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.

Global metabolic changes induced by arbuscular mycorrhizal fungi in oregano plants grown under ambient and elevated levels of atmospheric CO2.

Symbiotic plant-microorganisms interaction is a promising approach to avoid the environmental hazards of synthetic fertilizers and pesticides. Among these, arbuscular mycorrhizal fungi (AMF) are known to improve the growth and quality of many plant species; however the detailed metabolic mechanisms behind such beneficial effects are far from complete. Further, elevated levels of atmospheric CO2 (eCO2) could affect such AMF-plant association. Herein, we have investigated the individual and synchronous impact of AMF and eCO2 (620 ppm) on nutrient uptake, growth, photosynthesis, respiration, and levels of primary and secondary metabolites in oregano (Oreganum vulgare), an economically important herbal plant. Enhanced AMF colonization rate and a better mycelial growth were observed in roots of oregano grown under eCO2. Both AMF and eCO2 treatments significantly enhanced the growth and photosynthesis of oregano plants, however much improvements were observed by their synchronous application. eCO2 further increased the AMF-induced dark respiration and accumulation of macro and microelements. Hierarchical clustering analysis of individual primary and secondary metabolites revealed a metabolite-dependent response toward AMF and eCO2. The synchronous application of AMF and eCO2 resulted in promoted accumulation of the majority of the detected sugars, organic acids, amino acids, unsaturated fatty acids, phenolic acids and flavonoids, as compared with the sole treatments. Moreover, AMF and eCO2 acted synergistically in improving the antioxidant capacity and anti-lipid peroxidation activity of oregano. Therefore, this study suggests that AMF treatment induces a global metabolic change in oregano, the effect that is strengthened under eCO2.

Effect of jasmonic acid on major terpenes and density of glandular trichomes in Lippia graveolens kunth (Verbenaceae).

The effect of exogenous application of jasmonic acid (JA) on the concentration of main terpenes and density of glandular trichomes was investigated in the Mexican oregano, propagated from seeds from 3 localities. JA 1 mM was applied locally and to the whole plant. JA locally applied increased the number of trichomes, with a mean of 20 trichomes more with respect to the controls in plants from Tecomavaca and Zapotitlán Salinas, and significantly increased the thymol concentration by 185% systemically and 255% locally, compared to the control. JA applied to the whole plant decreased the number of trichomes and increased the concentration of caryophyllene from 0.79 to 1.7 mg g-1, and α-caryophyllene from 0.3 to 0.8 mg g-1 in plants from San Rafael with reference to water control. The results suggest a plasticity of morphologic and phytochemical responses, and a potential use of JA to improve phenolic monoterpenes and sesquiterpenes production.

Uptake of Cd, Pb, and Ni by Origanum syriacum produced in Lebanon.

Trace metals are found naturally in soil. However, the increase in industrial and agricultural polluting activities has increased trace metal contamination and raised high concerns in the public health sector. The study was conducted on Origanum syriacum, one of the most consumed herbs in the Middle East, and was divided into three parts. (1) Pot experiment: to study the effect of Cd, Pb, or Ni levels in soil on their uptake by O. syriacum. (2) Field samples: collected from major agricultural regions in Lebanon to analyze Cd, Pb, and Ni concentrations in soil and leaves. (3) Sale outlets samples: to measure the levels of Cd, Pb, and Ni in O. syriacum tissues in the market. Results showed that there was a positive correlation between levels of Cd, Pb, and Ni in soil and those in O. syriacum tissues. None of the field samples contained Pb or Ni that exceeded the maximum allowable limits (MAL). Three samples collected from heavily poultry-manured soil contained Cd higher than the MAL. Samples collected from sale outlets did not exceed the MAL for Ni but two exceeded the MAL for Cd and one for Pb. Trace metal contamination is not a major concern in O. syriacum produced in Lebanon. Only one mixture sample from a sale outlet was higher in Pb than the MAL and three samples from heavily manured fields exceeded the MAL for Cd.

