Origanum vulgare essential oil and carvacrol: natural alternatives against resistant bacteria / Óleo essencial de origanum vulgare e carvacrol: alternativas naturais contra bactérias resistentes / El aceite esencial de origanum vulgare y el carvacrol: alternativos naturales contra las bacterias resistentes

Bacteria that are resistant to several antibiotics are a serious One Health problem, as new alternatives for treatment do not appear at the same speed. Thus, the aim of this work was to carry out a survey of studies involving the activity of the essential oil of O. vulgare and its isolated compound carvacrol on antibiotic-resistant bacteria. To this end, a qualitative review of the literature was carried out in the PubMed database from 2015 to 2020. Both for the essential oil and for the isolated compound, the inhibitory action extends to strains often associated with difficult-to-treat infections such as oxacillin and vancomycin-resistant Staphylococcus aureus, ß-lactamase-producing strains, carbapenemases, among others. The point that distinguishes the studies is the type of methodology used in the tests, with studies with carvacrol more directed towards mechanisms of molecular action and application in cells and animals, while those with oils are more preliminary. Although these substances have potential to control resistant bacteria, more research is needed to enable their use.

Bactérias resistentes a vários antibióticos são um grave problema para a Saúde Única, pois novas alternativas de tratamento não aparecem na mesma velocidade. Assim, o objetivo deste trabalho foi realizar um levantamento de estudos envolvendo a atividade do óleo essencial de O. vulgare e seu composto isolado, carvacrol, sobre bactérias resistentes a antibióticos. Para tanto, foi realizada uma revisão qualitativa da literatura na base de dados PubMed no período de 2015 a 2020. Tanto para o óleo essencial quanto para o composto isolado, a ação inibitória se estende a cepas frequentemente associadas a infecções de difícil tratamento como Staphylococcus aureus resistente à oxacilina e vancomicina, cepas produtoras de ß-lactamase, carbapenemases, entre outras. O ponto que diferencia os estudos é o tipo de metodologia utilizada nos testes, sendo os estudos com carvacrol mais direcionados para mecanismos de ação molecular e aplicação em células e animais, enquanto os com óleos são mais preliminares. Embora essas substâncias tenham potencial para controlar bactérias resistentes, mais pesquisas são necessárias para viabilizar seu uso.

Las bacterias resistentes a diversos antibióticos son un grave problema para la Sanidad Única, ya que las nuevas alternativas de tratamiento no aparecen a la misma velocidad. Así pues, el objetivo de este trabajo fue realizar una encuesta sobre los estudios relativos a la actividad del aceite esencial de O. vulgare y su compuesto aislado, el carvacrol, sobre las bacterias resistentes a los antibióticos. Para ello, se realizó una revisión bibliográfica cualitativa en la base de datos PubMed en el periodo comprendido entre 2015 y 2020. Tanto para el aceite esencial como para el compuesto aislado, la acción inhibidora se extiende a cepas frecuentemente asociadas a infecciones de difícil tratamiento como el Staphylococcus aureus resistente a la oxacilina y a la vancomicina, cepas productoras de ß-lactamasas, carbapenemasas, entre otras. El punto que diferencia los estudios es el tipo de metodología utilizada en las pruebas, siendo los estudios con carvacrol más dirigidos a mecanismos de acción molecular y aplicación en células y animales, mientras que los de aceites son más preliminares. Aunque estas sustancias tienen potencial para controlar las bacterias resistentes, es necesario seguir investigando para que su uso sea viable.

Formulation and antimicrobial activity evaluation of a 0. 2% chlorhexidine canine mouthwash with essential oils / Formulación y evaluación de la actividad antimicrobiana de un enjuague bucal canino de clorhexidina al 2% y aceites esenciales

Background: Periodontal disease is the infection and inflammation of the gums, bones, and tissues involved in teeth support, and it is one of the most common diseases affecting pet dogs. Essential oils have shown antimicrobial activity against bacteria causing periodontal disease; therefore, they are considered potential therapeutic agents. Objectives: The main objective was to formulate and evaluate the antimicrobial activity of a 0.2% chlorhexidine canine mouthwash with essential oils. Methods: Three microemulsion formulations were obtained by constructing a pseudo-ternary phase diagram using the phase titration method. Different surfactant agents were evaluated, and hydrogenated castor oil was selected as the emulsifier agent. The antimicrobial activity of oregano essential oil (Origanum vulgare), thyme essential oil (Thymus vulgaris), and the three formulations were evaluated against Staphylococcus aureus, Streptococcus mutans, Streptococcus salivarius, and Escherichia coli. Results: Pure thyme and oregano essential oils showed higher antimicrobial activity than a 0,2% chlorhexidine solution. The formulations with essential oils plus chlorhexidine and chlorhexidine alone showed antimicrobial activity. The formulation containing only essential oils did not show antimicrobial activity. Conclusions: A canine mouthwash was formulated with chlorhexidine and thyme, and oregano essential oil. Based on the evaluation of antimicrobial activity, two of the proposed formulations could be a therapeutic option to reduce the risk and prevent periodontal disease in canines

Antecedentes: La enfermedad periodontal es la infección e inflamación de las encías, huesos y tejidos que brindan soporte a los dientes, es una de las enfermedades más comunes que afectan a los perros de compañía. Los aceites esenciales han mostrado actividad antimicrobiana contra las bacterias que causan la enfermedad periodontal; por lo tanto, son considerados como potenciales agentes terapéuticos. Objetivos: El objetivo principal de este trabajo fue formular y evaluar la actividad antimicrobiana de un colutorio canino de clorhexidina al 0,2% con aceites esenciales. Métodos: Se obtuvo tres formulaciones en microemulsión mediante la construcción de un diagrama de fase pseudoternario por el método de titulación de fase. Se evaluaron diferentes tensioactivos y se seleccionó el aceite de ricino hidrogenado como agente emulsificante de la formulación. La actividad antimicrobiana del aceite esencial de orégano (Origanum vulgare), el aceite esencial de tomillo (Thymus vulgaris) y las tres formulaciones fue evaluada contra Staphylococcus aureus, Streptococcus mutans, Streptococcus salivarius y Escherichia coli. Resultados: Los aceites esenciales puros de tomillo y orégano mostraron una mayor actividad antimicrobiana que una solución de clorhexidina al 0,2%. Las formulaciones con aceites esenciales más clorhexidina y únicamente clorhexidina mostraron actividad antimicrobiana. Mientras que la formulación que contiene solo aceites esenciales no mostró actividad antimicrobiana. Conclusión: Se formuló un enjuague bucal canino con clorhexidina y aceite esencial de tomillo y orégano. Según la evaluación de la actividad antimicrobiana, dos de las formulaciones propuestas podrían ser una opción terapéutica para disminuir el riesgo y prevenir la enfermedad periodontal en caninos

