. Moreover, T1, T2, and T3 exerted practically similar inhibitory activity against the pathogen and dominating bacteria, with a relatively low growth of E. coli O157:H7 in sliced smoked turkey during the shelf life under all storage regimes compared to the control. However, the pathogen survival was highest on the sliced smoked turkey under T1, decreasing by only 0.67, 0.74, 0.63, and 1.30 log CFU/g within 37 days if kept at 0, 5, 10, and 15 °C, respectively. Under T2 and the same condition, E. coli O157:H7 in the product declined by only 0.31, 0.50, 0.72, and 1.10 log CFU/g within 37 days of storage, respectively. In the T3 samples, the pathogen was reduced by only 0.33, 0.67, 1.72, and 3.46 log CFU/g through 37 days of storage, respectively. Under T3 were E. coli O157:H7 populations in smoked turkey eliminated (negative by enrichment) under all conditions (after 129, 95, 95, and 43 days maintained at 0, 5, 10, and 15 °C, respectively) compared with other packaging temperature combinations. Thus, T3 contributed to developing ready-to-eat smoked turkey with enhanced product quality and eliminating the pathogen.

Dietary Origanum vulgare essential oil attenuates cypermethrin-induced biochemical changes, oxidative stress, histopathological alterations, apoptosis, and reduces DNA damage in Common carp (Cyprinus carpio)

The study was designed to evaluate the possible protective roles of dietary Origanum vulgare essential oil (OVEO) against cypermethrin (CP)-induced serum biochemical changes and oxidative stress of common carp (Cyprinus carpio). Moreover, histopathological alterations, apoptosis, cell proliferation, and DNA damage in the gills and hepatic tissues were also assessed. Briefly, fish were allotted into six groups with three triplicates whereas a group fed on basal diet and did not exposed to CP and served as control (CTR), two groups were fed on diets supplemented with two levels of OVEO (0.5 % and 1.0 %), a group exposed to sub-lethal concentration of CP (1/10 of 96 h-LC50 = 0.4134 μg/L), and two other groups exposed to the same concentration of CP and fed on diets supplemented with both levels of OVEO (CP + 0.5 % OVEO, and CP + 1.0 % OVEO), respectively, for 30 days. CP induced significant elevation of serum alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), urea, and creatinine levels indicating hepato-renal toxicity (P < 0.05). Besides, there was a significant decrease in serum catalase (CAT) and superoxide dismutase (SOD) activities (P < 0.05). Moreover, CP induced significant histopathologic alterations in gills, anterior kidneys, and hepatic tissues with activation of apoptosis (Caspase-3) and proliferating cell nuclear antigen (PCNA). Comet assay demonstrated significant DNA damage in gills and liver tissues of the CP-exposed group. Interestingly, a significant attenuation of serum ALT, AST, ALP, urea, creatinine, CAT, and SOD levels (P < 0.05) was noticed in CP-exposed fish and concurrently fed diets supplemented with either 0.5 % or 1.0 % OVEO. Moreover, histopathologic alterations and apoptosis were significantly reduced along with a concomitant significant decrease in DNA damage (P < 0.05) which indicated the mitigation of DNA damage. Conclusively, the study showed that OVEO is an effective counteractive treatment against CP-induced damage in exposed common carp and is recommended during the formulation of fish rations.

Comparative Antibacterial Activity and Quality Assessment of Essential Oils from Different Producers Against Oral Pathogens

