Essential oil of oregano (Origanum vulgare L.) reduces infection and proliferation of Toxoplasma gondii in BeWo cells with induction of autophagy and death of tachyzoites through a mechanism similar to necrosis.

Toxoplasmosis poses a global health threat, ranging from asymptomatic cases to severe, potentially fatal manifestations, especially in immunocompromised individuals and congenital transmission. Prior research suggests that oregano essential oil (OEO) exhibits diverse biological effects, including antiparasitic activity against Toxoplasma gondii. Given concerns about current treatments, exploring new compounds is important. This study was to assess the toxicity of OEO on BeWo cells and T. gondii tachyzoites, as well as to evaluate its effectiveness in in vitro infection models and determine its direct action on free tachyzoites. OEO toxicity on BeWo cells and T. gondii tachyzoites was assessed by MTT and trypan blue methods, determining cytotoxic concentration (CC50), inhibitory concentration (IC50), and selectivity index (SI). Infection and proliferation indices were analyzed. Direct assessments of the parasite included reactive oxygen species (ROS) levels, mitochondrial membrane potential, necrosis, and apoptosis, as well as electron microscopy. Oregano oil exhibited low cytotoxicity on BeWo cells (CC50: 114.8 µg/mL ± 0.01) and reduced parasite viability (IC50 12.5 ± 0.06 µg/mL), demonstrating 9.18 times greater selectivity for parasites than BeWo cells. OEO treatment significantly decreased intracellular proliferation in infected cells by 84% after 24 h with 50 µg/mL. Mechanistic investigations revealed increased ROS levels, mitochondrial depolarization, and lipid droplet formation, linked to autophagy induction and plasma membrane permeabilization. These alterations, observed through electron microscopy, suggested a necrotic process confirmed by propidium iodide labeling. OEO treatment demonstrated anti-T. gondii action through cellular and metabolic change while maintaining low toxicity to trophoblastic cells.

Green manure (Crotalaria juncea L.) enhances Origanum vulgare L. biomass accumulation, essential oil yield, and phytochemical properties.

Green manure (GM) may reduce the use of chemical fertilizers, been an ecologically appropriate strategy to cultivation of medicinal plants. Crotalaria juncea, is one of the most used because it adapts to different climatic and high nitrogen content. Origanum vulgare. is widely used in cooking, pharmaceutical, cosmetic industries and food products. The objectives of this study were to evaluate the GM on biomass, essential oil (EO), phenolic and antioxidant. The experiment consisted: control; 150, 300, 450, and 600 g (Sh= leaves+steam) more 200 g roots (R); 600 g aerial part; 200 g roots; and soil with 300 g cattle manure per pot. The highest dry weights were observed in the presence of GM and cattle manure (90 days). The control had an EO production 75% lower in relation to the dose of 450 g GM (Sh+R). Principal component analysis showed that GM and cattle manure positively influenced the dry weight, content, yield, and EO constituents, and total flavonoids. The GM contributed to the accumulation of the major EO compounds (trans-sabinene hydrate, thymol, terpinen-4-ol). The GM management may be beneficial for cultivating, because it can increase the production of biomass and the active components, in addition to being an inexpensive resource.

Origanum Grosii Extracts as Novel Eco-Friendly Corrosion Inhibitors for Mild Steel In HCl Medium.

Two green inhibitors extracted from an endemic species (Origanum grosii (Og)) using two solvents of different polarity (water and ethanol), OgW (aqueous extract) and OgE (ethanolic extract), were used for the anticorrosion of mild steel (M steel) in a 1 M HCl medium. Anticorrosive performance of OgW and OgE was assessed using standard electrochemical techniques, EIS/PDP measurements, weight loss method and SEM/EDX surface analysis. The results show that OgW achieves a maximum inhibition efficiency of 92 % and that the extract in aqueous medium (more polar) is more efficient than the extract in ethanolic medium (less polar). Both extracts act as mixed inhibitors and their corrosion process is predominantly governed by a charge transfer. Concentration and temperature effect was studied and shown that they are two antagonistic parameters for the evolution of inhibitory effectiveness of both OgW and OgE. The adsorption isotherms of the two inhibitors OgE and OgW obey to the Langmuir adsorption model. Moreover, the examination of SEM images and EDX spectra support a deposit of both extracts on the metal surface by an adsorption phenomenon. Besides, theoretical approach of the molecular structures of the major compounds M-OgW and M-OgE and inhibition efficiency was examined via DFT calculations and molecular dynamics simulations and it was consistent with the experimental findings.

