Carvacrol Content Research Articles

Acrylamide Induced Oxidative Cellular Senescence in Embryonic Fibroblast Cell Line (NIH 3T3): A Protection by Carvacrol

Background: Stress-induced cellular senescence is a perpetual state of cell cycle arrest occurring in proliferating cells in response to stressful conditions. It is believed that oxidative stress plays a unique role in this process. As a reactive chemical compound that can induce oxidative stress, acrylamide is widely applied in several fields. Carvacrol is a liquid phenolic monoterpenoid found in essential oils of some plants and is known for its antioxidant and anticarcinogenic properties. Objectives: The current study aimed to evaluate the effects of carvacrol on oxidative stress and cellular senescence induced by acrylamide in the NIH 3T3 cell line. Methods: NIH 3T3 embryonic fibroblast cells were exposed to different concentrations of acrylamide, carvacrol, and H2O2 in a cell culture medium. The level of β-galactosidase (SA-β-gal) activity, as a marker of cellular senescence, was measured using staining and quantitative assays. Furthermore, to measure oxidative stress parameters, the content of glutathione and lipid peroxidation were determined. Results: Acrylamide could induce premature senescence evident by the elevated lipid peroxidation and SA-β-gal activity and declined cell viability and glutathione. Moreover, carvacrol showed beneficial effects on both acrylamide- and H2O2-induced cellular senescence by significantly reversing or subsiding the effect of oxidative stress and mediating its consequences. Conclusions: It can be concluded that carvacrol has protective effects against oxidative cellular senescence induced by acrylamide in the NIH 3T3 cell line.

Characterization and in vitro antimicrobial study of soy protein isolate films incorporating carvacrol

Soy protein, which is a by-product of soybean oil extraction, has been used as the carrier of essential oils in active packaging to inhibit the growth of spoilage microorganisms on food. In our study, the effects of incorporation of carvacrol in soy protein isolate (SPI) films on film characteristics, including mechanical properties, opacity, water vapor permeability (WVP), and antimicrobial activities, were evaluated. In addition, Fourier transform infrared (FTIR) spectroscopic characterization of the films was employed to examine the effects of the carvacrol on protein secondary structure and to study the release kinetics of carvacrol in the vapor phase. The results showed the mechanical properties, opacity and WVP of these SPI films were influenced by the concentrations of glycerol and carvacrol in the film-forming solution. The emulsified carvacrol acted as a plasticizer like glycerol to reduce resistance and rigidity of SPI films and increase their extensibility. In contrast, whereas films prepared with the higher concentrations of glycerol had significantly increased WVP, the effect of carvacrol concentration on WVP was not significant. FTIR spectroscopic analysis of protein secondary structure in the films revealed some transformation of β-sheet to α-helical structure with addition of carvacrol, consistent with a plasticizing effect. The release of carvacrol from films was monitored by gas-phase FTIR spectroscopy, and the release kinetics were well fit by a Weibull model. The results obtained by this FTIR methodology indicated that glycerol in the films promoted the release of carvacrol. Films prepared with ≥2% carvacrol exhibited high antimicrobial activities against Listeria grayi in vapor phase and could be employed in active packaging to improve the safety of food products.

Antifungal activity of Zataria multiflora Boiss. essential oils and changes in volatile compound composition under abiotic stress conditions

