Marjoram Research Articles

Antibacterial Activity of Selected Essential Oils against Foodborne Pathogens and Their Application in Fresh Turkey Sausages.

Essential oils (EOs) isolated from different plant materials, namely Origanum majorana L., Satureja hortensis L., and Satureja montana L. (OMEO, SHEO, and SMEO, respectively), were used in fresh turkey sausage processing. The chemical composition and in vitro antimicrobial potential of selected EOs and their mixture were determined. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against foodborne pathogens (Escherichia coli, Salmonella Enteritidis, and Listeria monocytogenes) ranged in the interval of 0.44-7.1 µL/mL. Fresh turkey sausages were produced with EOs addition and marked as follows: TOMEO-0.150 µL/g OMEO; TSHEO-0.150 µL/g SHEO; TSMEO-0.150 µL/g SMEO; TEOM-0.050 µL/g OMEO, 0.050 µL/g SHEO and 0.050 µL/g SMEO, and control (C) (without EOs). Microbiological profile and biogenic amines content in fresh turkey sausages were recorded during storage. The selected EOs and their mixture efficiently reduced bacterial growth and biogenic amines formation and accumulation. The lowest Enterobacteriaceae count and total biogenic amine (BA) concentration were determined through treatment TSHEO. The results of this study show that selected EOs could be useful in fresh turkey sausage processing in order to improve safety and shelf-life.

Optimizing the Antimicrobial Synergism of Melaleuca alternifolia (Tea Tree) Essential Oil Combinations for Application against Respiratory Related Pathogens.

Antimicrobial research into the use of Melaleuca alternifolia essential oil has demonstrated broad-spectrum activity; however, much of the research published focuses on identifying the potential of this essential oil individually, rather than in combination for an enhanced antimicrobial effect. This study aimed to determine the antimicrobial activity of four essential oil combinations, all inclusive of M.alternifolia, against nine pathogens associated with the respiratory tract. The minimum inhibitory concentration assay was used to determine the antimicrobial activity of four essential oil combinations, M.alternifolia in combination with Cupressus sempervirens, Origanum majorana, Myrtus communis, and Origanum vulgare essential oils. The interactions between essential oil combinations were analyzed using isobolograms and SynergyFinder 2.0 software to visualize the synergistic potential at varied ratios. The antimicrobial activity of the different combinations of essential oils all demonstrated the ability to produce an enhanced antimicrobial effect compared to the essential oils when investigated independently. The findings of this study determined that isobolograms provide a more in-depth analysis of an essential oil combination interaction; however, the value of that interaction should be further quantified using computational modelling such as SynergyFinder. This study further supports the need for more studies where varied ratios of essential oils are investigated for antimicrobial potential.

Comparative antibacterial effects of ginger and marjoram extract versus conventional irrigants on mature Enterococcus faecalis biofilms: An in vitro study.

This study evaluated antibacterial effects of Ginger and Marjoram extract compared with Routine Intracanal Irrigants on Mature Enterococcus faecalis Biofilms. Sixty-six extracted human teeth, were randomly assigned to four groups 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), chloroform extract of marjoram (Origanum majorana), and oil extract of ginger (Zingiber officinale), and two positive and negative control groups (n=11). Samples were contaminated with E. faecalis, except the negative control group. Then the root canals were irrigated with solutions above, after which dental debris was collected from each tooth separately, followed by culturing on plates containing BHI agar. The bacterial counts were finally determined with a colony counting machine. No bacterial growth was detected in the NaOCl, CHX, and negative control groups. However, some bacterial growth was observed in the ginger and marjoram groups. All four solutions successfully eliminated E. faecalis biofilms compared to the positive control group. Significant difference in the median bacterial growth between the ginger and marjoram groups and the positive control group (P<0.001) has been shown. There was no significant difference in median bacterial growth between the ginger and marjoram groups (P=0.94). Chloroform extract of marjoram and oil extract of ginger were effective in eliminating 6-week-old biofilms of E. faecalis in vitro; however, their effect was not as favorable as CHX and NaOCl. These herbal extracts yielded promising results in the present study; therefore, they can be used as intracanal irrigants instead of chemical agents. Key words:Biofilm, Chlorhexidine, E. faecalis, Ginger, Marjoram, Sodium hypochlorite.