Identificación genética del orégano de Putre (Origanum vulgare L) mediante ITS y microsatélites, una especie reconocida en Chile con Sello de Origen / Genetic identification of the Putre's oregano (Origanum vulgare L) by ITS and microsatellites, a species recognized in Chile with Seal of Origin

Putre ́s oregano (Origanum vulgare L.) is a variety of oregano that grown in the Arica-Parinacota Region. Its organoleptic attributes and unique production conditions have earned it a certification with Geographical Indication (GI). However, the demands of the markets require a scientific-technological support for identification and authentication of materials. In this context, was proposed to identify Putre's oregano by phylogenetic relationships based on the use of molecular markers SSR and "DNA Barcode". The results showed that when comparing materials from different sources of Putre ́s oregano versus information from certified germplasms and GenBank sequences, added to the analysis with nuclear genetic markers, Putre ́s oregano corresponds to the species Origanum vulgare L. subsp virens. This precise identification will support the correct differentiation and authentication of this genotype, serving in addition to supporting the GI.

El orégano de Putre (Origanum vulgare L.) es una variedad de orégano que se cultiva en la Región de Arica y Parinacota. Sus atributos organolépticos y condiciones únicas de producción lo han hecho acreedor de una certificación con Indicación Geográfica (IG). Sin embargo, las exigencias de los mercados requieren de un respaldo científico-tecnológico de identificación y autenticación de materiales. En este contexto, se propuso identificar el orégano de Putre mediante relaciones filogenéticas a partir del uso de marcadores moleculares SSR y "DNA Barcode". Los resultados demostraron que al comparar los materiales de distintas procedencias de orégano de Putre versus la información desde germoplasmas certificados y secuencias de GenBank, sumado al análisis con marcadores genéticos nucleares, el orégano de Putre corresponde a la especie Origanum vulgare L. subsp virens. Esta identificación precisa dará soporte a la correcta diferenciación y autenticación de este genotipo, sirviendo además de apoyo a la IG.

Processamento e caracterização de creme de queijo coalho com óleo de peixe / Processing and characterization of coalho cheese cream with fish oil

O óleo de peixe é fonte de ômega 3, que atua no combate, prevenção e/ou tratamento de doenças crônicas. O queijo coalho é bastante consumido no Nordeste brasileiro, e na forma de creme adicionado de óleo de peixe torna-se uma nova alternativa para o consumidor. Assim, objetivou-se desenvolver e avaliar formulações de creme de queijo coalho (CQQ) com orégano, com ou sem óleo de peixe. Inicialmente, foi realizada uma pesquisa com 70 consumidores de queijo, seguida da elaboração de três formulações de CQQ (F1: sem óleo de peixe; F2: com 0,54g óleo de peixe; F3: com 1,08g de óleo de peixe). Obtidos os CQQs, as formulações (F1, F2 e F3) foram avaliadas no que se refere a: fungos, coliformes totais e termotolerantes, estafilococus coagulase positiva e Salmonella sp; aceitação e preferência sensorial; composição centesimal, fenólicos totais, atividade antioxidante, pH, acidez total titulável e valor calórico. O sabor foi o fator mais importante na escolha de um produto, sendo o ômega 3 (54,28%) e o orégano (57,14%) escolhidos pela maioria dos entrevistados. Todas as formulações estavam seguras microbiologicamente e apresentaram a mesma aceitabilidade e preferência sensorial. A aceitabilidade variou entre 7,43 a 8,13. As formulações de CQQ são de acordo com a legislação, desnatadas (1,77 a 2,66% de lipídios), têm muito alta umidade (≥55%) e baixa acidez (3,12 a 3,28g ácido lácteo/100g), e apresentaram expressiva atividade antioxidante e potencial para comercialização (índice de aceitação ≥70%). Os CQQs são viáveis para incorporação de óleo de peixe, sendo um produto fonte de ômega 3 e que pode apresentar propriedade funcional. (AU)

Fish oil is a source of omega 3 that acts in the fight, prevention and/or treatment of chronic diseases. Coalho cheese is largely consumed in the Northeastern Brazil, and in the form of cream added with fish oil it becomes a new alternative to consumers. Thus, the aim of this study was to develop and assess coalho cheese cream (CCC) formulations added with oregano, with or without fish oil. Firstly, a survey was conducted with 70 cheese consumers, followed by the preparation of three CCC formulations (F1: without fish oil; F2: with 0.54g of fish oil; F3: with 1.08g of fish oil). The CCC formulations (F1, F2 and F3) were analyzed for fungi, total and thermotolerant coliforms, coagulase-positive staphylococci, and Salmonella sp.; acceptability and sensory preference were also assessed, as well as the centesimal composition, total phenols, antioxidant activity, pH, total titratable acidity and calories. Taste was the most important factor in the choice of the product, being omega 3 (54.28%) and oregano (57.14%) chosen by the majority of the participants. All formulations were microbiologically safe and had the same acceptability and sensory preference. The acceptability index varied from 7.43 to 8.13. The CCC formulations are in conformity with legislation, are low fat (1.77 to 2.66% of lipids), have high moisture (>55%) and low acidity (3.12 to 3.28g of lactic acid/100g), and have an expressive antioxidant activity and marketing potential (acceptability was >70%). The CCCs are viable for incorporation of fish oil, being an omega-3 source product with functional property. (AU)

Influence of lipids and proteins amounts and pH values on the inhibitory effects of Origanum vulgare L. essential oil against Escherichia coli and Salmonella Typhimurium

Origanum vulgare L. (OVEO) essential oil has been considered a candidate antimicrobial for use in food conservation systems. However, studies on the influence of concomitant variations of different food components or physicochemical parameters on the antibacterial properties of OVEO are scarce. This study assessed the influence of concomitant variations in amounts of proteins - PTN (4.0, 6.0 or 8.0 g/100 mL) and lipids - LIP (3.75, 5.0 or 6.25 g/100 mL) and pH values (5.0, 5.5 or 6.0) in cultivation medium on the inhibitory effects of OVEO against Escherichia coli (EC) and Salmonella Typhimurium (ST). Lowest minimum inhibitory concentration values of OVEO against EC and ST were observed in media with the highest LIP amounts regardless the PTN amount and pH value. In absorbance based microtiter plate assay (MPA), for both EC and ST, OVEO caused the lowest Grmax values in medium containing the highest LIP and PTN amounts and lowest pH value. Highest Grmax values for EC and ST were observed in medium containing the lowest LIP and PTN amount and highest pH value. Grmax values estimated from viable counts of EC and ST in tested media with OVEO confirmed bacterial growth behavior similar to that observed in MPA. Overall, the LIP amount in media was as the most influential factor to enhance the antibacterial effects of OVEO. These results indicate that the concomitant influence of LIP and PTN amounts and pH values on the antibacterial effects of OVEO should be considered for optimizing its antimicrobial efficacy in foods.