Varying concentrations of soil chromium (VI) for the exploration of tolerance thresholds and phytoremediation potential of the oregano (Origanum vulgare).

Varying concentrations of soil Cr(VI) were used in order to explore the tolerance thresholds and phytoremediation potential of Greek oregano (Origanum vulgare), in a pot experiment conducted outdoors. Oregano exhibited a rather exceptional capacity to bioaccumulate Cr in both the aerial part (up to 1200 mg of total Cr kg-1 DM) and the root-reaching 4300 mg kg-1 DM when grown in soil [Cr(VI)] of 150-200 mg kg-1. Plant responses indicated that there was a threshold set at 100 mg Cr(VI) kg-1 in the soil, above which the following results were recorded: (i) a restriction of Cr translocation from below- to above-ground plant part, (ii) a raise of the soil-to-root Cr transfer, and (iii) the Cr(III) evolution from the reduction of Cr(VI) was significantly decelerated in the root and accelerated in the aerial part. Soil [Cr] that surpassed this threshold challenged plant tolerance, resulting in a dose-dependent reduction of growth and antioxidant phenolics pool. Nonetheless, the significant Cr uptake capacity at plant level accounted for the considerably short remediation time (i.e., 29 years at soil [Cr(VI)] of 150 mg kg-1) calculated according to these results. The overall performance of oregano indicated that phytoremediation would be feasible at sites with Cr contamination levels ranging within the above-defined thresholds.

Modulation of hexavalent chromium toxicity on Οriganum vulgare in an acidic soil amended with peat, lime, and zeolite.

Dynamics of chromate (Cr(VI)) in contaminated soils may be modulated by decreasing its phytoavailability via the addition of organic matter-rich amendments, which might accelerate Cr(VI) reduction to inert chromite (Cr(III)) or high-cation exchange capacity amendments. We studied Cr(VI) phytoavailability of oregano in a Cr(VI)-spiked acidic soil non-treated (S) and treated with peat (SP), lime (SL), and zeolite (SZ). The addition of Cr(VI) increased the concentrations of Cr(VI) and Cr(III) in soils and plants, especially in the lime-amended soil. The plant biomass decreased in the lime-amended soil compared to the un-spiked soil (control) due to decreased plant phosphorus concentrations and high Cr(VI) concentrations in root at that treatment. Oregano in the peat-amended soil exhibited significantly less toxic effects, due to the role of organic matter in reducing toxic Cr(VI) to Cr(III) and boosted plant vigour in this treatment. In the lime-amended soil, the parameters of soil Cr(VI), soil Cr(III), and root Cr(III) increased significantly compared to the non-amended soil, indicating that Cr(VI) reduction to Cr(III) was accelerated at high pH. Added zeolite failed to decreased Cr(VI) level to soil and plant. Oregano achieved a total uptake of Cr(III) and Cr(VI) of 0.275 mg in plant kg-1 soil in a pot in the non-amended soil. We conclude that peat as soil amendment might be considered as a suitable option for decreasing Cr(VI) toxicity in soil and plant, and that oregano as tolerant plant species has a certain potential to be used as a Cr accumulator.

Differential effects of copper nanoparticles/microparticles in agronomic and physiological parameters of oregano (Origanum vulgare).