Origanum majorana L. extract effects on kidney tissue in STZ-induced DM rats

Origanum majorana L. extract effects on kidney tissue in STZ-induced DM rats

Designing ultra-stable linseed oil-in-water Mickering emulsions using whey protein isolate cold-set microgels containing marjoram aqueous extract: Effect of pH and extract on rheological, physical, and chemical properties

In this study, whey protein isolate (WPI) cold-set microgels containing marjoram (Origanum majorana) aqueous extract (MAE) were prepared at different pHs (4.0, 5.0, and 6.0). After characterization, the microgel dispersion was used to stabilize linseed oil-in-water Mickering emulsions (MEs). The resultant MEs were then characterized in terms of physicochemical and rheological properties under the effect of pH and MAE addition. The morphology, particle size, zeta potential, and interfacial tension of microgels were affected by pH and MAE. XRD patterns showed the amorphous structure. Microgel-stabilized MEs did not reveal any significant sign of instability under gravity during 6 months of storage. All MEs had dominant elastic character. Despite the lowest zeta potential values, MEs prepared at pH 4 showed the highest physical stability against gravity but the lowest centrifugal stability against oiling off, which indicated that both viscous and elastic components are required for MEs stability. This sample had the highest apparent viscosity and the strongest viscoelastic properties. Rheological data were best fitted with Herschel-Bulkley and Power Law models. An increase in pH and presence of MAE improved the oxidative stability of MEs. The results of this study showed that WPI microgels are appropriate candidate for long-term stabilization of linseed oil-in-water MEs. The presence of MAE is useful in designing special emulsions in which the aqueous phase is partially replaced by the aqueous extract of medicinal plants.

Ag-TiO2 nanocomposite catalyzed synthesis of pyrimido[5′,4′:5,6]pyrido[2,3-d]pyrimidines under sonication

An aqueous mediated green synthesis of fused heterocyclic scaffold pyrimido[5′,4′:5,6]pyrido[2,3- d ]pyrimidine has been reported via multi three component reaction of 1,3-dimethylbarbituric acid, substituted aromatic aldehydes and 6-amino-1,3-dimethylpyrimidine-2,4(1 H ,3 H )-dione under sonication using Ag-TiO 2 nanocomposites (NCs) as a heterogeneous catalyst. Nanocomposite Ag-TiO 2 reveal good catalytic efficiency in present multicomponent reaction as excellent yields of desire pyrimido[5′,4′:5,6]pyrido[2,3- d ]pyrimidines was obtained in shorter reaction time. The reaction proceeds with operational simplicity and two C C and one C N new bonds are formed in one-pot operation. To make the whole procedure sustainable the synthesis of applied heterogeneous catalyst Ag-TiO 2 NCs was also carried out using Origanum majorana aqueous leaf extract under ultrasound irradiations. The prepared Ag-TiO 2 NCs characterized by FT-IR, XRD, SEM and EDS analysis.

Cytotoxic, apoptotic, and necrotic effects of silver nanoparticles biosynthesized using Origanum majorana extract

application. Anticancer activity of Origanum majorana extract and silver nanoparticles was investigated by MTT assay using human pancreatic adenocarcinoma cell lines (Capan-1), mouse normal fibroblast cell lines (L929), and human colon adenocarcinoma cell line (Caco-2). AgNPs@Om exhibited the excellent cytotoxic effect on Capan-1 cell lines with the cell viability of 29.17% and 25.70%, 22.49%, 21.16% at 1.0, 0.5, 0.25, 0.125 μg/mL respectively. However, the extract was determined to show moderate activity. A considerable fall in the viable cell number in Caco-2 cell lines was observed after the treatment of AgNPs@Om. The viable cells of Caco-2 cell lines were detected as 32.0% at 1.0 μg/mL with the treatment of nanoparticles. Yet, the viable Caco-2 cells were determined as 48.2% with the treatment of O. majorana extract. Both extract and nanoparticles had no impact on the viability of non-tumor cells (L929). Moreover, nanoparticles induced apoptosis. Consequently, AgNPs@Om may be a promising anticancer drug candidate.