Optimization of Extraction Process of Thymol and Carvacrol in Origanum vulgare by Box-Behnken Design-Response Surface Methodology / 中国药学杂志

OBJECTIVE: To optimize the extraction process of thymol and carvacrol in Origanum vulgare by Box-Behnken design-response surface methodology. METHODS: On the basis of single factor experiment, taking the sum of extraction rates of thymol and carvicol as the evaluation index, Box-Behnken design was used to investigate the effects of ethanol concentration, liquid-solid ratio and medicinal powder on the extraction rate. RESULTS: The optimal extraction parameters were as follows: ethanol concentration was 80%, liquid to solid ratio was 13∶1 (mL/g), medicinal powder passing through 40 meshes was used, and the highest extraction rate was 694.80 μg•g-1, with a small deviation from the predicted value. CONCLUSION: The optimal extraction method is simple, with low cost and good predictivity, and it can provide experimental basis for further large-scale production of thymol and carvacrol in Origanum vulgare.

Atividade in vitro do óleo essencial de Origanum vulgare L. em isolados clínicos de Aspergillus spp / In vitro activity of essential oil of Origanum vulgare L. in clinical isolates from Aspergillus spp

Aspergillus fumigatus, A. flavus e A. niger são os mais importantes agentes etiológicos da aspergilose, relevante micose aviária, com tratamento ineficaz e altas taxas de mortalidade. Em vista da importância da aspergilose, da necessidade de prospectar novos fármacos e do potencial terapêutico do óleo essencial de Origanum vulgare L. (OEO), o orégano, objetivou-se avaliar a sensibilidade in vitro de isolados clínicos de Aspergillus spp. em relação ao OEO. O óleo foi obtido por hidrodestilação em Clevenger, e a análise química realizada por cromatografia de massa (GC/MS). Observaram-se 15 diferentes compostos ativos, sendo 4-terpineol, hidrato de sabinene e timol os majoritários. Nos testes de microdiluição em caldo (Reference..., 2008), todos os isolados (n= 23) foram sensíveis ao OEO: A. fumigatus teve CIM entre 28,125mg/mL (0,1875%) e 450mg/mL (3,0%), A. flavus entre 112,5mg/mL (0,75%) e 450mg/mL, e A. niger 112,5mg/mL. CFM variou de 112,5mg/mL a 450mg/mL nos isolados de A. fumigatus, de 225mg/mL (1,5%) a 450mg/mL em A. flavus, e foi de 450mg/mL em A. niger. CIM e CFM foram idênticos em 6/14 isolados, o que demonstra que o óleo com a mesma concentração pode ter capacidade fungistática e fungicida. CIM 90 correspondeu à CIM máxima. Os resultados demonstram a atividade anti-Aspergillus do OEO, com CIM 90 de 450mg/mL (3%).(AU)

Aspergillus fumigatus, A. flavus and A. niger are the most important etiological agents of aspergillosis, a relevant avian mycosis, with innefective treatment and high mortality rates. Due the importance of aspergillosis, the necessity of prospection of new drugs and the therapeutic potential of the essential oil of Origanum vulgare L. (OEO), popularly known as oregano, aims to evaluate the in vitro sensitivity of Aspergillus spp. opposing to OEO. The oil was obtained by hydrodistillation in Clevenger, and the chemical analysis performed by mass chromatography (GC/MS). 15 different active compounds were observed, being 4-terpineol (18.4%), sabinene hydrate (15.6%) and thymol (13.6%), the majority components. In the in vitro susceptibility test, all strains showed sensitivity to OEO, MIC of Aspergillus fumigatus ranged from 28,125mg/mL (0,1875%) to 450mg/mL (3,0%), A. flavus 112,5mg/mL (0,75%) to 450mg/mL, and A. niger 112,5mg/mL. MFC ranged from 112,5mg/mL to 450mg/mL in the A. fumigatus isolates, 225mg/mL (1,5%) to 450mg/mL in A. flavus, and 450mg/mL for A. niger. The MIC and FMC values were identical in 6/14 of the isolated subjects, demonstrating that the oil with the same concentration can have fungistatic and fungicidal capacity. The results demonstrates anti-Aspergillus activities of OEO with CIM90 de 450mg/mL (3%).(AU)

Origanum vulgare L. essential oil inhibits the growth of carbapenem-resistant gram-negative bacteria

Abstract INTRODUCTION: Plant products are sources for drug development against multidrug resistant bacteria. METHODS The antimicrobial activity of Origanum vulgare L. essential oil (OVeo) against carbapenem-resistant strains was assessed by disk-diffusion, microdilution (REMA-Resazurin Microtiter Assay), and time kill assays. RESULTS Carbapenemase production was confirmed for all strains. OVeo exhibited a minimum inhibitory concentration of 0.059% v/v for Klebsiella pneumoniae and Serratia marcescens, and of 0.015 % v/v for Acinetobacter baumannii. A decrease in cell count was observed after a 4 h treatment. CONCLUSIONS OVeo antimicrobial effect was rapid and consistent, making it a candidate for developing alternative therapeutic options against carbapenem-resistant strains.

Uso de antioxidantes naturais em hambúrgueres elaborados com carne mecanicamente separada de aves / Use of natural antioxidants in hamburgers prepared with mechanically separated poultry meat / Uso de antioxidantes naturales en hamburguesas elaboradas con carne mecánicamente separada de aves