Abstract The aim of the study is to evaluate antibacterial properties of commercial essential oils (Oregano, Black pepper, Coriander, Cinnamon) against oral pathogens (Streptococcus mutans, Enterococcus faecalis). Nevertheless, we want to asses if the price of the essential oils (EO) which were purchased from 2 different retailers, can influence the quality of essential oil and the antimicrobial effect. Materials and methods: Essential oils from two different Producers (A-high price range, respectively B-low price range) with two opposite price ranges were purchased from local retailers. The inhibitory effect was assessed by disk diffusion. Bacterial inoculums of 0.5 McFarland units (~1.5 x 108 CFU/ml) were prepared from Streptococcus mutans Enterococcus faecalis. Muller-Hinton agar plates were inoculated with bacterial inoculums. Sterile paper disks with the diameter of 6 mm (Bioanalyse Ltd, Turkey) were dispensed on the medium surface. Five μl of essential oils were pipetted on corresponding disks. After 10 minutes (time needed for a proper diffusion of active components), the plates were incubated in normal atmosphere at 37°C. After 24 hours of incubation, the inhibition zone diameters (in millimeters) were read and noted in spreadsheet software, aside the average price in €/ml of essential oil. A cost-efficiency antibacterial activity index was also calculated.Results:With regard to EO from Producer A, the inhibition zone against Enteroccocus ranged from the weakest 14mm(Black pepper), 28mm(Coriander) to the strongest over 40 mm(Oregano and Cinnamon). With regard to volatile essential oils from Producer B, against the Enteroccocus, the smallest inhibition zone was observed for Coriander (10 mm), followed by Black pepper(11 mm); on the opposite side, the strongest inhibition zone presented both Oregano EO and Cinnamon EO (34 mm). Against S. mutans, the weakest inhibition zone showed Black pepper(6 mm), followed by Coriander EO(12 mm) and the strongest inhibition zone had Oregano EO(38 mm) and Cinnamon EO (40 mm). All the EO from the Producer A managed to successfully inhibit S. mutans growth. In both producers, Origanum vulgare EO was the most cost-efficient against E. faecalis (index=0.06 for Producer A and 0.03 for Producer B). In the case of Producer A, against S.mutans the best index was seen at Coriandrum sativum EO (0,05) and the weakest at Cinnamonum zeylanicum (0,14). In the case of Producer B, against E. faecalis, the lowest index was seen at Piper nigrum(0,13). The same pattern was seen against S. mutans, the highest index had Origanum vulgare(0,03) and the lowest Piper nigrum (0,23) Conclusions:Most of essential oils studied from both Producers, had better antibacterial effect against S. mutans compared to E. faecalis.All the EO from the Producer A managed to successfully inhibit S. mutans growth.The high price EO had a better antimicrobial effect compared to the low price EO.The strongest antimicrobial effect against E.faecalis had the high-price Oregano and Cinnamon EO and the weakest antimicrobial effect had low-price Coriander EO. Against S. mutans, the greatest efficacy had all high-price EO, and the lowest had the low-price Black pepper EO.The high price of some EO (Piper nigrum) does not make any difference regarding the antibacterial effect. Lower price EO may be still suitable in regards of antibacterial effect if considering the associated costs, even if the effect does not reach the potency of the higher-price alternatives.

Effects of Origanum vulgare essential oil and its two main components, carvacrol and thymol, on the plant pathogen Botrytis cinerea.