The effects of metallic copper nanoparticles (nCu) in plants are not well understood. In this study, soil grown oregano (Origanum vulgare) was exposed for 60days to nCu and Cu microparticles (µCu) at 0-200mgCu/kg. At harvest, Cu accumulation, biomass production, nutrient composition, and Cu fractions in soil were measured. Except for µCu at 50mg/kg, both nCu and µCu increased root Cu (28.4-116.0%) and shoot Cu (83.0-163.0% and 225.4-652.5%, respectively), compared with control. Copper accumulation from µCu increased as the external µCu increased. nCu and µCu did not affect shoot length, malondialdehyde, or chlorophyll, but increased water content (6.9-12.5%) and reduced shoot biomass (21.6-58.5%), compared with control. In addition, at 50mg/kg, µCu decreased root biomass and length (48.6% and 20.5%, respectively) and water content (1.8% and 3.9% at 100 and 200mg/kg, respectively). All treatments modified root and shoot Ca, Fe, Mg, and Mn (p≤0.05). Additionally, all Cu treatments decreased starch (33.9-58.5%), total sugar (39.5-55.7%), and reducing sugar (13.6-33.9%) in leaves. Results showed that metallic Cu nanoparticles/microparticles affected agronomical and physiological parameters in oregano, which could impact human nutrition. However, smaller size particles do not necessarily imply greater toxicity.

Effect of jasmonic acid and yeast extract elicitation on low-molecular antioxidants and antioxidant activity of marjoram (Origanum majorana L.).

BACKGROUND: Elicitation, which is a way of inducing plant secondary metabolism, may be an effective method for improving the quality of plant food. The aim of this study was to determine how the application of jasmonic acid (as an abiotic elicitor) and yeast extract (as a biotic elicitor) influences the production of some bioactive compounds in marjoram and the antioxidant activity of this herb. METHODS: Elicitation with 0.01 µM and 1 µM jasmonic acid as well as 0.1% and 1% yeast extracts was used for improving the health-benefiting quality of marjoram. The study focused on the effects of eliciting the level of some phytochemicals and the antioxidant activity of marjoram. RESULTS: There were no significant differences in total phenolic content between the elicited and control plants. In turn, the elicitation with 0.1% and 1% yeast extracts caused 1.8- and 2.5-fold increases in the ascorbic acid content in marjoram leaves, respectively. Both biotic and abiotic elicitation resulted in elevation of chlorophyll content, but only the abiotic elicitor (jasmonic acid) caused a significant increase (by over 50%) in the carotenoid content of marjoram leaves. The antiradical activity of marjoram was increased by the abiotic and biotic elicitation, whereas only the abiotic elicitation resulted in improving the reducing power of this herb. CONCLUSIONS: In conclusion, biotic and abiotic elicitation could be an effective strategy for improving the level of some phytochemicals, as well as the antioxidant activity of marjoram. A particularly valuable finding obtained in this study is that natural elicitors e.g. yeast extract can be equally effective in elevating the content of some bioactive compounds in herbs e.g. marjoram as an abiotic one.

Extracción, caracterización y actividad antioxidante del aceite esencial de plectranthus amboinicus L / Extraction, characterization and antioxidant activity of essential oil from plectranthus amboinicus L

Objetivo: extraer, caracterizar y determinar la actividad antioxidante del aceite esencial de orégano francés (Plectranthus amboinicus L) cultivado en la zona norte del departamento de Bolívar, Colombia. Método: el aceite esencial se obtuvo por hidrodestilación e hidrodestilación asistida por radiación con microondas, a partir de las hojas; se determinó densidad relativa a 20 °C, índice de refracción; solubilidad de los aceites esenciales en etanol (70 por ciento v/v) y rotación óptica. La composición química se evaluó mediante cromatografía de gases/espectrómetro de masa. La actividad antioxidante fue determinada mediante las técnicas de actividad antiradicalaria por los métodos DPPH., ABTS .+, y ORAC. Resultados: los rendimientos oscilaron entre 0,05 y 0,78 por ciento, dependiendo del método de extracción utilizado. Los resultados de la prueba de actividad antioxidante mostro que los aceites esenciales de orégano francés (Plectranthus amboinicus L) obtenidos mediante ambos métodos de extracción tuvieron resultados promisorios; además, estos aceites presentaron altos contenidos de monoterpenos oxigenados con reconocida actividad antioxidante, como son el carvacrol y el timol. Conclusiones: El aceite esencial de orégano francés (Plectranthus amboinicus L) se considera como promisorio para diseñar productos magistrales con actividad antioxidante(AU)