Antioxidantes são substâncias utilizadas para preservar alimentos por meio do retardamento da deterioração, da rancidez e descolorações decorrentes da oxidação. Os antioxidantes disponíveis incluem os sintéticos e os naturais, no entanto, devido à possibilidade de efeitos carcinogênicos e mutagênicos, cada vez mais, existe uma busca pelo uso de antioxidantes naturais. A CMS (Carne Mecanicamente Separada) origina-se do processamento da carne, sendo formado pelo dorso, pescoço e da desossa da ave após processamento da carne para formação dos cortes. A legislação brasileira recomenda no máximo até 30% de CMS na produção de hambúrgueres, demonstrando a possibilidade de seu aproveitamento em um produto de maior valor comercial. Além disso, por ser uma carne extremamente processada está mais sujeita à oxidação, o que faz com que seja necessário o uso de antioxidantes visando, principalmente, aumentar o tempo de prateleira. Dessa forma, fazem-se necessárias pesquisas avaliando o uso de antioxidantes naturais, tais como os óleos essenciais. Em pesquisa recente desenvolvida por nosso grupo de pesquisa foi avaliado a produção de hambúrgueres elaborados com CMS de aves (frangos e galinhas) e adicionado de óleo essencial de hortelã ou orégano como antioxidante em diferentes níveis (0,04; 0,06 e 0,08%) e resultados prévios demonstraram uma boa aceitabilidade no teste de preferência para qualquer um dos níveis utilizados. No entanto, os resultados da avaliação da capacidade antioxidante e análise microbiológica devem ser avaliados para se definir o melhor nível de uso dos óleos essenciais de orégano ou hortelã como antioxidante natural em produtos elaborados com CMS de aves.(AU)

Antioxidants are used to preserve food by delaying deterioration, rancidity and discoloration caused by oxidation. Antioxidants can be either synthetic or natural; however, due to the possibility of carcinogenic and mutagenic effects, there has been an increasing search for the use of natural antioxidants. Mechanically separated meat (MSM) originates from the meat processing, being formed by the back, neck and the deboning process of poultry, and the subsequent processing of the meat to form the cuts. The Brazilian legislation recommends a maximum of 30% of MSM in the production of hamburgers, demonstrating the possibility of its use in a product with greater commercial value. Moreover, since this is an extremely processed meat, it is more prone to oxidation, requiring the use of antioxidants to increase shelf life. Thus, research is needed to evaluate the use of natural antioxidants such as essential oils. In recent research developed by this research group, the production of hamburgers made with MSM from poultry and the addition of mint or oregano essential oil as antioxidant at different levels (0.04, 0.06, and 0.08%), with prior results showing good acceptability in the preference test for all the levels used. However, the antioxidant capacity assessment and microbiological analysis must be evaluated in order to determine the optimal usage level of oregano or mint essential oils as natural antioxidants in products made with poultry MSM.(AU)

Los antioxidantes son sustancias utilizadas para preservar los alimentos por medio de retraso del deterioro, de la rancidez y de las decoloraciones resultantes de la oxidación. Los antioxidantes disponibles incluyen los sintéticos y los naturales, sin embargo, debido a la posibilidad de efectos carcinogénicos y mutagénicos, cada vez más existen búsquedas por el uso de antioxidantes naturales. La CMS (carne mecánicamente separada) se origina del procesamiento de la carne, siendo formado por el dorso, el cuello y el deshuesado del ave después del procesamiento de la carne para la formación de los cortes. La legislación brasileña recomienda al máximo hasta un 30% de CMS en la producción de hamburguesas, demostrando la posibilidad de su aprovechamiento en un producto de mayor valor comercial. Además, por ser una carne extremadamente procesada está más sujeta a la oxidación, lo que hace que es necesario el uso de antioxidantes, buscando principalmente aumentar el tiempo de estantería. De esa forma, se hacen necesarias investigaciones evaluando el uso de antioxidantes naturales, tales como los aceites esenciales. En investigación reciente desarrollada por nuestro grupo de investigadores se evaluó la producción de hamburguesas elaboradas con CMS de aves (pollos y gallinas), agregado de aceite esencial de menta u orégano como antioxidante en diferentes niveles (0,04, 0,06 y 0, 08%), resultados previos demostraron una buena aceptación en la prueba de preferencia para cualquiera de los niveles utilizados. Sin embargo, los resultados de la evaluación de capacidad antioxidante y el análisis microbiológico deben ser evaluados para definir el mejor nivel de uso de los aceites esenciales de orégano o menta como antioxidante natural en productos elaborados con CMS de aves.(AU)

Efecto Antibacteriano de la Infusión de Orégano ( Origanum vulgare ) sobre el Crecimiento in Vitro de Streptococcus mutans, 2015 / Antibacterial Effect of Oregano Infusion ( Origanum vulgare ) on in Vitro Growth of Streptococcus mutans, 2015

RESUMEN: El Streptococcus mutans es una de las principales bacterias que participa en el desarrollo de la caries dental, una enfermedad de alta prevalencia en la población mundial, y por ende un problema de salud pública. Hoy se intentan buscar alternativas para su prevención, una de ellas es la fitoterapia o uso de plantas medicinales con fines terapéutico beneficiosos para la salud. Evaluar efecto antibacteriano del Origanum vulgare a diferentes concentraciones sobre el crecimiento in vitro de Streptococcus mutans. Se utilizaron cepas bacterianas de Streptococcus mutans previamente aisladas, se realizó una siembra bacteriana en 24 placas Petri con agar mitis salivarius. Se prepararon infusiones de orégano a 8 concentraciones diferentes (1 %, 5 % y 10 %, 20 %, 40 %, 60 %, 80 % y 100 %) y se aplicaron en perforaciones realizadas previamente en las placas de agar (4 perforaciones por placa para las infusiones de orégano y 2 para las placas de controles). Se llevó a incubadora por 48 horas y posteriormente se realizó la medición de los halos de inhibición. Los resultados fueron negativos para las infusiones de orégano al 1 %, 5 % y 10 %, debido a que no presentaron halos de inhibición bacteriana; mientras que para las infusiones al 20 %, 40 %, 60 %, 80 % y 100 % los resultados fueron positivos. El orégano posee efecto antibacteriano sobre el crecimiento de Streptococcus mutans en infusiones sobre el 20 % de concentración, siendo la solución madre preparada a partir de 20 gramos de hojas secas de orégano (Origanum vulgare) y 200 ml de agua destilada hervida. Este efecto es antibacteriano es directamente proporcional a la concentración de la infusión. El orégano podría ser utilizado como una alternativa de colutorio, pasta dental u otros coadyuvantes de higiene bucal para prevenir la aparición de caries.

ABSTRACT: Streptococcus mutans is one of the main bacteria in the development of dental caries, a disease with high prevalence in the world population, and therefore a public health problem. There is current research to find prevention alternatives one of these is the use of medicinal plants for therapeutic purposes beneficial to health. To evaluate the antibacterial effect of Origanum vulgare at different concentrations on in vitro growth of Streptococcus mutans, previously isolated bacterial strains of Streptococcus mutans were used. Bacterial seeding was carried out in 24 petri dishes with agar Mitis salivarius. Oregano infusions were prepared at 8 different concentrations (1 %, 5 % and 10 %, 20 %, 40 %, 60 %, 80 % and 100 %) and applied in predrilled holes in the agar plates (4 perforations per plate for the oregano infusions and 2 for control plates). They were maintained in an incubator for 48 hours and measurement of the inhibition zones was subsequently carried out. The results were negative for infusions of oregano at 1 %, 5 % and 10 %, as they did not present halos of bacterial inhibition; while results were positive for infusions at 20 %, 40 %, 60 %, 80 % and 100 %. Results show that oregano has an antibacterial effect on the growth of Streptococcus mutans in infusion concentrations above 20 %, with the basic solution prepared from 20 g of dried oregano leaves (Origanum vulgare) and 200 ml of boiled distilled water. This antibacterial effect is directly proportional to the concentration of the infusion. Oregano could be used as an alternative mouthwash, toothpaste or other oral hygiene adjuvants to prevent the incidence of caries.