BackgroundBotrytis cinerea causes serious gray mold disease in many plants. This pathogen has developed resistance to many fungicides. Thus, it has become necessary to look for new safe yet effective compounds against B. cinerea.MethodsEssential oils (EOs) from 17 plant species were assayed against B. cinerea, of which Origanum vulgare essential oil (OVEO) showed strong antifungal activity, and accordingly its main components were detected by GC/MS. Further study was conducted on the effects of OVEO, carvacrol and thymol in vitro on mycelium growth and spore germination, mycelium morphology, leakages of cytoplasmic contents, mitochondrial injury and accumulation of reactive oxygen species (ROS) of B. cinerea. The control efficacies of OVEO, carvacrol and thymol on tomato gray mold were evaluated in vivo.ResultsOf all the 17 plant EOs tested, Cinnamomum cassia, Litsea cubeba var. formosana and O. vulgare EOs had the best inhibitory effect on B. cinerea, with 0.5 mg/mL completely inhibiting the mycelium growth of B. cinerea. Twenty-one different compounds of OVEO were identified by gas chromatography–mass spectrometry, and the main chemical components were carvacrol (89.98%), β-caryophyllene (3.34%), thymol (2.39%), α-humulene (1.38%) and 1-methyl-2-propan-2-ylbenzene isopropyl benzene (1.36%). In vitro experiment showed EC50 values of OVEO, carvacrol and thymol were 140.04, 9.09 and 21.32 μg/mL, respectively. Carvacrol and thymol completely inhibited the spore germination of B. cinerea at the concentration of 300 μg/mL while the inhibition rate of OVEO was 80.03%. EC50 of carvacrol and thymol have significantly (P < 0.05) reduced the fresh and dry weight of mycelia. The collapse and damage on B. cinerea mycelia treated with 40 μg/mL of carvacrol and thymol was examined by scanning electron microscope (SEM). Through extracellular conductivity test and fluorescence microscope observation, it was found that carvacrol and thymol led to increase the permeability of target cells, the destruction of mitochondrial membrane and ROS accumulation. In vivo conditions, 1000 μg/mL carvacrol had the best protective and therapeutic effects on tomato gray mold (77.98% and 28.04%, respectively), and the protective effect was significantly higher than that of 400 μg/mL pyrimethanil (43.15%). While the therapeutic and protective effects of 1,000 μg/mL OVEO and thymol were comparable to chemical control.ConclusionsOVEO showed moderate antifungal activity, whereas its main components carvacrol and thymol have great application potential as natural fungicides or lead compounds for commercial fungicides in preventing and controlling plant diseases caused by B. cinerea.

New α-glucosidase inhibitors from a chemically engineered essential oil of Origanum vulgare L.

Chemical transformation of plant extracts can lead to the generation of semisynthetic derivatives that display biomolecular properties that were absent in the natural components of the starting material. The objective of this work was to produce new α-glucosidase inhibitors through O-sulfonylation of essential oils. Thirteen essential oils were chemically diversified with benzenesulfonyl chloride and screened for their in vitro α-glucosidase inhibitory effect. The chemically engineered Origanum vulgare L. (Lamiaceae) essential oil showed the highest inhibition percentage of the series. Using chromatography, nuclear magnetic resonance, and mass spectrometry, the benzenesulfonyl esters of thymol and carvacrol were identified as responsible compounds for the observed α-glucosidase inhibition. Therefore, a series of twelve arylsulfonyl esters of carvacrol and thymol was prepared. These compounds showed interesting physicochemical properties in silico. Their α-glucosidase inhibition evaluation revealed three compounds with half maximal inhibitory concentration values in the low micromolar range (≅ 2.5 μM), i.e., fifty times more active than acarbose. These compounds showed good selectivity for α-glucosidase compared with α-amylase, β-glucosidase, and β-galactosidase. The two most potent compounds, 7 and 8, are reversible and mixed type α-glucosidase inhibitors. The results indicate that the directed chemical transformation of essential oils can be a useful strategy to discover new α-glucosidase inhibitors.

Oregano (Origanum vulgare L.) essential oil provides anti-inflammatory activity and facilitates wound healing in a human keratinocytes cell model

Skin acts as a protective barrier between the body and the external environment. Skin wounds are a common inflammatory disorder for the solution of which plants and essential oils have been applied as a medical option for centuries. Origanum vulgare essential oil (OEO) is largely used in folk medicine, but its molecular mechanisms of action are not fully known. In this study, we evaluated the anti-inflammatory/antioxidant activity as well as wound healing capacity of a well-characterized OEO on human keratinocytes NCTC 2544 treated with interferon-gamma (IFN-γ) and histamine (H) or subjected to a scratch test. The expression of pro-inflammatory mediators such as reactive oxygen species (ROS), inter-cellular adhesion molecule (ICAM)-1, inducible nitric oxide synthase (iNOS), and cyclooxygenase (COX)-2 were verified. The DNA damage was shown by the formation of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-OHdG) and activation of proliferating cell nuclear antigen (PCNA). Moreover, the abnormal modification of extracellular matrix components (ECM) was examined by determining matrix metalloproteinase (MMP)-1, and −12. Compared to untreated control, OEO showed efficacy in supporting and enhancing the cell motility. In IFN-γ and H treated cells, OEO displayed a significant reduction of ROS, ICAM-1, iNOS, COX-2, 8-OHdG, MMP-1, and MMP-12. OEO proved useful to treat inflammation and support cell motility during wound healing.