Chemical and Bioactive Evaluation of Essential Oils from Edible and Aromatic Mediterranean Lamiaceae Plants.

The Lamiaceae family, which includes several well-known aromatic plants, is scientifically relevant due to its essential oils (EOs). In this work, four EOs from Mediterranean species, namely Origanum vulgare L., Rosmarinus officinalis L., Salvia officinalis L., and Thymus vulgaris L., were evaluated for their volatile profiles and the biological activity in vitro to assess their potential use in the food and cosmetic sector. GC/MS analysis revealed dominant compounds, such as carvacrol, thymol, and eucalyptol. Regarding biological action, the samples exhibited antioxidant, cytotoxic, anti-inflammatory, antimicrobial, and antifungal activities, with O. vulgare and T. officinalis standing out. T. vulgaris showed the lowest EC50 in the reducing power assay, and O. vulgare had the lowest EC50 in the DPPH assay. Most EOs also displayed excellent anti-inflammatory responses and antifungal properties, with O. vulgare and T. vulgaris also demonstrating antibacterial activity. All EOs from Mediterranean species showed cytotoxicity against tumoral cell lines. Overall, the selected EOs stood out for their interesting bioactivities, with the obtained results underscoring their potential as natural preservatives and bioactive agents in various industrial applications, including food, pharmaceuticals, and cosmetics.

The impact of dietary oregano essential oil supplementation on fatty acid composition and lipid stability in eggs stored at room temperature.

*1. In many countries, eggs are not refrigerated and must be stored at room temperature. The objective of this study was to explore the effects of dietary oregano oil (275 mg/kg; ORE) versus an unsupplemented control diet (CON) on laying hens on the shelf life and fatty acid profile of eggs.2. Treatments were randomly distributed into 10 pens containing 27 birds each. A total of 200 eggs were collected from both groups on the same day and were stored for either 0, 10, 21 and 35 d. At each storage time, egg yolks were analysed for fatty acid profile and lipid peroxidation.3. The main indicator of lipid peroxidation, malondialdehyde (MDA), was significantly lower in ORE eggs compared to CON eggs (p = 0.001). Storage time had a significant impact on MDA concentrations (p = 0.023), with the highest found after 35 d. Significant differences were found for individual fatty acids, saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). Palmitic acid, stearic acid, oleic acid, linoleic acid and arachidonic acid were significantly lower in ORE eggs compared to CON eggs (p < 0.05). Palmitoleic acid (p = 0.002), linolenic acid (p = 0.001) and docosahexaenoic acid (DHA, p = 0.001) were significantly higher in ORE eggs.4. Storage only affected oleic, linolenic, linoleic, arachidonic and docosahexaenoic acids (p < 0.05). Total SFA, MUFA, n-6 and ratio of n-3 to n-6 (n-3:n-6) PUFA were significantly higher in CON eggs (p < 0.05). The ratio of SFA to PUFA (SFA:PUFA, p = 0.005) and total n-3 PUFA (p = 0.001) were significantly higher in ORE eggs.5. The n-3:n-6 ratio was significantly impacted by treatment (p = 0.021) and storage (p = 0.031) with no significant interaction. This ratio is important for human health indication and could lead to the development of designer eggs.

Modulatory effect of Origanum vulgare essential oil and carvacrol on Malassezia spp. virulence factors.

Malassezia sympodialis and Malassezia furfur are recognized as an important part of the human and animals healthy skin microbiota, but also as an opportunistic fungus due to their association with a broad spectrum of skin and systemic infections. Human skin infections associated with Malassezia spp. are often chronic, recurrent, and topical or oral azole treatments are challenging with not always successful outcomes. A wide inter and intraspecies antifungal susceptibility variability that may suggest a combination of wild-type strains and resistant mutants was reported. The essential oils are complex hydrophobic mixtures of different compounds extracted from plants by distillation and have demonstrated antimicrobial activity. In this study, toxicity in the larvae model and the ability of Origanum vulgare essential oil (OVEO) and carvacrol to inhibit virulence factors such as hydrophobicity, adherence, and biofilm formation of M. sympodialis and M. furfur was evaluated. We have demonstrated the antifungal activity of OVEO and carvacrol against both species. Carvacrol was more active and less toxic than OVEO at low concentrations (< 1 mg/ml). Malassezia sympodialis showed a significant decrease in adherence and its ability to form biofilms when OVEO or carvacrol is present. Both Malassezia species showed reduced hydrophobicity in the presence of carvacrol. Further studies will have to be carried out to understand how these substances act, but the inhibition of some virulence factors could represent a new target to overcome the problem of drug resistance.