Estudio in vitro del Efecto Antibacteriano de la Oleorresina de Copaifera reticulata y el Aceite Esencial de Origanum majoricum Frente a Streptococcus mutans y Enterococcus Faecalis Bacterias de Importancia en Patologías Orales / In vitro Study of the Antibacterial Effect of Oleoresin of Copaifera reticulata and the Essential Oil of Origanum majoricum against Streptococcus mutans and Enterococcus faecalis Bacteria of Importance in Oral Pathologies

RESUMEN: El objetivo del estudio fue determinar el efecto antibacteriano in vitro de la oleorresina de Copaifera reticulata (C. reticulata) "copaiba" y del aceite esencial de Oreganum majoricum (O. majoricum) "orégano" frente a Streptococcus mutans (S. mutans) y Enterococcus faecalis (E. faecalis). Se desarrollaron pruebas de sensibilidad activando primero las cepas bacterias a enfrentar. La oleorresina de copaiba fue diluida con dimetilsulfósido (DMSO), obteniéndose al final concentraciones a probar de 100 %, 50 %, 25 %, y 12,5 %. En relación al aceite esencial de orégano este se probó solamente al 100 %. Para la prueba de difusión en agar con discos, se tomaron inóculos 100 µL de cada cepa bacteriana a una turbidez de 0,5 de Mc Farlam, para ser sembrados por diseminación en placas de tripticasa soya agar, para luego colocar los discos de forma equidistante cargados con las diferentes concentraciones de los productos naturales, se utilizaron como control positivo a la clorhexidina al 0,12 % y al DMSO como control negativo. Se incubaron las placas por el método de la vela en extinción a 37 °C, por un periodo de 24 horas, pasado el tiempo se realizó la lectura de los halos de inhibición. Los resultados obtenidos por la copaiba, determinaron un efecto antibacteriano en sus cuatro concentraciones, siendo los mayores halos de inhibición a la concentración del 100 %, copaiba genero mayores halos promedios para S, mutans de 30,00 ± 0,00 mm y para E. faecalis de 8,3 ± 0,50 mm. Para el caso del orégano se producen halos a la concentración del 100 % con un promedio de 25,3 ± 0,96 mm para S. mutans y para E. faecalis de 9,5 ± 1,29 mm. Se concluye del estudio que tanto copaiba como el orégano presentan un efecto antibacteriano para ambas bacterias, siendo su mayor efecto antibacteriano para ambos productos naturales sobre S. mutans.

ABSTRACT: The objective of the study was to determine the in vitro antibacterial effect of the oleoresin of Copaifera reticulata (C. reticulata) "copaiba" and of the essential oil of Oreganum majoricum (O. majoricum) "oregano" against Streptococcus mutans (S. mutans) and Enterococcus faecalis (E. faecalis). Sensitivity tests were developed by first activating the bacteria strains to be confronted. The oleoresin of copaiba was diluted with dimethylsulphoside (DMSO), obtaining final concentrations to be tested of 100 %, 50 %, 25 %, and 12.5 %. In relation to the essential oil of oregano, it was only 100 % tested. For the disk agar diffusion test, 100 mL of each bacterial strain was taken at a turbidity of 0.5 of Mc Farlam, to be planted by dissecting trypticase soy agar plates, and then placing the disks equidistantly loaded with the different concentrations of natural products; 0.12 % chlorhexidine was used as a positive control and DMSO as negative control. The plates were incubated by the candle method in extinction at 37 °C, for a period of 24 hours, after which time the inhibition halos were read. The results obtained by the copaiba, determined an antibacterial effect in its four concentrations, being the biggest halos of inhibition at the concentration of 100 %, copaiba genus higher average halos for S. mutans of 30.00 ± 0.00 mm and for E. faecalis of 8.3 ± 0.50 mm. In the case of oregano, haloes are produced at a concentration of 100 % with an average of 25.3 ± 0.96 mm for S. mutans and for E. faecalis 9.5 ± 1.29 mm. It is concluded from the study that both copaiba and oregano present an antibacterial effect for both bacteria, being its greater antibacterial effect for both natural products on S. mutans.

Efecto del aceite esencial de orégano (Lippia origanoides) sobre metabolitos sanguíneos en pollos de engorde / Effect of oregano essential oil (Lippia origanoides) on blood metabolites in broiler chickens / Efeito do óleo essencial de orégano (Lippia origanoides) sobre metabolitos sanguíneos em frangos de corte

Resumen Objetivo: evaluar parámetros sanguíneos en pollos de engorde de la línea genética Cobb500, luego de la administración de aceite esencial de orégano (Lippia origanoides) (AEO). Materiales y métodos: se utilizaron 200 pollos de línea genética Cobb 500 y se realizaron mediciones los días 14, 28 y 42. Los animales fueron aleatorizados a una de dos dietas: dieta comercial con antibiótico y sin este. A esta última se adicionaron diferentes concentraciones de AEO (75 ppm, 100 ppm o 200 ppm AEO). Se realizó un diseño estadístico de bloques al azar en un arreglo de parcelas dividas. Resultados: los pollos del grupo D5 (200 ppm) presentaron mayores valores en glucosa, fosfatasa y fósforo que los pollos alimentados con antibiótico (D2) a lo largo del experimento. Conclusión: la adición de 200 ppm de AEO en el alimento de pollos de engorde de la línea genética Cobb 500 induce una mejora en metabolitos sanguíneos. Este trabajo permitió evaluar las variables metabólicas de pollos que consumieron AEO.