Antibacterial Properties of Oregano Essential Oil Encapsulated in Poly(ε-Caprolactone) Nanoparticles

This work describes an outstanding synthesis of poly(ε-caprolactone) nanoparticles of distinct sizes loaded (PCLNP/OEO) or not (PCLNP) with oregano (Origanum vulgare) essential oil (OEO) by the nanoprecipitation method in order investigate the antimicrobial properties against bacteria Escherichia coli and Staphylococcus aureus. OEO antimicrobial activity was achieved by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). FTIR spectra indicated that encapsulation of OEO by PCLNPs was successful. Scanning electron microscopy images revealed that PCLNP and PCLNP/OEO presented spherical shape with diameters around 150 nm, while PCLNP exhibited size distribution raging 158 to 300 nm and zeta potential ranging from -13.8 to -28.5 mV. Thermogravimetric analysis indicated an increase in initial temperature of weight loss for PCLNP/OEO. PCLNP with 80% wt. of OEO has exhibited the highest decrease of growth of bacteria, and MIC against S. aureus and E. coli and MBC only for E. coli, which indicate a promising alternative for designing stable antimicrobial nanoparticles for application in novel food active packaging.

In vitro compatibility of Pimpinella anisum and Origanum vulgare essential oils with nematophagous fungi and their effects against Nacobbus aberrans

The soil nematode Nacobbus aberrans (Thorne & Allen) is one of the recurrent biotic adversities in crops growing under cover, and its presence in the horticultural area of Rio Cuarto, Argentina, is reported from the 1980s to the present day. The use of botanical extracts in combination with biological control agents could be a promising method for the control of this nematode. Nematicidal effects of Pimpinella anisum (anise) and Origanum vulgare (oregano) essential oils (EOs) against second-stage juveniles (J2) of N. aberrans were evaluated in vitro. Fisher LSD tests evidenced significant nematicidal (α = 0.05) effects of the two EOs tested, with LD100 of 200 and 600 µL L−1 for anise and oregano, respectively. Compatibility assays between EOs and five nematophagous fungi were microscopically and macroscopically performed on soil extract solid medium (SESM) conditioned at different water activities (0.99 and 0.98 aw) and incubated at 30, 25 and 20 °C. Purpureocillium lilacinum SR14 was the fungal strain that showed compatibility at levels of spore germination, viability of propagules and growth rate under the different anise oil doses, temperatures and aw assayed. In conclusion, the integrated application of anise EO with the nematophagous fungus, which combines two action mechanisms, could generate, on the one hand, a rapid larval mortality effect caused by the EO and, on the other hand, a parasitic effect that has the advantage of remaining in time under variable environmental conditions.

Antibacterial nanobiocomposite based on halloysite nanotubes and extracted xylan from bagasse pith

In this study, the antibacterial polyelectrolyte carboxymethyl xylan/chitosan (CMX/CS) films incorporated with halloysite nanotubes (HNTs) and Origanum vulgare essential oil (OEO) were prepared and then characterized. Xylan-rich hemicelluloses (62.23%) were extracted from sugarcane bagasse pith and then subjected to carboxymethylation. FTIR analysis revealed the successful modification of hemicelluloses. The irregular white spots in SEM images of nanobiocomposites revealed the entrance of HNTs into the polymer matrix. EDX maps manifested that the density of Si and Al atoms increased, as the amount of HNT increased. The observed discontinuities for EO-containing nanobiocomposites in the SEM images may be attributed to the hydrophobic nature of EO. The barrier properties of the nanocomposites improved by incorporation of HNTs and O. vulgare. The tensile strength of nanocomposite improved significantly by incorporating HNT. EO/HNT-containing films exhibited a higher antibacterial activity against selected bacteria than HNT-containing films.