The work reports the research on the effect of the Origanum vulgare essential oil and carvacrol, against virulence factors such as hydrophobicity, adherence, and biofilm formation of two species of Malassezia. The inhibition of virulence factors could represent a new target to overcome the drug resistance reported.

In Vitro and In Silico Evaluation of ACE2 and LOX Inhibitory Activity of Origanum Essential Oils and Carvacrol.

Origanum spp. are used both for culinary purposes and for their biological activities. In this study, commercial Origanum majorana, Origanum minutiflorum, Origanum vulgare, and Origanum onites essential oils and their prominent constituent carvacrol were evaluated for their in vitro and in silico angiotensin-converting enzyme 2 and lipoxygenase enzyme inhibitory potentials. The essential oils were analysed by gas chromatography-flame ionisation detection and gas chromatography-mass spectrometry, where carvacrol was identified as the major component (62 - 81%), confirming the quality. In vitro enzyme inhibition assays were conducted both with the essential oils (20 µg/mL) and with carvacrol (5 µg/mL). The comparative values of angiotensin-converting enzyme 2 percent inhibition for O. majorana, O. minutiflorum, O. vulgare, and O. onites essential oils were determined as 85.5, 79.1, 74.3, and 42.8%, respectively. As a result of the enzyme assays, carvacrol showed 90.7% in vitro angiotensin-converting enzyme 2 inhibitory activity. The in vitro lipoxygenase inhibition of the essential oils (in the same order) was 89.4, 78.9, 81.1, and 73.5%, respectively, where carvacrol showed 74.8% inhibition. In addition, protein-ligand docking and interaction profiling was used to gain structural and mechanistic insights into the angiotensin-converting enzyme 2 and lipoxygenase inhibitory potentials of major Origanum essential oil constituents. The in silico findings agreed with the significant enzyme inhibition activity observed in vitro. Further in vivo studies are suggested to confirm the safety and efficacy of the oils.

Unravelling the Chemotaxonomic Identity of "White" and "Black" Oregano (Origanum vulgare) in Northern Greece.

The two types of oregano used by the inhabitants of the villages of Μount Belles (GR1260001), the "white" oregano with white flowers and "black" oregano with purple flowers, were studied. The two oregano types were collected from five localities along an altitudinal gradient from 217 m up to 1299 m. "White" oregano, was found in the three lowland regions (up to 752 m) where the Pannonian-Balkanic turkey oak-sessile oak forest habitat (code 91M0) dominates. The "black" oregano was collected from the two higher altitudes, at 1177 m and 1299 m, where the Asperulo-Fagetum beech forest habitat (9130) occurs. Measurements of the density and size of peltate glandular hairs (sessile glands) on calyces, bracts, and leaves suggest that "white" oregano is distinguished by its conspicuous - apparently larger - glands. These differences were reflected in the total essential oil content, with the "white" oregano being much richer (up to 4.3 mL/100 g dry weight) than the "black" (up to 0.6%). Striking differences have also been found in the volatile fraction of their essential oil composition. The "white" oregano oils were characterized by the high content of carvacrol (up to 92.6% of identified peaks, by Headspace GC-MS). On the other hand, the two "black" oregano oils have a different aromatic profile, first reported from Greece, with main components including the sesquiterpenes ß-caryophyllene, D-germacrene, δ-cadinene and ß-bisabolene. The results so far indicate that "white" and "black" oregano, Origanum vulgare subsp. hirtum and subsp. vulgare respectively, can be clearly distinguished either by their morphological (glandular) differences or by chemical (essential oil) composition.

Antiproliferative Effect of Essential Oil Obtained from Oregano (Lippia palmeri S. Watson) Leaves Grown in Hydroponics and LED Light.