Abstract Objective: To evaluate blood parameters in broiler chickens of the Cobb 500 genetic line, after the administration of oregano essential oil (Lippia origanoides) (OEO). Materials and methods: 200 chickens of the Cobb 500 genetic line were used, and measurements were taken on days 14, 28, and 42. The animals were randomly assigned to one of two diets: commercial diet with and without antibiotic supplementation. To the antibiotic-free diet different concentrations of OEO were added (75 ppm, 100 ppm, or 200 ppm). A statistical randomized block design was used in an array of divided plots. Results: Chickens from group D5 (200 ppm of OEO) had higher values in glucose, phosphatase, and phosphorus than chickens fed with antibiotic supplementation (D2) throughout the experiment. Conclusion: The addition of 200 ppm of OEO in the food of broiler chickens of the Cobb 500 genetic line induces an improvement in blood metabolites. This work allowed evaluating metabolic variables of chickens that consumed OEO.

Resumo Objetivo: avaliar parâmetros sanguíneos em frangos de corte da linha genética Cobb500, após administração de azeite essencial de orégano (Lippia origanoides) (AEO). Materiais e métodos: Foram utilizados 200 frangos de linha genética Cobb 500 e foram realizadas medições nos dias 14, 28 e 42. Os animais foram submetidos aleatoriamente a uma de duas dietas: dieta comercial com antibiótico e sem este. A esta última foram adicionadas diferentes concentrações de AEO (75 ppm, 100 ppm ou 200 ppm AEO). Se realizou um desenho estatístico de blocos aleatórios em uma matriz de parcelas dividas. Resultados: os frangos do grupo D5 (200 ppm) apresentaram maiores valores em glicose, fosfatase e fósforo que os frangos alimentados com antibiótico (D2) ao longo do experimento. Conclusão: a adição de 200 ppm de AEO no alimento de frangos de corte da linha genética Cobb 500 induz a uma melhora em metabolitos sanguíneos. Este trabalho permitiu avaliar as variáveis metabólicas de frangos que consumiram AEO.

Antifungal activity of nanoemulsions encapsulating oregano (Origanum vulgare) essential oil: in vitro study and application in Minas Padrão cheese

ABSTRACT The objective of this study was to evaluate the antifungal activity of nanoemulsions encapsulating essential oil of oregano (Origanum vulgare), both in vitro and after application on Minas Padrão cheese. Nanodispersions were obtained by the phase inversion temperature method. Cladosporium sp., Fusarium sp., and Penicillium sp. genera were isolated from cheese samples and used to evaluate antifungal activity. Minimal inhibitory concentrations of non-encapsulated and encapsulated oregano essential oil were determined, and they were influenced by the encapsulation of the essential oil depending on the type of fungus. The antifungal activity of the nanoencapsulated oregano essential oil in cheese slices showed no evidence of an effect of the MICs, when applied in the matrix. On the other hand, an influence of contact time of the nanoemulsion with the cheese was observed, due to the increase in water activity. It was concluded that nanoencapsulated oregano essential oil presented an inhibitory effect against the three genera of fungi evaluated. If environmental parameters, such as storage temperature and water activity, were controlled, the inhibitory effect of nanoemulsions of oregano oil could possibly be greatly improved, and they could be presented as a potential alternative for the preservation of Minas Padrão cheese against fungal contamination.

Efectividad antimicótica del aceite esencial de orégano de las provincias de Chimborazo y Santa Elena al 100% de concentración sobre Candida albicans / Antimycotic effectiveness of oregano essential oil from the provinces of Chimborazo and Santa Elena at 100% concentration on Candida albicans

Con el objetivo de tratar patologías orales producidas por Candida albicans mediante sustancias alternativas a base de plantas medicinales, se ha planteado identificar la efectividad antimicótica de los aceites esenciales de Orégano de las provincias de Chimborazo y Santa Elena al 100% de concentración sobre Candida albicans, cepas que han sido inoculadas en láminas de acrílico, para lo cual se tomó como medicamento control a Nistatina. Metodología: una vez seleccionado las plantas de orégano, se obtuvo el aceite esencial de las mismas, al 100% de concentración a través de la técnica de arrastre de vapor de agua. La activación de la levadura se realizó con 0,5 en la escala Mc Farland, posteriormente fueron colocadas en vasos estériles, donde se incorporó 50ml de agua más 0,3 y 0.5ml de aceite esencial de Orégano. Para determinar la efectividad del aceite sobre C. albicans se realizó el conteo de las unidades formadoras de colonias mediante el uso de la cámara de Neubauer, en cuatro tiempos; a la vez se respaldó los resultados de esta investigación con la siembra del inoculo, bajo técnica de Digralsky, en dos tiempos: inicial y final. Dando como resultado que ambos aceites esenciales de orégano mostraron diferencias significativas sobre las levaduras en comparación con nistatina. Conclusión: El aceite esencial obtenido de los oréganos provenientes de las provincias de Chimborazo y Santa Elena reveló valores más altos de efectividad antimicótica frente a Candida albicans.

The anti-asthmatic effect of the combined yerba buena (Mentha arvensis Linn.) and oregano (Coleus amboinicus Lour.) leaves in BALB/c mice model of allergic asthma

INTRODUCTION: Asthma is an IgE-mediated inflammatory response characterized by hyperresponsiveness, airway inflammation, and reversible airflow obstruction. Currently, asthma affects 12 - 22% of the population in the Philippines. Anecdotal reports showed that yerba buena (Mentha arvensis Linn.) and oregano (Coleus amboinicus Lour.) are utilized for treating asthma in the folk culture.OBJECTIVE: The objective of this study was to determine the effect of combined Yerba Buena (Mentha arvensis Linn.) and Oregano (Coleus amboinicus Lour.) leaves extract in asthma-induced mice.METHODS:This study investigated the anti-asthmatic activity of the aqueous and methanolic extracts of the combined herbs in asthma-induced mice using immunoglobulin E (IgE) as a parameter.RESULTS: Aqueous- and methanol-treated mice has 50% and 60% reduction in the IgE level, respectively (p = 0.018). The extracts exhibited a significant (p = 0.001) anti-inflammatory activity in mice that further proved its effect on IgE. Moreover, lung histopathology also established the potential effect of the extract through the widening of the alveoli on treated mice.CONCLUSION: Combined Yerba Buena and Oregano aqueous and methanol extracts may have a potential health benefit against asthma.