Using α-chitin nanocrystals to improve the final properties of poly (vinyl alcohol) films with Origanum vulgare essential oil

-In the present work, nanocomposite films based on poly(vinyl alcohol) (PVA) containing different amounts of Origanum vulgare essential oil (OEO, 0, 0.5, 1, 1.5 and 2% v/v) were reinforced with 0.5% (w/v) of alphachitin nanocrystals (α-CHNC, from shrimp and from lobster) and prepared by solvent casting. Another set of films was prepared without α –CHNC to assess the effect of the nanocrystals on the final properties of the films. The obtained nanocomposite films were homogeneous and showed better thermal stability and mechanical properties. After exposure the nanocomposite films to ultraviolet radiation, the obtained data revealed that the presence of α-CHNC into the materials has a retarding effect on their loss of mechanical properties. It was also shown that the antioxidant activity and the total phenolic content of the materials increased with the augmentation of OEO and with the antioxidant release time. Interestingly, the nanocomposite films made of chitin nanocrystals from shrimp showed better total phenolic content than the unfilled films and the nanocomposite films made of chitin nanocrystals from lobster over the first 48 h. Henceforward, this study demonstrated the potential of the nanocomposite films based on PVA, OEO and reinforced with α-CHNC for active food-packaging applications.

Antibacterial Effects of Oregano Essential Oil (OEO) and Its Potential Applications

Essential oils (EOs) are commonly used in food industry, due that they possess antioxidative and antimicrobial properties. There are few essential oils that have been used in medicine, due to its potent antibacterial activity against intrahospital pathogens. OEO has experimentally shown potent antibacterial effect on nosocomial Gram-positive bacteria, therefore it can be very useful in hospital environments, where there are many bacterial pathogens, which are the etiological agents of nosocomial infections and most of them are resistant to several antibiotics.&#x0D; Objective: The aim of this study was to determine antimicrobial effect of OEO on most frequent bacterial intrahospital pathogens: MRSA, MRSE comparatively to selected ATCC bacterial reference strains.&#x0D; Methods: This experimental study investigates the antibacterial action of oregano (Origanum vulgare) essential oil (OvEO) on two human pathogens: Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE) Here, we used OEO against one of the most prominent antibiotic-resistant bacterial strains: methicillin-resistant SA (MRSAmecA+ = Meticillin Resistant SA and mecA- = Meticillin Resistance SA ), methicillin-resistant SE (MRSEmecA+ = Meticillin Resistance Staphylococcus epidermidis mecA+) and reference strains: S. aureus ATCC 700699, S. epidermidis ATCC 359845 and E. coli ATCC 25922. Bactericidal effects of the OEO on these bacteria were mainly evaluated using undiluted and four serial dilutions in coconut oil (CCO) l: 1:10, 1:100, 1:200, 1:400.&#x0D; Results: OEO, undiluted and 4 serial dilutions showed potent antibacterial activity against all strains tested. In conclusion, this OEO could be used as an alternative in medicine. The ability of OEO to inhibit and kill clinical Multi-Drug-Resistant (MDR): MRSA and MRSE strains, highlights it´s potential for use in the management of drug-resistant MDR infections in hospitals wards.