There is an increasing need for natural compounds for pest control and food preservation in agriculture, food and dairy industries. To satisfy this need, essential oils (EOs) from aromatic plants can serve as flavors, food preservatives and ecofriendly pesticides. This study investigated the potential of different EOs from field-collected leaves of fourteen Zataria multiflora Boiss. populations representing three different chemotypes (carvacrol, thymol and linalool) to inhibit a broad spectrum of fungal pathogens important in food industry and agriculture and the relationship between total leaf elements concentration and EOs compounds. Furthermore, a greenhouse experiment was performed to elucidate the effects of heat stress (33 °C vs. 20 °C), drought stress (50 % reduced irrigation), and ultraviolet light intensity (3, 6 and 9 W m−2 UV-A radiation) on the relative content of specific volatile compounds. The results indicated that low concentrations of carvacrol and thymol, but not of linalool chemotype EOs inhibit significantly the growth of pre- and postharvest pathogens Colletotrichum lindemuthianum, Fusarium sambucinum, Fusarium culmorum, Alternaria dauci and Botrytis cinerea (thymol/carvacrol EOs: 0.8−1 μL, linalool EOs: 4 μL). The analyses revealed further significant correlations between the concentrations of mineral elements in Z. multiflora leaves and relative amounts of EO compounds and antifungal activity. Abiotic stresses, particularly heat and the interaction of drought and heat, induced changes in plants of the linalool chemotype resulting in higher relative amounts of carvacrol (22.7 % and 32.9 % vs. 1.5 %), while drought stress alone did not influence the relative amount of the main volatile compounds of Z. multiflora (carvacrol 1.7 %). Furthermore, the relative amount of linalool was slightly reduced in the linalool chemotype, when plants were subjected to high intensities of UV-A radiation (33.9 % vs. 44.6 %), whilst the relative amount of carvacrol was slightly increased (20.1 % vs. 9%). Moreover, the main volatile compounds of plants from the carvacrol chemotype did not change in response to abiotic stresses. Understanding the effect of environmental conditions on aromatic plant populations and chemotype development helps agriculture and food industry fully exploiting the potential of aromatic plants as a source of natural sustainable fungicides or insecticides.

Determination of chemical component of essential oil of Origanum dubium plants grown at different altitudes and antifungal activity against Sclerotinia sclerotiorum

The aim of this study was to determine effect of altitude on the yields, composition, and antifungal activities of the essential oil isolated from Origanum dubium plant populations collected at four different altitudes. The essential oil yield, the content of four compounds and antifungal activities against Sclerotinia sclerotiorum were found to vary in relation to the different altitudes examined. According to the GC-MS analysis, carvacrol (46.51%–85.65%), linalool (0.24–48.37), p-cymene (1.89%–7.89%), and γ-terpinene (0.28%–6.31%) were determined as major compounds of essential oils of the plants collected from different altitudes. Altitude seems one of the factors that affected the quantity and quality of the essential oil of O. dubium. A significant correlation between the amount of carvacrol, p-cymene, and antifungal activities was determined. The essential oil of plant having the highest content of carvacrol (85.65%) showed the strongest antifungal activity against S. sclerotiorum at relatively very low concentration used (0.75 µl petri−1). Practical applications The essential oil yields, the chemical compositions and antifungal activities against Sclerotinia sclerotiorum were found to vary in relation to the altitudes where plants grown. Since the yield, chemical composition, and biological activities was affected, altitude seems to be an important factor that should be considered. To the best of our knowledge, this is the first study reporting antifungal activities of essential oil of Origanum dubium against devastating plant fungal disease agent S. sclerotiorum.

Improving quantity and quality of Thymus daenensis Celak. essential oil with application of Myco-Root biofertilizer under different irrigation levels

To determine the effects of Myco-Root biofertilizer and different irrigation levels on the content and essential oil compounds of thyme (Thymus daenensis Celak.), a factorial experiment was conducted in a completely randomized design with eight treatments and three replications in the greenhouse of Plant Production and Genetics department, Faculty of Agriculture, University of Maragheh, Iran, in 2020. The factors included drought stress at four levels of without stress (irrigation at field capacity (FC) as a control), mild (irrigation at 75% FC), moderate (irrigation at 55% FC), and severe (irrigation at 35% FC) stresses and biofertilizer at two levels of inoculation and non-inoculation with Myco-Root. The results demonstrated that the fresh and dry weight of leaves, stem dry weight, total dry weight, leaf relative water content, chlorophylls a and b and total chlorophyll content, and root colonization percentage decreased significantly with increasing the water deficit level. However, the carotenoid content and essential oil percentage showed an increasing trend with increasing drought stress. The highest carotenoid content and essential oil percentage was obtained by using Myco-Root under moderate drought stress. Thymol, carvacrol, p -cymene, 1,8-cineole, (E)-caryophyllene, borneol, γ-terpinene, and α-pinene were identified as the major constituents of essential oil in the all treatments. The highest content of thymol was obtained under mild drought stress with the Myco-Root application. Furthermore, the highest content of carvacrol was recorded under mild, moderate, and severe drought stresses, respectively with the Myco-Root application. On average, the application of Myco-Root biofertilizer increased the content of thymol, carvacrol, 1,8-cineole, E-caryophyllene, borneol, and α-pinene by 4.19, 48.28, 15.93, 16.33, 14.15, and 3.78%, respectively compared to not using this biofertilizer. Overall, the results showed that some morphological and physiological traits of thyme decreased significantly with increasing the water deficit levels, but the application of Myco-Root biofertilizer could amend drought stress and improve the growth, percentage and essential oil quality of the plant. Thus, the use of Myco-Root biofertilizer instead of chemical fertilizers could be recommended to achieve the sustainable agriculture in the thyme cultivation.