Celulite em codornas japonesas alimentadas com extrato de orégano nas dietas e inoculadas com Escherichia coli / Cellulitis in Japanese quails fed oregano extract in the diet and inoculated with Escherichia coli

Com o objetivo de avaliar a utilização do extrato de orégano nas dietas de codornas japonesas (Coturnix coturnix japonica) e desafiadas com cepas de Escherichia coli, sobre as características de desempenho, a incidência de celulite aviária e titulação de anticorpos específicos contra antígenos de E. coli, foram utilizadas 360 codornas japonesas, com 90 dias de idade, distribuídas em gaiolas de arame galvanizado em galpão convencional. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 5x2 (extrato de orégano x desafiado ou não com E. oli), totalizando dez tratamentos com seis repetições de seis aves por gaiola. Os níveis do extrato de orégano (EO) avaliados foram: 0,00; 0,025; 0,050; 0,100 e 0,150%. Foram avaliadas características de desempenho produtivo, lesões macroscópicas da celulite após períodos pós-inoculação das cepas e amostras de soro foram colhidas para verificar a titulação de anticorpos nas aves. Os dados obtidos foram submetidos à análise de variância e as médias comparadas pelo Teste T. Foi observado efeito de E. coli sobre todas as características produtivas, independentemente dos níveis de EO avaliados, onde grupos desafiados apresentaram piores resultados de desempenho. As lesões macroscópicas, características da celulite, observadas somente nas aves desafiadas com E. coli foram classificadas como grau leve e sem presença de hemorragias. Para a titulação de anticorpos específicos, houve maior quantificação para aves desafiadas com as cepas de E. coli em relação às não desafiadas. Pode-se concluir que o extrato de orégano suplementado nas rações não se mostrou eficaz frente ao desafio com E. coli em codornas na fase de postura e as aves desafiadas com E. coli apresentaram maiores respostas imunes humoral e celular, em relação às não desafiadas, caracterizadas pelo aumento na titulação de anticorpos e pela lesão macroscópica peitoral, independentemente dos níveis de extrato de orégano avaliados.(AU)

The aim was to evaluate the use of oregano extract in Japanese quail (Coturnix coturnix japonica) diet, challenged with Escherichia coli strains, on performance, incidence of avian cellulitis and of antibody specific antigens against E. coli. Three hundred sixty Japanese quails with 90 days of age were distributed into galvanized wire cages in a conventional shed. The experimental design was completely randomized in factorial 5x2 design (oregano extract x challenged or not with E. coli), totaling ten treatments with six replicates of six birds per cage. Oregano extract levels were 0.00, 0.025, 0.050, 0.100 and 0.150%. Performance productive characteristics were evaluated, macroscopic lesions of cellulitis were measured after post-inoculation of the strains, and serum samples were collected for antibodies during experiment. The data were subjected to analysis of variance and averages compared by T test. Effect of E. coli was observed on all productive characteristics, regardless of the EO level evaluated, where challenged groups showed worse performance results. The macroscopic lesions, characteristic of cellulitis, observed only in birds of groups challenged with E. coli, were classified as mild and without bleeding. For specific antibodies, there was a higher number of birds challenged with E. coli strains in relation to unchallenged birds. It can be concluded that oregano extract supplemented in the diet was not effective against the challenge with E. coli in laying quails, and challenged birds with E. coli showed higher humoral and cellular immune response, compared with unchallenged birds, characterized by increased antibody titer and pectoral macroscopic lesion, regardless of the oregano extract levels evaluated.(AU)

Influencia del aceite esencial de orégano en la elaboración tradicional de quesos: efecto sobre el fermento láctico / Influence of oregano essential oil on traditional Argentinean cheese elaboration: Effect on lactic starter cultures

The aim of this work is to study the oregano essential oil (OEO) composition from Northwestern Argentinean regions and to evaluate its effect on the lactic starter cultures. The oregano used, Origanum vulgare var hirtum, was obtained from Andalgalá, Catamarca. The essential oil presented high amounts of α-terpinene (10%), γ-terpinene (15.1%), terpinen-4-ol (15.5%) and thymol (13.0%) as the main components. No negative effect on growth or metabolic activity of lactic acid bacteria Streptococcus thermophilus CRL 728 and CRL 813, Lactobacillus delbrueckii subsp. bulgaricus CRL 656 and CRL 468, and Lactococcus lactis subsp. lactis CRL 597 up to the maximum concentration (200 μg/g) assayed was observed. No differences in the organoleptic characteristics of semi-hard cheeses flavored with oregano essential oil (200 μg/g) and homemade cheeses flavored with oregano leaves were found. With respect to the microbiological quality of the products, neither enterobacteria nor mold and yeast were detected during ripening in essential-oil flavored cheese compared to control cheese (enterobacteria 2 × 10³ UFC/g) and cheese flavored with oregano leaves (mold/yeast 4 × 10(4) CFU/g). Our results showed that the use of oregano essential oil and lactic starter culture considerably improved cheese quality.

El objetivo de este trabajo fue estudiar la composición del aceite esencial de orégano recolectado en el noroeste argentino y evaluar su efecto sobre algunos fermentos lácticos. El orégano recolectado correspondió a la especie Origanum vulgare var. hirtum proveniente de Andalgalá, Catamarca. En su aceite esencial (obtenido por arrastre con vapor de agua) se detectó principalmente α-terpineno (10%), γ-terpineno (15,1%), terpinen-4-ol (15,5%) y timol (13,0%). El aceite esencial no tuvo efecto inhibitorio (máxima concentración ensayada 200 μg/g) sobre el crecimiento ni sobre la actividad metabólica de Streptococcus thermophilus CRL 728 y CRL 813, de Lactobacillus delbrueckii subsp. bulgaricus CRL 656 y CRL 468, y de Lactococcus lactis subsp. lactis CRL 597. No se observaron diferencias en las características organolépticas de quesos semiduros aromatizados con el aceite esencial (200 μg/g) comparados con quesos artesanales aromatizados con hojas de orégano. Respecto de la calidad microbiológica de los productos, no se detectaron enterobacterias ni hongos o levaduras durante la maduración en los quesos aromatizados con el aceite esencial de orégano comparados con los quesos control, que presentaron desarrollo de enterobacterias (2 × 10³ UFC/g), y con los quesos elaborados con hojas de orégano, en los que hubo desarrollo de hongos/levaduras (4 × 10(4) CFU/g). Los resultados obtenidos demostraron que el uso del aceite esencial de orégano y del fermento láctico incrementó la calidad general de los quesos artesanales.