Nowadays, light-emitting diodes (LED) provide an alternative source to sunlight with specific intensity and wavelength that promotes plant growth. The features offered by LED could also stimulate the production of secondary metabolites of pharmaceutical interest. This work analyzed the cultivation of oregano (Lippia palmeri S. Watson) in a floating root hydroponic system supplemented by full-spectrum LED artificial light. Growth indicators like height, diameter, number of shoots, and leaf length and width were measured. The essential oil (EO) composition from the leaves of wild and hydroponic conditions found thymol (41.8 %) as the main product for the former and carvacrol (47 %) in hydroponics. The antiproliferative activity of EOs on human colorectal cancer HCT-15 shows that 6.4 µg/ml for hydroponic and 7.4 µg/ml for the wild plant reduce more than 50 % the cell viability. Overall, this study indicates that hydroponic conditions and full spectrum LED modifies the composition of the EO of L. palmeri on compared with the wild plant, which effectively induces cell growth inhibition in human colorectal cancer.

Antimicrobial and Antibiofilm Efficacy and Mechanism of Oregano Essential Oil Against Shigella flexneri.

The aim of this study was to assess the antimicrobial activity of oregano essential oil (OEO) against Shigella flexneri and eradication efficacy of OEO on biofilm. The results showed that the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of OEO against S. flexneri were 0.02% (v/v) and 0.04% (v/v), respectively. OEO effectively killed S. flexneri in Luria-Bertani (LB) broth and contaminated minced pork (the initial population of S. flexneri was about 7.0 log CFU/mL or 7.2 log CFU/g), and after treatment with OEO at 2 MIC in LB broth or at 15 MIC in minced pork, the population of S. flexneri decreased to an undetectable level after 2 or 9 h, respectively. OEO increased intracellular reactive oxygen species concentration, destroyed cell membrane, changed cell morphology, decreased intracellular ATP concentration, caused cell membrane depolarization, and destroyed proteins or inhibited proteins synthesis of S. flexneri. In addition, OEO effectively eradicated the biofilm of S. flexneri by effectively inactivating S. flexneri in mature biofilm, destroying the three-dimensional structure, and reducing exopolysaccharide biomass of S. flexneri. In conclusion, OEO exerts its antimicrobial action effectively and also has a valid scavenging effect on the biofilm of S. flexneri. These findings suggest that OEO has the potential to be used as a natural antibacterial and antibiofilm material in the control of S. flexneri in meat product supply chain, thereby preventing meat-associated infections.

A GC-MS and LC-HRMS perspective on the chemotaxonomic investigation of the natural hybrid Origanum × lirium and its parents, O. vulgare subsp. hirtum and O. scabrum.

INTRODUCTION: The genus Origanum L. (Lamiaceae) is widespread in the Mediterranean region. However, approximately 75% of the species are only encountered in the eastern part. Out of these, a total of nine species (11 taxa) and three natural hybrids occur in Greece. Nevertheless, so far, there is no consensus regarding their precise botanical classification in the literature. In fact, the taxon Origanum × lirium has been proposed both as a separate species as well as natural hybrid between Origanum vulgare subsp. hirtum and Origanum scabrum. OBJECTIVES: In this scope, the aim of the current study is to shed light on the matter through the investigation of the chemical composition of both the essential oils and the polar extracts of the mentioned taxa, collected from different geographical regions of Greece. RESULTS: As it was demonstrated by both gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-high-resolution mass spectrometry (LC-HRMS) data, and highlighted by our comparative analysis, it can be stipulated that Origanum × lirium shares its chemotype to a large extent with its parent species concerning both volatile and polar constituents. Additionally, geographical origin conditions stood out as a key factor influencing their chemical composition. CONCLUSION: Altogether, the present work provides useful information on the chemical composition of the taxa under investigation, while our findings support the opinion that Origanum × lirium should be considered not as a separate species, but rather as a hybrid on the way to becoming a species.

µ-Raman Determination of Essential Oils' Constituents from Distillates and Leaf Glands of Origanum Plants.

A novel, inexpensive and simple experimental setup for collecting µ-Raman spectra of volatile liquids in very small quantities was developed. It takes advantage of capillary forces to detain minute volatile liquid volumes. Spectra of volatile and even scattering or absorbing media can be measured more effectively. The method is used to facilitate the collection of intensity-consistent Raman spectra from a series of reference compounds present in Origanum essential oils, in order to quantify their constituents by multiple linear regression. Wild grown Origanum plants, collected from five different regions in Greece and taxonomically identified as O. onites, O. vulgare subsp. hirtum and O. vulgare subsp. vulgare, were appropriately distilled to acquire their essential oils. Comparison of the Raman results with those from headspace gas chromatography-mass spectrometry (HS GC-MS) confirmed the successful relative quantification of the most abundant essential oil constituents, highlighting the similarities and differences of the three Origanum taxa examined. Finally, it is demonstrated that directly measuring the leaf peltate glandular hairs yields exploitable results to identify the main components of the essential oil they contain, underlining the potential of in situ (field or industry) measurements utilizing microscope-equipped portable Raman spectrometers.