Antimicrobial Activity of Natural Plant Compound Carvacrol Against Soft Rot Disease Agent Dickeya zeae.

Dickeya zeae is a globally important bacterial pathogen that has been reported to cause severe soft rot diseases in several essential food crops, including bananas, rice, maize, and potatoes. Carvacrol, a hydrophobic terpene component, is found in aromatic plants of the Labiatae family and various essential oils. However, little work has been done on its antimicrobial potential against D. zeae. This study aimed to evaluate the antimicrobial activity and the functional mechanism of carvacrol against D. zeae. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of carvacrol against D. zeae were 0.1mg/mL and 0.2mg/mL, respectively. Carvacrol affected the cell membrane of D. zeae, as revealed by decreased intracellular ATP concentration, nucleic acid leakage, and decreased membrane potential. Scanning electron microscopy (SEM) micrographs confirmed that D. zeae cell membranes were damaged by carvacrol. Furthermore, a significant inhibition of D. zeae swimming motility and biofilm formation was observed following treatments with carvacrol at sub-inhibitory concentrations, indicating a significantly negative effect on these virulence factors. Accordingly, the tissue infection test revealed that carvacrol significantly reduced the pathogenicity of D. zeae. In a pot experiment, inoculated banana seedlings displayed remarkably lesser disease symptoms following treatment with carvacrol, and the control efficiency for banana soft rot was 32.0% at 14days post-inoculation. To summarize, carvacrol exhibits strong antimicrobial activity against D. zeae and great potential applications in the control of D. zeae-associated crop diseases.

Essential oil constituents and variations in antioxidant compounds of dried summer savory (Satureja hortensis cv. Saturn) affected by storage conditions and ammonium sulfate.

Considering the importance of spice plants and their shelf life, as affected by various factors, the current study considered Summer savory plants (Satureja hortensis cv. Saturn) for evaluation under the application of different concentrations of ammonium sulfate (0, 40, 60, 80, and 100 kg/ha) as primary treatments. Based on the plant response, the control group and 100 kg/ha ammonium sulfate were selected as suitable treatments for storage experiments (i.e., storage at ambient, refrigerator, and freezer temperatures for 8 months). Based on the results, the highest percentage and yield of S. hortensis essential oil and biomass occurred in response to 100 kg ammonium sulfate, whereas the lowest amounts were observed in the control group (i.e., in the absence of ammonium sulfate). During the storage period, the essential oil content decreased, but the carvacrol content of the essential oil increased. During the different durations and conditions of storage, the stability of secondary metabolites varied. Essential oil, rosmarinic acid, and carvacrol contents maintained greater stability in plants treated with ammonium sulfate (100 kg/ha), compared with the control group during the storage period. It can be concluded that the preharvest application of ammonium sulfate on S. hortensis improved plant growth and quality indices at preharvest time, while also maintaining the stability of its active ingredients at the postharvest stage and storage time. It also led results to recommend storing Summer savory in the freezer to better preserve its secondary metabolites.

Determining optimum carvacrol treatment as a cardinal value of a secondary model

Predictive microbiology methods were used to study the effect of carvacrol on the bacterial resistance to antimicrobials. Our objective was to estimate the optimum dose of carvacrol at concentrations below its MIC value (Minimum Inhibitory Concentration). As a fluorescent marker, ethidium bromide (EtBr) was applied to Escherichia coli to acquire raw data. The accumulation of EtBr was measured by its fluorescence signal (Fs), in the unit of RFU (Relative Fluorescence Unit). The temporal change of the fluorescence values, at a constant concentration of carvacrol, was described by a saturation curve (primary model). The difference, within the observation interval, between the fitted initial and maximum fluorescent values was chosen as the primary parameter to be fitted in the secondary model: a convex, asymmetric, bi-linear function of the carvacrol concentration changing between 0 and 0.5 MIC. Its breakpoint is the optimum value of the carvacrol, a cardinal parameter of the secondary model, where the chosen primary parameter assumes its highest value. This optimum was estimated with high uncertainty for individual experiments, but F-test showed that, with appropriate experimental and numerical procedure, its existence and value can be claimed with confidence. Our results demonstrate that the estimation of the optimum of the secondary model can be robust even if the full secondary model is uncertain.