Effects of essential oils of Rosmarinus officinalis Linn. and Origanum vulgare Linn. from different origins on Sporothrix brasiliensis and Sporothrix schenckii complex / Efeitos dos óleos essenciais de Rosmarinus officinalis Linn. e Origanum vulgare Linn. de diferentes origens em Sporothrix brasiliensis e complexo Sporothrix schenckii

Rosmarinus officinalis L. (rosemary) and Origanum vulgare L. (oregano) are known to have antimicrobial properties, but studies on sporotrichosis are scarce. This study aimed to evaluate the anti-Sporothrix spp. activity of essential oils from commercial products and oils extracted from aerial parts of these plants and analyze their chemical constituents. S. schenckii complex and S. brasiliensis (n: 25) isolated from humans, cats, dogs, and environmental soil were tested through M27-A3 guidelines of CLSI with modification for phytotherapics. The essential oils of R. officinalis L. were similar for MIC50 and MFC50 ≤2.25mg/mL for extracted oil; and 4.5mg/mL and 9mg/mL, respectively, for commercial oil. Both products showed MIC90 of 18mg/mL and MFC90 of 36mg/mL. In O. vulgare L., the extracted oil had better activity with MIC50 and MFC50 ≤2.25mg/mL, and MIC90 and MFC90 of 4.5mg/mL, whereas the commercial oil showed MIC50 and MFC50 of 9mg/mL and MIC90 18mg/mL, respectively, and MFC90 of 36mg/mL. Through gas chromatography (CG/FID), thymol and α-terpinene were majority for extracted oil of O. vulgare L., and carvacrol and γ-terpinene made up the majority of the commercial oil. Both essential oils of R. officinalis L. showed 1,8-cineole and α-pinene as major. The fungal isolates were susceptible to all tested essential oils, including in itraconazole-resistant S. brasiliensis isolates. The extracted and commercial oils of the plants presented in vitro anti-Sporothrix spp. activity, and they are promising for treatment of sporotrichosis, including in cases refractory to itraconazole. More studies should be performed about toxicity and in vivo efficacy for its safe use.(AU)

Rosmarinus officinalis L. (alecrim) e Origanum vulgare L. (orégano) são conhecidos pelas propriedades antimicrobianas, entretanto seus estudos na esporotricose são escassos. Este trabalho objetivou avaliar a atividade anti-Sporothrix spp. de óleos extraídos e comerciais dessas plantas e analisar seus constituintes químicos. Isolados do complexo S. schenckii e S. brasiliensis (n: 25) de humanos, gatos, cães e solo, foram testados pela diretriz M27-A3 do CLSI com modificações para fitoterápicos. Os óleos de R. officinalis L. foram similares com CIM50 e CFM50 ≤2.25mg/mL para extraído; e 4.5mg/mL e 9mg/mL, respectivamente, para comercial. Ambos os produtos demonstraram CIM90 de 18mg/mL e CFM90 de 36mg/mL. Em O. vulgare L., o óleo extraído apresentou melhor atividade com CIM50 e CFM50≤2.25mg/mL e CIM90 e CFM90 de 4.5mg/mL, ao passo que o óleo comercial mostrou CIM50 e CFM50 de 9mg/mL; e CIM90 de 18mg/mL e CFM90 de 36mg/mL. Por meio da cromatografia gasosa (CG/FID), timol e α-terpineno foram majoritários para o óleo extraído de O. vulgare L., e carvacrol e γ-terpineno para o comercial. Ambos os óleos de R. officinalis L. apresentaram 1,8-cineol e α-pineno como prevalentes. Os isolados foram sensíveis a todos os óleos essenciais testados, inclusive S. brasiliensis, resistentes ao itraconazol. Os óleos extraídos e comerciais de R. officinalis L. e O. vulgare L. apresentaram atividade anti-Sporothrix spp. in vitro e são promissores para o tratamento da esporotricose, inclusive em casos refratários ao itraconazol. Mais estudos devem ser realizados sobre toxicidade e eficácia in vivo para seu uso seguro.(AU)

Teste da ação antibacteriana in vitro de óleo essencial comercial de Origanum vulgare (orégano) diante das cepas de Escherichia coli e Staphylococcus aureus / In vitro antibacterial activity of Origanum vulgare (oregano) essential oil against Escherichia coli and Staphylococcus aureus strains

Origanum vulgare (orégano) tem sido reconhecido como uma espécie vegetal que possui várias propriedades terapêuticas, de modo que atualmente seu potencial antimicrobiano vem recebendo um grande interesse científico. Este estudo objetivou avaliar a ação antimicrobiana (bactericida e bacteriostática) do óleo essencial comercial de O. vulgare sobre cepas de Escherichia coli e Staphylococcus aureus , bactérias envolvidas em toxinfecções alimentares. Foram utilizadas cepas padrão (American Type Culture Collection - ATCC) e clínicas e estas foram submetidas à ação do óleo essencial em diferentes concentrações, por meio das técnicas de microdiluição (para determinação da concentração inibitória mínima - CIM) e de macrodiluição (para determinação da concentração bactericida mínima - CBM). Foi possível observar que houve variação do potencial antimicrobiano do óleo essencial entre as cepas utilizadas. Para E. coli ATCC 25922, a CIM foi de 6,25 µL/ mL e a CBM de 12,5 µL/mL, enquanto para a amostra clínica os valores foram 12,5 e 25 µL/mL, respectivamente. Já para S. aureus ATCC 25923, a CIM e a CBM foram de 12,5 µL/ mL, enquanto para a amostra clínica os valores foram 6,25 e 25 µL/mL, respectivamente. Portanto, esse óleo essencial de O. vulgare mostrou poder de inibição do crescimento e viabilidade das cepas ensaiadas. No entanto, novos estudos são necessários para que sejam determinadas as concentrações ideais do orégano como antimicrobiano natural, levando em consideração os fatores que influenciam sua composição e a quantidade e qualidade dos compostos ativos.(AU)

Origanum vulgare (oregano) was recognized as a species with several therapeutic properties. Nowadays, its antimicrobial potential has been receiving a large scientific interest. This study aimed at evaluating the antimicrobial activity (bactericidal and bacteriostatic) of an O. vulgare commercial essential oil against strains of Escherichia coli and Staphylococcus aureus bacteria related to food intoxication and infection. Standard (American Type Culture Collection - ATCC) and clinical strains were submitted to the action of an essential oil in different concentrations through microdilution (for determination of minimum inhibitory concentration - MIC) and macrodilution (for determination of the minimum bactericidal concentration - MBC) techniques. Variation in the antimicrobial potential of an essential oil among the tested strains was observed. For E. coli ATCC 25922, the MIC was 6.25 µL/mL and MBC 12.5 µL/ mL, while for the clinical sample, values varied respectively between 12.5 and 25 µL/mL. For S. aureus ATCC 25923, values of MIC and MBC were 12.5 µL/mL, while for the clinical sample they respectively ​​were 6.25 and 25 µL/mL. Thus, the essential oil of O. vulgare showed inhibition power of growth and viability in the tested strains. However, further studies are necessary to determine the optimal concentrations of oregano to act as a natural antimicrobial, considering the factors that influence their composition, and the quantity and quality of active compounds.(AU)

Habituation of enterotoxigenic Staphylococcus aureus to Origanum vulgare 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.