An Origanum majorana Leaf Diet Influences Myogenin Gene Expression, Performance, and Carcass Characteristics in Lambs.

Myogenin is a protein in the myogenic regulatory factor family that plays an important role in determining carcass and meat traits and is vital for the growth and development of livestock muscles. The objective of this study was to determine the impact of Origanum majorana leaf (MOL) on the myogenin gene expression of lambs. Twenty-four male Kermani lambs were used in a completely randomized design using two experimental groups (0% Origanum majorana L. = MOL0 and 4% Origanum majorana L. = MOL4). Final weight, average daily gain, hot and cold carcass weight, feed conversion ratio, empty body weight, hot and cold dressing percentage, the weight of the shoulder, loin, leg, and lean meat, and the lean/bone ratio were measured. A standard kit was used for extracting total RNA from the loin, leg, and shoulder muscles of the lambs’ tissues. The cDNA was synthesized, a real-time PCR was performed, and the obtained data were analyzed. The results of this study showed that the effect of MOL4 on dry matter intake is not significant. The MOL4 diet increased final weight by 8.22%, average daily gain by 28.57%, hot carcass weight by 11.38%, cold carcass weight by 13.43%, feed conversion ratio by 31.03%, empty body weight by 9.38%, hot dressing percentage by 2.92%, cold dressing percentage by 3.75%, shoulder weight by 56.70%, loin weight by 8.98%, leg weight by 10.90%, lean meat weight by 14.62%, and the lean/bone ratio by 2.85% (p < 0.05) compared to the MOL0. Along with adding MOL4 in the lambs’ diets, in comparison with MOL0, there was higher expression of myogenin in the loin (3.5 times), leg (3.9 times), and shoulder (3.6 times) muscles of the lambs. Due to the fact that adding Origanum majorana to the diet of the lambs enhanced the expression of the myogenin gene in the loin, leg, and shoulder muscles and increased parameters related to growth, it can be used to improve the parameters related to growth and to increase myogenin gene expression in the muscle of lambs.

Phytofabrication of Silver Nanoparticles and Their Potent Antifungal Activity against Phytopathogenic Fungi

Fungal plant pathogens cause huge losses in agricultural production by decreasing crop yield and quality. To reduce crop loss from fungal damage, various synthetic fungicides are applied indiscriminately in agricultural practice. The majority of synthetic fungicides are non-biodegradable, and several critical human health risks are associated with them. Green synthesis nanotechnology offers an effectual, cost-effective, ecofriendly, and innocuous method for the synthesis of green nanofungicides, an excellent replacement for synthetic chemical fungicides. Origanum majorana is an aromatic herb with immense pharmacological and medicinal properties. In this context, the present study used the leaves of O. majorana to synthesize silver nanoparticles. The biosynthesized particles showed an absorption peak at 441 nm with ultraviolet-visible spectrophotometry (UV-Vis). The spectra obtained from Fourier transform infrared spectroscopy (FT-IR) of O. majorana extract and AgNPs showed a myriad of functional groups corresponding to vital biomolecules that act as capping and reducing agents. The synthesized silver nanoparticles were spheroidal, and their size measured between 8 nm and 42 nm, as depicted by transmission electron microscopy (TEM). The energy-dispersive X-ray spectrum (EDX) showed a silver peak at 3 keV. The phytofabricated silver NPs demonstrated robust inhibitory activity on the mycelial growth of A. alternata f sp. lycopersici (87%), followed by Pestalotiopsis mangiferae (85%), Macrophomina phaseolina (78%), and Colletotrichum musae (75%). The minimum inhibitory concentration value for A. alternata. f sp. lycopersici and Pestalotiopsis mangiferae was 2 μg/mL, while the minimum fungicidal concentrations were 4 and 8 μg/mL, respectively. Additionally, the fabricated AgNPs induced severe damaging and destructive effects to the morphology of hyphae and conidia, as witnessed by scanning electron microscopy studies.