Essential Oil Composition and Antioxidant Activity of Oregano and Marjoram as Affected by Different Light-Emitting Diodes.

Oregano and marjoram are important aromatic spices in the food industry, as well as medicinal plants with remarkable antioxidant properties. Despite their popularity, little is known about treatments that would influence the antioxidant capacity of essential oils. In this study, different spectra of LED light, namely blue, red, white, blue-red, and natural ambient light as a control, were applied to assess the essential oil content, composition, flavonoid, phenolic, and antioxidant capacity of oregano and marjoram. GC-MS analysis revealed thymol, terpinen-4-ol, sabinene, linalool, p-cymene, and γ-terpinene as the main compounds. In oregano, the thymol content ranged from 11.91% to 48.26%, while in marjoram it varied from 17.47% to 35.06% in different samples. In oregano and marjoram, the highest phenolic contents were in blue (61.26 mg of tannic acid E/g of DW) and in white (65.18 mg of TAE/g of DW) light, respectively, while blue-red illumination caused the highest increase in total flavonoids. The antioxidant activity of oregano and marjoram extract was evaluated using two food model systems, including DPPH and ß-carotene bleaching. The highest antioxidant capacity was obtained in control light in oregano and blue-red light in marjoram. The results provide information on how to improve the desired essential oil profile and antioxidant capacity of extracts for industrial producers.

Optimizing the Distillation of Greek Oregano-Do Process Parameters Affect Bioactive Aroma Constituents and In Vitro Antioxidant Activity?

The aim of the present work was to optimize the conditions of the distillation process at a pilot scale to maximize the yield of specific bioactive compounds of the essential oil of oregano cultivated in Greece, and subsequently to study the in vitro antioxidant activity of these oils. Steam distillation was conducted at an industrial distillery and a Face-Centered Composite (FCC) experimental design was applied by utilizing three distillation factors: time, steam pressure and temperature. Essential oil composition was determined by static headspace gas chromatography-mass spectrometry (HS-GC/MS). To obtain a comprehensive profile of the essential oils, instrumental parameters were optimized, including sample preparation, incubation conditions, sampling process, injection parameters, column thermal gradient and MS conditions. With the applied GC-MS method, more than 20 volatile compounds were identified in the headspace of the oregano essential oils and their relative percentages were recorded. Carvacrol was the most prominent constituent under all distillation conditions applied. Data processing revealed time as the main factor which most affected the yield. The Desired Space (DSc) was determined by conducting a three-dimensional response surface analysis of the independent and dependent variables, choosing yields of thymol and carvacrol as optimization criteria. The in vitro antioxidant activity of the essential oils of all samples was measured in terms of the interaction with the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) after 20 and 60 min. The most prominent essential oils at different distillation conditions were also tested as inhibitors of lipid peroxidation. Higher % values of carvacrol and thymol were correlated to higher antioxidant activity. Evaluating the impact of the distillation conditions on the in vitro results, it seems that lower pressure, less time and higher temperature are crucial for enhanced antioxidant activities.

Ultrasound-Assisted Extraction of Total Phenolic Compounds and Antioxidant Activity Evaluation from Oregano (Origanum vulgare ssp. hirtum) Using Response Surface Methodology and Identification of Specific Phenolic Compounds with HPLC-PDA and Q-TOF-MS/MS.