Objectives: to extract, to characterize and to determine the antioxidant activity of the essential oil of French Oregano (Plectranthus amboinicus L) grown in the northern part of the Department of Bolívar, Colombia. Methods: essential oil was extracted by distillation and radiation microwave-assisted hydrodistillation, from the leaves; relative density at 20 °C, refractive index; solubility of the essential oils in ethanol (70 percent v/v) and optical rotation were determined. The chemical composition was assessed using gas chromatography/ mass spectrometer. The antioxidant activity was determined using the techniques of antiradical activity by the DPPH., ABTS.+ and ORAC methods. Results: yields ranged from 0.05 to 0.78 percent, depending on the extraction method used. The results of the test of antioxidant activity showed that the essential oils of French oregano (Plectranthus amboinicus L) obtained by both methods of extraction had promising results; in addition, these oils had high contents of ,oxygenated monoterpeneswith recognized antioxidant activity, such as carvacrol and thymol. Conclusions: the essential oil of French oregano (Plectranthus amboinicus L) is considered as promising to design products with antioxidant activity(AU)

Salt effect on phenolics and antioxidant activities of Tunisian and Canadian sweet marjoram (Origanum majorana L.) shoots.

BACKGROUND: Two varieties of Origanum majorana (Canadian and Tunisian) were evaluated for their phenolic, flavonoid and tannin contents, individual phenolic compounds and antioxidant activities under NaCl constraint. RESULTS: The results showed a significant variability in phenolic composition and antioxidant behavior between the two varieties under salt stress. The phenolic composition of methanolic extracts was determined by reversed-phase high-performance liquid chromatography. Amentoflavone was the predominant flavonoid compound; in addition, trans-2-hydrocinnamic acid became the major phenolic acid with salt treatment of the Tunisian variety. In the control, Canadian variety extract was characterized by high levels of gallic acid and amentoflavone. However, under 75 mmol L(-1) NaCl, gallic acid content doubled, whereas amentoflavone content was maintained in the Canadian variety. Stimulation of phenolic acid biosynthesis was observed in these two varieties under salt treatment despite the fact that shoots of the Tunisian variety showed higher antioxidant activities compared to those from the Canadian variety. Tunisian O. majorana might have developed tolerance to salinity and avoided tissue damage by activating enzymes involved in the galactosylation of quercetin into quercetin-3-galactoside and quercetin-3-rhamnoside. CONCLUSION: Our results confirmed the tolerance of Tunisian O. majorana plants.

Effect of lixiviated sediments affected with treated water on Selenastrum capricornutum, Printz and Origanum vulgare L.

Xochimilco is an area of Mexico City fulfilling important ecological functions. However, the water of the canal network in the lacustrine zone of Xochimilco is supplied by the water treatment plants of the city, implying a risk of accumulated contaminants in the sediments. This study reports the effect of lixiviates obtained from sediments collected in the canals of Xochimilco on the growth of the alga Selenastrum capricornutum and the angiosperm Origanum vulgare. Three factors were tested: (a) water source in terms of the effluent from the two water treatment plants (urban waste-water, located at Cerro de la Estrella (CE) and urban-rural waters at San Luis Tlaxialtemalco (SLT); (b) sampling season (January, dry season; May and September, rainy season; and (c) distances from the water discharge point in the Xochimilco's main canal (5200 and 1000 m for CE, and 0, 200 m for SLT). The chemical water properties analyzed were: pH, electrical conductivity, N-NO(3), N-NH(3), N(Total), P-PO(4) and P(Total). The alga was more sensitive to the contaminants than O. vulgare, showing growth inhibition of 93-100%. The effect of sampling season on the inhibition of algal growth was ordered as follows: September > May > January. Lixiviates obtained from sediment samples 200 and 1000 m from the main point of water discharge caused a higher algal growth inhibition than the samples obtained at the source point. Lixiviate promoted the growth of seedlings of O. vulgare.