Origanum majorana Essential Oil-A Review of Its Chemical Profile and Pesticide Activity.

Origanum majorana is a medicinal and aromatic plant that belongs to the Lamiaceae family. It is cultivated in several parts of the world and, due to its splendid aroma and taste, is widely used for culinary purposes and in perfumes. The essential oil of the plant, to which is attributed its aroma, contains many secondary metabolites with valuable biological activity. One of them is the pesticide activity, which has attracted much interest. Given the necessity of replacing synthetic pesticides, essential oils are studied in an attempt to find naturally derived products. Thus, the aim of this review paper is to discuss the chemical profile of O. majorana essential oil and to present data regarding its insecticidal, repellent and fumigant activity. Data were collected from 1992 to 2022. Databases, including PubMed, Google Scholar, ScienceDirect and Scopus, were used for the research, and keywords, including O. majorana, sweet marjoram, essential oil, volatiles, pesticide, insecticide and repellent activity, were used. The results of this review paper indicate that O. majorana essential oil can be an alternative agent to manage pests. However, still, much research should be conducted to evaluate its toxicity against beneficial insects and to ensure its safety for human health.

Impacts of natural antioxidants on the fatty acid profiles of vacuum‐packaged tuna‐like muscles

SummaryThe impacts of natural preservatives such as olive leaf (Olea europaea L.) and sweet marjoram (Origanum majorana L.) extracts (OLE and SME) and cold storage on the fatty acid profiles of vacuum‐packaged tuna‐like muscles were evaluated. At the end of the storage time, the lowest content of the total saturated fatty acids (SFA) was observed in both ordinary and dark muscles of the treated samples (OLE and SME) whereas the highest content was found in their counterparts from the untreated samples (control). The total polyunsaturated fatty acid (PUFA) and total monounsaturated fatty acid (MUFA) contents decreased markedly in both ordinary and dark muscles of the control samples. In contrast, treated samples remained relatively stable throughout the storage time since the employment of plant extracts had protective effects against lipid oxidation and help maintain MUFA and PUFA levels in frigate tuna muscles. In addition, the PUFA/SFA ratio and polyene index which are considered important dietetic parameters showed that the used plant extracts (OLE and SME) did not result in a reduction in the PUFA/SFA ratio and prevented PUFA damage in both frigate tuna muscles during storage. Thus, the use of plant extracts such as OLE and SME can be recommended as natural preservatives for the fish processing industry.

Potential Role of ‘Green’ Synthesized Titanium Dioxide Nanoparticles in Photocatalytic Applications

Environmental sustainability is the cornerstone of the development of nanotechnology in today’s time. The synthesis of nanoparticles (NPs) based on green chemistry widely promotes this concept by minimizing the use of toxic precursors. Herein, the synthesis of titanium dioxide (TiO2) NPs is reported using Origanum majorana extract. The mode of synthesis is facile, eco-friendly, economically, applicable, and rapid. The constituent phytochemicals of the extract responsible for the formation of the nanocatalysts were identified using FTIR spectroscopy. In addition, X-ray diffraction, particle size measurements, and transmission electron microscopy were used to characterize the nanocatalysts. Moreover, the ability of TiO2 NPs to degrade rhodamine B dye under UV irradiation was also investigated. The key findings showed the marked photocatalytic property of the synthesized green TiO2 NPs, which could be potentially incorporated as a nanoscale technique in the process of water purification for human use.

Integration of NIR spectroscopy and chemometrics for authentication and quantitation of adulteration in sweet marjoram (Origanum majorana L.)