Oregano is native to the Mediterranean region and it has been reported to contain several phenolic compounds particularly flavonoids that have been related with multiple bioactivities towards certain diseases. Oregano is cultivated in the island of Lemnos where the climate promotes its growth and thus it could be further used in promoting local economy. The aim of the present study was to establish a methodology for the extraction of total phenolic content along with the antioxidant capacity of oregano by using response surface methodology. A Box-Behnken design was applied to optimize the extraction conditions with regard to the extraction time, temperature, and solvent mixture with the use of ultrasound-assisted extraction. For the optimized extracts, identification of the most abundant flavonoids (luteolin, kaempferol, and apigenin) was performed with an analytical HPLC-PDA and UPLC-Q-TOF MS methodology. The predicted optimal conditions of the statistical model were identified, and the predicted values confirmed. The linear factors evaluated, temperature, time, and ethanol concentration, all showed significant effect (p < 0.05), and the regression coefficient (R2) presented a good correlation between predicted and experimental data. Actual values under optimum conditions were 362.1 ± 1.8 and 108.6 ± 0.9 mg/g dry oregano with regard to total phenolic content and antioxidant activity based on 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay, respectively. Additionally, further antioxidant activities by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) (115.2 ± 1.2 mg/g dry oregano), Ferric Reducing Antioxidant Power (FRAP) (13.7 ± 0.8 mg/g dry oregano), and Cupric Reducing Antioxidant Capacity (CUPRAC) (1.2 ± 0.2 mg/g dry oregano) assays were performed for the optimized extract. The extract acquired under the optimum conditions contain an adequate quantity of phenolic compounds that could be used in the production of functional foods by food enrichment procedure.

Microbiological Studies on the Influence of Essential Oils from Several Origanum Species on Respiratory Pathogens.

Essential oils (EOs) with established and well-known activities against human pathogens might become new therapeutics in multidrug-resistant bacterial infections, including respiratory tract infections. The aim of this study was to evaluate the antimicrobial activity of EOs obtained from several samples of Origanum vulgare, O. syriacum, and O. majorana cultivated in Poland. EOs were analyzed by GC-MS and tested against four bacterial strains: Staphylococcus aureus (MRSA), Haemophilus influenzae, Haemophilus parainfluenzae, and Pseudomonas aeruginosa. Chemical analyses showed that the Eos were characterized by a high diversity in composition. Based on the chemical data, four chemotypes of Origanum EOs were confirmed. These were carvacrol, terpineol/sabinene hydrate, caryophyllene oxide, and thymol chemotypes. Thin-layer chromatography-bioautography confirmed the presence of biologically active antibacterial components in all tested EOs. The highest number of active spots were found among EOs with cis-sabinene hydrate as the major compound. On the other hand, the largest spots of inhibition were characteristic to EOs of the carvacrol chemotype. Minimal inhibitory concentrations (MICs) were evaluated for the most active EOs: O. vulgare 'Hirtum', O. vulgare 'Margarita', O. vulgare 'Hot & Spicy', O. majorana, and O. syriacum (I) and (II); it was shown that both Haemophilus strains were the most sensitive with an MIC value of 0.15 mg/mL for all EOs. O. majorana EO was also the most active in the MIC assay and had the highest inhibitory rate in the anti-biofilm assay against all strains. The most characteristic components present in this EO were the trans-sabinene hydrate and terpinen-4-ol. The strain with the least sensitivity was the MRSA with an MIC of 0.6 mg/mL for all EOs except for O. majorana, where the MIC value reached 0.3 mg/mL. Scanning electron microscopy performed on the Haemophilus influenzae and Haemophilus parainfluenzae biofilms showed a visible decrease in the appearance of bacterial clusters under the influence of O. majorana EO.

Can Origanum be a hope for cancer treatment? A review on the potential of Origanum species in preventing and treating cancers.

In this study, the potential of aromatic Origanum species belonging to Lamiaceae family to prevent and treat cancer was investigated. Since aromatic plants contain phytochemicals such as essential oils, phenolic acids, terpenoids, flavonoids, alkaloids, vitamins, enzymes and minerals with beneficial biological activities, they have become more interesting and important in medicine, pharmacy and industry. Publications/research between 1950 and 2022 were screened to investigate the effects of Origanum species on cancer, and the effects of their extracts and essential oils in cancer prevention and treatment. Essential phytochemicals found in plants provide efficacy in the prevention and treatment of many diseases. Besides, the essential oils found in these plant extracts are another reason that makes them important. Therefore, it is preferred in traditional medicine in the fight against many diseases as well as cancer. Essential oils of Origanum species mainly contain monoterpenes such as p-cymene, carvacrol, thymol and γ-terpinene. Since these compounds exhibit anticancer properties, Origanum species are becoming the plants of choice in the fight against cancer. In this context, Origanum majorana L. Origanum vulgare and Origanum munzurense are promising species, considering the composition of their extracts and essential oil.

Determination of chemical compositions and antibacterial effects of selected essential oils against human pathogenic strains.