Effect of Origanum vulgare, Eugenia aromatica and Cinnamomum zeylanicum Essential Oils as Welfare Promoters in Gilthead Seabream during Slaughter

The potential of three essential oils, Origanum vulgare, Eugenia aromatica and Cinnamomum zeylanicum as slaughter anaesthetic agents, is presently assessed. Commercial stunning methods inducing rapid unconsciousness in fish before slaughtering, is urgently required. For now there is no acceptable method that can ensure kill fish humanely and all the commercially used methods of slaughter for farmed fish include a prolonged period of consciousness. Four slaughtering methods were applied, over-dose of four anaesthetics (three essential oils Origanum vulgare, Eugenia aromatica, Cinnamomum zeylanicum and 2-phenoxyethanol), asphyxia, bleeding and immersion in ice-water, in gilthead seabream (Sparus aurata L.). Asphyxia, considered inhumane, but solely used in all wild fish, is also being assessed in Atlantic horse mackerel (Trachurus trachurus L.). Plasma cortisol and DNA fragmentation were measured as indicators, to assess stress response and genotoxicity of essential oils. Overdose of all examined essential oils, proved to induce less stress in comparison to asphyxia, bleeding and immersion in ice-water. O. vulgare, E. aromatica and C. zeylanicum demonstrated higher efficiency in blocking plasma cortisol response to stress in gilthead seabream and lower genotoxic effect, compared to other slaughtering techniques. Asphyxia was confirmed as very stressful slaughtering method in both experimental and wild fish.

Chemical Composition, Antimicrobial activity, in Vitro Cytotoxicity and Leukotoxin Neutralization of Essential Oil from Origanum vulgare against Aggregatibacter actinomycetemcomitans.

In this study, the essential oil of Origanum vulgare was evaluated for putative antibacterial activity against six clinical strains and five reference strains of Aggregatibacter actinomycetemcomitans, in comparison with some antimicrobials. The chemical composition of the essential oil was analyzed, using chromatography (CG) and gas chromatography–mass spectrometry coupled (CG–MS). The major compounds in the oil were Carvacrol (32.36%), α-terpineol (16.70%), p-cymene (16.24%), and Thymol (12.05%). The antimicrobial activity was determined by an agar well diffusion test. A broth microdilution method was used to study the minimal inhibitory concentration (MIC). The minimal bactericidal concentration (MBC) was also determined. The cytotoxicity of the essential oil (IC50) was <125 µg/mL for THP-1 cells, which was high in comparison with different MIC values for the A. actinomycetemcomitans strains. O. vulgare essential oil did not interfere with the neutralizing capacity of Psidium guajava against the A. actinomycetemcomitans leukotoxin. In addition, it was shown that the O. vulgare EO had an antibacterial effect against A. actinomycetemcomitans on a similar level as some tested antimicrobials. In view of these findings, we suggest that O.vulgare EO may be used as an adjuvant for prevention and treatment of periodontal diseases associated to A. actinomycetemcomitans. In addition, it can be used together with the previously tested leukotoxin neutralizing Psidium guajava.

Essential Oils as Natural Biocides in Conservation of Cultural Heritage.

Essential oils (EOs) have been known for a long time, and they are used in several fields such as medicine and aromatherapy, as well as in the food and pharmaceutical industries. In the last decade, EOs have also been applied to contrast the biodeterioration of cultural heritage, representing a powerful resource in green conservation strategies. In this study, an integrated approach based on microscopic observation, in vitro culture, and molecular investigation was preliminarily employed to identify biological systems colonizing wooden artworks. In order to contrast the biodeterioration processes induced by fungal colonization (Aspergillus flavus) or insect infestation (Anobium punctatum), wooden artworks were exposed to the volatile compound of Origanum vulgare or Thymus vulgaris essential oils (EOs), the chemical composition of which was determined by GC–MS using both polar and apolar columns. Artwork exposure was performed in ad-hoc-assembled “clean chambers.” Evaluating the effects on biological systems, the compatibility with artwork constitutive materials, and the lack of negative effects on human health and environmental pollution, the use of EOs as a valid alternative to traditional biocides must be considered.