Origanum majorana L. (marjoram) has considerable promise as a folk remedy for digestive ailments in addition to its ethnomedicinal use in gynecological disorders. Due to the high demand for the botanical raw material, it is prone to intentional and inadvertent adulteration by morphologically similar herbs. In the current study, the adulteration of marjoram with its common adulterants; oregano, thyme, olive, basil and sage has been thoroughly investigated. To distinguish between marjoram and its prevalent adulterants, an integrated near infrared (NIR) spectroscopic method coupled with chemometric data analysis was developed. For exploratory pattern recognition, unsupervised multivariate models such as principal component analysis (PCA) and hierarchical cluster analysis (HCA) were implemented, followed by supervised models. Authentication of marjoram was successfully assessed using soft independent modelling of class analogy (SIMCA) with 100% sensitivity. Orthogonal projection to latent structures-discriminant analysis (OPLS-DA) modeling was employed to discriminate pure marjoram from its deliberately adulterated mixtures. Further, amounts of the adulterants were quantified in the botanical mixtures using partial least squares regression (PLS-R). The calibration and validation goodness of fit were determined to be greater than 0.9 and almost one, with a low root mean square error of prediction (RMSEP) and high ratio of performance to deviation (RPD) and range error ratio (RER) which highlight the model significant potential. Moreover, the optimal number of latent variables was found to be 5 as computed by permutation test. In the current study, the validity and reliability of the models employed to assess marjoram authenticity and purity was evidenced by both internal and external validation methods with a little to no data pre-processing.

Effects of Origanum majorana essential oil and antibiotics on the quality of frozen thawed Beni Arouss buck semen.

This study aims to investigate the effects of Origanum majorana (OM) essential oil (EO) at different concentrations and antibiotics on post-thawed Beni Arouss buck semen quality. Semen collection was performed using artificial vagina from eight Beni Arouss bucks. Ejaculates were pooled, divided into 12 equal aliquots, washed and diluted to 400 × 106 sperm/ml (with 7% of glycerol). Skim milk-based extender was supplemented with different concentrations of OM EO (0%; 0.01%; 0.02%; 0.03%; 0.04% and 0.05%) without antibiotics, marked as (CTR-), (M1-), (M2-), (M3-), (M4-) and (M5-), and with 50 mg of streptomycin and 50,000 IU of penicillin per 100 ml, marked as (CTR+), (M1+), (M2+), (M3+), (M4+) and (M5+), respectively. Aliquots were cooled to 4°C, then frozen in 0.25 ml straws with a programmable freezer and finally stored in liquid nitrogen for 48 h. Thawing was performed at 37°C for 30 s. Motility, live sperm, sperm abnormalities, membrane integrity, lipid peroxidation and bacterial growth were evaluated after thawing. Among the tested extenders, M2+ improved all semen quality parameters. Sperm motility, live sperm and membrane integrity increased significantly, while the number of abnormal sperm and bacterial growth decreased significantly. The toxic effect of OM EO, with and without antibiotics, appeared beyond 0.03%. In conclusion, M2+ is recommended to improve the cryopreservation of Beni Arouss buck semen.

Evaluating glufosinate-ammonium and flame weeding for weed control in sweet marjoram (Origanum majorana L.) cultivation

The objective of this four-year study was to compare the effects of flame weeding and spraying with glufosinate-ammonium on weed control in sweet marjoram field cultivation. The experiment was set up in a complete randomized four-replicate design with a plot area of 8 m2. Moreover, the content of essential oil in marjoram herb obtained from the control plants, as well as the composition of this oil were also studied. Marjoram emergence began 13–17 days after sowing, and it was very uneven and in some years it was extendend up to 5 weeks. Flaming (90 kg propane ∙ ha–1) was applied in two times: immediately after noticing the first marjoram emergence or 5 days later, while glufosinate-ammonium (600 g ∙ ha–1) was applied on the same date as the first flaming. The tested methods of weeding significantly reduced the number and fresh weight of weeds growing 3–4 weeks after the start of marjoram emergence, i.e. in the period of its greatest sensitivity to weed competition. They had no soil residual activity and their effect on weeds disappeared after the first weeding. Among weeds occurring in the experiment, only barnyardgrass (Echinochloa crus-galli (L.) P. Beauv.) was partially tolerant to flaming. Flaming applied at the second time did not increase the effectiveness of weed control, but significantly decreased the number of emergence and the yield of marjoram herb. Essential oil content in marjoram grated herb varied considerably depending on the year, ranging from 1.35 to 2.34%. The oil contained from 33 to 36 identified compounds, among which trans-sabinene hydrate (28–34%) and terpinen-4-ol (17–21%) were clearly dominant.