Increasing the rates of drug resistant bacteria, having adverse effects and also high costs of antibiotics lead to essential oils (EOs) with antibacterial properties have gained importance. The present study was predicted to evaluate antibacterial activity of cinnamon, lavender, tea tree, lemon, coconut, oregano, mint, laurel and eucalyptus EOs alone and in combination. Chemical components of effective EOs were examined through gas chromatography/mass spectrometry (GC/MS). Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays were used to identify antibacterial effects of EOs against bacterial strains. The Fractional Inhibitory Concentration index (FICI) of the binary combinations of EOs was determined by checkerboard method. Carvacrol, linalool, linalyl acetate, 1,8-cineole, cinnamaldehyde, terpinen-4-ol and p-cymene were found main components of EOs. Oregano, cinnamon and tea tree EOs exhibited the strongest antibacterial activity with the MIC range between 0.03125-1.00% (v/v). Tea tree/lavender and cinnamon/lavender mixtures showed a synergistic effect against Streptococcus pyogenes and Streptococcus agalactiae. Oregano with tea tree and laurel exhibited a synergistic effect against Staphylococcus aureus. Oregano showed a synergistic effect when combined with cinnamon, lavender and tea tree against S.agalactiae. Our findings indicated that EOs either alone or in combination against pathogens should be preferred as potential antibacterial agents.

Unraveling the Biosynthesis of Carvacrol in Different Tissues of Origanum vulgare.

Origanum vulgare, belonging to the Lamiaceae family, is a principal culinary herb used worldwide which possesses great antioxidant and antibacterial properties corresponding to various volatile organic components (VOCs). However, the metabolite profiles and underlying biosynthesis mechanisms of elaborate tissues (stems, leaves, bracts, sepals, petals) of Origanum vulgare have seldom been reported. Here, solid-phase microextraction-gas chromatography/mass spectrometry results showed that Origanum vulgare 'Hot and Spicy' (O. vulgare 'HS') was extremely rich in carvacrol and had the tissue dependence characteristic. Moreover, a full-length transcriptome analysis revealed carvacrol biosynthesis and its tissue-specific expression patterns of 'upstream' MVA/MEP pathway genes and 'downstream' modifier genes of TPSs, CYPs, and SDRs. Furthermore, the systems biology method of modular organization analysis was applied to cluster 16,341 differently expressed genes into nine modules and to identify significant carvacrol- and peltate glandular trichome-correlated modules. In terms of these positive and negative modules, weighted gene co-expression network analysis results showed that carvacrol biosynthetic pathway genes are highly co-expressed with TF genes, such as ZIPs and bHLHs, indicating their involvement in regulating the biosynthesis of carvacrol. Our findings shed light on the tissue specificity of VOC accumulation in O. vulgare 'HS' and identified key candidate genes for carvacrol biosynthesis, which would allow metabolic engineering and breeding of Origanum cultivars.

Long-Term Refrigerated Storage of Beef Using an Active Edible Film Reinforced with Mesoporous Silica Nanoparticles Containing Oregano Essential Oil (Lippia graveolens Kunth).

Beef is a fundamental part of the human diet, but it is highly susceptible to microbiological and physicochemical deterioration which decrease its shelf life. This work aimed to formulate an active edible film (AEF) incorporated with amino-functionalized mesoporous silica nanoparticles (A-MSN) loaded with Mexican oregano (Lippia graveolens Kunth) essential oil (OEO) and to evaluate its effect as a coating on fresh beef quality during refrigerated storage. The AEF was based on amaranth protein isolate (API) and chitosan (CH) (4:1, w/w), to which OEO emulsified or encapsulated in A-MSN was added. The tensile strength (36.91 ± 1.37 MPa), Young's modulus (1354.80 ± 64.6 MPa), and elongation (4.71%) parameters of AEF made it comparable with synthetic films. The antimicrobial activity of AEF against E. coli O157:H7 was improved by adding 9% (w/w) encapsulated OEO, and interactions of glycerol and A-MSN with the polymeric matrix were observed by FT-IR spectroscopy. In fresh beef, after 42 days, AEF reduced the population growth (Log CFU/cm2, relative to uncoated fresh beef) of Brochothrix thermosphacta (5.5), Escherichia coli (3.5), Pseudomonas spp. (2.8), and aerobic mesophilic bacteria (6.8). After 21 days, odor acceptability of coated fresh beef was improved, thus, enlarging the shelf life of the beef and demonstrating the preservation capacity of this film.