Antimicrobial and Mechanical Properties of Jackfruit Seed Starch-based Films Containing Carvacrol

The demand for the development of a biodegradable antimicrobial packaging system from food wastes continues to grow because of food safety issues and the negative environmental impact brought about by synthetic plastics. In this study, a jackfruit seed starch-carrageenan (JSS-CG) blend film containing carvacrol was prepared. The antimicrobial capacity of the films against Staphylococcus aureus BIOTECH 1582 was evaluated by disk diffusion assay. Results revealed that zones of inhibition increased with the increase in carvacrol concentration. The optimum concentration of carvacrol for inhibiting the growth of S. aureus was 10% with a zone of inhibition of 19.67 mm. Furthermore, the film effectively controlled the growth of S. aureus in cheese stored at 28 °C. The microbial count of cheese decreased with storage time. Log reductions of 0.24, 0.56 and 0.66 were recorded after 12, 24 and 36 h of storage, respectively. The film exhibited a tensile strength of 12.03 MPa and an elongation at break of 72.55% based on the mechanical test. This study suggests that JSS-CG film containing carvacrol has potential as a food packaging material with desirable antimicrobial and mechanical properties.

Modification of phytochemical production and antioxidant activity of Dracocephalum kotschyi cells by exposure to static magnetic field and magnetite nanoparticles

Dracocephlum kotschyi Boiss is a genus in Lamiaceae family and a medicinal herb native to Iran. The cell suspension cultures were treated by static magnetic field (SMF) and Fe3O4 magnetite nanoparticles (MNP) to understand the production yield of secondary metabolites. The treatment procedure was done by cultivating the cells either with 100 ppm MNP, SMFs, or simultaneous exposure to both MNP and SMFs. The SMF at 30 mT was uniformly applied to the cells either for 3 or 4 days with a 3 h per day or a 5 h per day intervals, respectively. The contents of phenolics and phytochemicals were then examined by high performance liquid chromatography and UV–Vis spectrophotometer. These treatments imposed oxidative stress and induced polyphenol oxidase and phenylalanine ammonia lyase, accompanied by enhanced production of phenolics, anthocyanins, flavonoids, and lignin. The highest membrane embrittlement and elicitation was found upon simultaneous application of the MNPs and SMFs, followed by the MNP and SMFs. The contents of naringin, rosmarinic acid, quercetin, thymol, carvacrol, apigenin, and rutin increased in the intracellular biomass of all treated cells and extracellular culture media. These findings propose the potential of these elicitors in simultaneous production and secretion of these phytochemicals into culture media.

Comparative Studies on Volatile Oil Components Derived from Integrated Processing Technology of Origin and Traditional Cutting Processing Technology of Moslae Herba and Their Effects on Rats With Lung-Yin Deficiency.

This study aimed to examine the components of the volatile oil derived from the integration processing technology of origin (IPTO) of Moslae Herba (MH) and their effects on the treatment of rats with Lung-Yin deficiency. IPTO was compared with the traditional cutting processing technology (TCPT) to provide a feasible basis. The chemical constituents of the volatile oil were identified by gas chromatography-mass spectrometry (GC-MS). The Lung-Yin deficiency model was established by subjecting the animals to smoke and administering them with thyroid tablet suspension. The rats were randomly divided into six groups: control, model, Tween-80, positive, IPTO, and TCPT. After 30 days of intragastric administration, the macroscopic signs of rats and pathological morphology of the lung tissues were observed by the hematoxylin and eosin (H & E) staining method. The positive expression of the tumor necrosis factor (TNF-α) was observed by an immunohistochemical method. The levels of cholesterol (CHO), albumin (ALB), total protein (TP), blood urea nitrogen (BUN), interleukin-1 (IL-1), interleukin-1beta (IL-1β), cyclic adenosine monophosphate (cAMP), and cyclic guanosine monophosphate (cGMP) were detected in the serum of rats. A total of 42 and 37 components were identified from the volatile oils of IPTO and TCPT, respectively. Among them, the contents of carvacrol and thymol were higher in IPTO. The volatile oil of MH derived from IPTO and TCPT could improve the general signs and autonomous activities of the rats with Lung-Yin deficiency; increase the contents of cGMP, TP, and ALB; and decrease the anal temperature of the rats, the contents of IL-1β, CHO, and BUN in serum, the ratio of cAMP to cGMP, and the average optical density of TNF-α in their lung tissues. The findings indicated that IPTO was more efficient than TCPT. Its therapeutic effect might be associated with the change in TNF-α expression; the increase in cGMP, TP, and ALB contents; and the decrease in IL-1β, CHO, and BUN levels, laying the foundation for the clinical development and application of MH.