Green Synthesis of Zinc Oxide Nanocrystals Utilizing Origanum majorana Leaf Extract and Their Synergistic Patterns with Colistin against Multidrug-Resistant Bacterial Strains

There is a crucial necessity for the formulation of efficient antimicrobial agents owing to the increasing prevalence of hospital-acquired bacterial infections triggered by multidrug-resistant microbes that result in significant deaths and illnesses around the world. Hence, the current investigation examined the antibacterial proficiency of zinc oxide nanoparticles formulated utilizing the green route against bacterial strains that were resistant to multiple drugs. In addition, the synergistic antibacterial action of ZnO nanoparticles (ZnO NPs) combined with colistin was investigated against the tested microbial strains to determine the efficiency of the bioinspired ZnO nanoparticles in boosting the antibacterial proficiency of colistin antibiotic. Incidentally, the bioinspired ZnO nanoparticles were synthesized using water extract of Origanum majorana leaves and these nanomaterials were physicochemically characterized using different analytical techniques. The bioactivity of the synthesized nanomaterials against multidrug-resistant bacterial strains was appraised using the agar diffusion method. The biogenic ZnO NPs at a concentration of 100 μg/disk revealed a compelling antimicrobial efficacy against the tested strains, expressing the maximum antimicrobial action against Escherichia coli strain with clear zone diameter of 38.16 ± 0.18 mm. The remarkable antibacterial proficiency might be accredited to the tiny particle size of the bioformulated ZnO NPs of 12.467 ± 1.36 nm. The net charge of ZnO nanomaterials was −14.8 mV while XRD analysis confirmed their hexagonal wurtzite structure. Furthermore, the bioformulated ZnO NPs showed a promising synergistic potency with colistin demonstrating respective synergism proportions of 91.05, 79.07, 75.04, 75.25, 56.28 and 10.60% against E. coli, Klebsiella pneumoniae, Acinetobacter baumannii, Salmonella typhimurium, Enterobacter cloacae, and Pseudomonas aeruginosa, respectively. In conclusion, the water extract of O. majorana leaves mediated green formulation of zinc oxide nanoparticles with unique physicochemical characteristics and effective antibacterial proficiency against the examined drug-resistant bacterial strains. These nanomaterials could be used in the synthesis of effective antibacterial coatings to control hospital acquired infections caused by multidrug-resistant bacterial pathogens.

Phytotoxic Effects of Three Origanum Species Extracts and Essential Oil on Seed Germinations and Seedling Growths of Four Weed Species

The use of chemical pesticides to protect agricultural products is a global concern because of their adverse effects on the environment and public health. To avoid the dangers of synthetic herbicides, research has turned to natural alternatives. This study was conducted to evaluate the allelopathic effect of essential oil (EO) extracted from Origanum syriacum, Origanum onites, and Origanum majorana. In addition, the chemical composition of the essential oil was elucidated by gas chromatography and mass spectrometry (GC–MS) analysis. A total of 11 different components of O.syriacum were identified, and the main components were carvacrol (88.49), p-Cymene (5.71), γ-Terpinene (1.63), β-Caryoplhyllene (1.48), and Terpinen-4-ol (0.65), respectively. For O. onites, 10 different compounds were identified, and the main components were carvacrol (58.65), Thymol (30.97), Linalool (4.17), p-Cymene (1.94), and β-Caryoplhyllene (0.98), respectively. Finally, for O. majorana, 14 different compounds were identified, and the main components were carvacrol (40.57), α-Terpineol (29.28), p-Cymene (9.02), γ-Terpinene (5.80), and carvacrol methyl ether (3.46). Finally, 14 compounds from the Origanum majorana species were identified, with carvacrol (40.57), -Terpineol (29.28), p-Cymene (9.02), and -Terpinene (5.80) as the parent compound (3.46). Oxygenated monoterpenes were the highest in all species’ EO content. EOs and plant extracts were tested at 5, 10, and 20 L/Petri concentrations against seed germination and seedling growth in four weed species (Thlaspi arvense, Amaranthus retroflexus, Rumex cripus, and Lactuca serriola). The concentrations of essential oil were set as 5, 10, and 20 µL/Petri dishes for seed germination. In the greenhouse experiment, the final concentration of solutions was set as 20 µL and the solutions were directly sprayed on the surface of the weeds, and the mortality rates were noted after 24 and 48 h of application. It was observed that increasing the application decreased seed germination. The phytotoxic effects on the seedling germination in the greenhouse were observed, resulting in 48.76–94% mortality rates. Consequently, the essential oil from Origanum species could be considered as an alternative bio-herbicide to tested weeds.

GC-MS Profiling of Naturally Extracted Essential Oils: Antimicrobial and Beverage Preservative Actions.

The purpose of this study was to demonstrate the antimicrobial effects of natural essential oils (EO) and determine their preservative action. Eight natural essential oils were tested against Staphylococcus aureus, Escherichia coli, and Candida albicans representing gram positive, gram negative, and fungi, respectively. The plant materials were used in this study viz. Thymus vulgaris—thyme (TV), Mentha virdis (MV), Mentha longifolia (ML), Rosmarinus officinalis—rosemary (RO), Lavandula dentata—lavender (LD), Origanum majorana—oregano (OM), which belong to the Lamiaceae family. The other two plants were Cymbopogon citratus—lemon grass (family Poaceae) (CC), and Eucalyptus globulus (family Myrtaceae) (EG). Employing the disc diffusion susceptibility test, minimum inhibitory and minimum bactericidal concentrations were estimated for each oil, followed by the addition of oils to pasteurized apple juice after microbial induction. The results revealed that thyme oil showed the maximum zone of inhibition against all tested microbes enriched with monoterpenes class viz. eucalyptol (24.3%), thymol (17.4%), and γ-terpinene (15.2%). All other tested oils exhibited a concentration-dependent inhibition of growth and their MIC ranged from 0.1 to 100 µL/mL. The recorded minimum bactericidal concentration values were apparently double the minimum inhibitory concentration. The EO of Mentha virdis followed by Mentha longifolia showed maximum antimicrobial activity against the tested organisms in pasteurized apple juice. A gas chromatography–mass spectroscopy (GC–MS) analysis of lemon grass, thyme, and Mentha virdis essential oils showed their enrichment with monoterpenes class recording 97.10, 97.04, and 97.61%, respectively.

Role of antioxidant activity of essential oils in their acaricidal activities against Rhipicephalus annulatus.

Essential oils of Origanum majorana and Satureja thymbra as well as carvacrol are natural products that are known to have potent antioxidant activities. The current study was designed to investigate the role of the antioxidant properties of these natural products in their acaricidal activities against Rhipicephalus annulatus larvae. The synergistic and/or antagonistic effects of the addition of vitamins E and C and hydrogen peroxide (H2O2) to these natural products were also evaluated. Larval packet tests were used to evaluate the acaricidal activities against the larvae of R. annulatus. The antioxidant effectiveness of these products was determined by a DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay. The addition of vitamin E at 100mg/mL to O. majorana and S. thymbra decreased the concentrations required to achieve the death of half of the larvae (LC50) to 0.44 and 0.47%, respectively. The combination of O. majorana and S. thymbra attained the LC50 at 1.54% which was decreased to 0.69% after addition of vitamin E. Also, the addition of vitamin E to carvacrol reduced the LC50 to 0.27%. The total antioxidant activity of these natural products increased significantly in presence of vitamin E. The addition of H2O2 inhibited the acaricidal activity of all tested materials, especially at low concentrations. All treatments induced an increase in lipid peroxidation, whereas carvacrol-treated larvae revealed the lowest values for the superoxide dismutase. Glutathione peroxidase and catalase activity decreased in larvae treated with S. thymbra combined with vitamin E. In conclusion, the addition of vitamins E and C increased the acaricidal activities of the tested compounds, whereas the addition of H2O2 decreased these activities. The antioxidant activities of essential oils and their active components may play an important role in mediating their acaricidal activities.

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.