Carvacrol: A Promising Environmentally Friendly Agent to Fight Seeds Damping-Off Diseases Induced by Fungal Species

Background: Gramineae damping-off disease is a growing problem worldwide, which affects a large range of seedlings in nurseries, glasshouses, gardens, crops, forests and untimely generates a heavy economic impact on the agriculture and related sectors. Objectives: The present study was conducted to evaluate the preventive potential of carvacrol on germination of Fusarium oxysporum, Neocosmospora solani, and Microdochium nivale spores as responsible agents for Lolium perenne seeds damping-off disease. Material and methods: Macrodilution method in agar medium, spore germination, spore destruction, and preventive treatment bioassays were used to achieve this goal. Results: The minimum inhibitory concentration (MIC) of carvacrol vs. tested strains existed in the range of 0.25–0.5 mg/mL. Carvacrol used in concentrations ranging from 0.2 to 0.4 mg/mL inhibited the germination of all fungal spores in a dose-dependent manner. Carvacrol showed a very strong sporicidal effect against all studied fungal strains, and this effect was well confirmed by microscopic observations. The percentage of growth inhibition was found to be strictly correlated to carvacrol dose up vs. all strains. Carvacrol increased the emergence of L. perenne seeds when compared to both uninfested and infested seeds. Conclusion: Based on the results obtained, carvacrol fulfills the requirement for being a natural alternative agent to fight Gramineae seedlings’ damping-off caused by fungal species without adverse effects on the plants.

Intraspecific divergence in phytochemical characteristics and drought tolerance of two carvacrol-rich Origanum vulgare subspecies: subsp. hirtum and subsp. gracile

Oregano, Origanum vulgare L., is a well-reputed medicinal herb used globally in cosmetics, food and pharmaceutical industries. Essential oil (EO) composition and productivity of oregano subspecies are highly affected by water deficit stress. Here, a two-year (2018 and 2019) greenhouse study was conducted to comparatively investigate the impact of water deficit stress on biochemical traits and EO profiles of two carvacrol-rich subspecies of O. vulgare (subsp. gracile and subsp. hirtum). The pot-grown plants were subjected to four water stress treatments based on field capacity (FC) method, i.e., control condition (100 % FC), mild stress (75 % FC), moderate stress (50 % FC) and severe stress (35 % FC). Overall, the EO content of subsp. hirtum (up to 3.25 % (v/w)) was higher than that of subsp. gracile (up to 1.92 % (v/w)). Compared with control, the EO contents increased by over 75 % under moderate water stress. Carvacrol was present in the EO profiles of both subspecies as the major component. Its highest content in the subsp. hirtum was achieved under mild water stress (i.e., 60 % (in 2018) and 68 % (in 2019)), whereas in the subsp. gracile, it was obtained under severe (55 % (in 2018)) and moderate (51 % (2019)) stresses. Overall, the subsp. hirtum showed higher dry weight, EO and carvacrol content than subsp. gracile. Furthermore, a significant positive correlation was observed among dry weight and EO content (r = 0.74, p < 0.01). On the other hand, there was a negative correlation between carvacrol and p-cymene content (r = −0.60, p < 0.01). Water stress treatments inevitably reduced fresh weight, dry weight, relative water content and total chlorophyll content in both subspecies. However, the maximum quantum yield of PSII (Fv/Fm), superoxide dismutase and ascorbate peroxidase activity, and also proline content was changed in a subspecies-specific manner. The results of the present study enabled selection of the subsp. hirtum as a desirable prototype for relevant cultivation and prospective breeding programs.

Antibiofilm activity of carvacrol against Listeria monocytogenes and Pseudomonas aeruginosa biofilm on MBEC™ biofilm device and polypropylene surface

Biofilm may influence bacterial susceptibility to traditional disinfectants but identifying effective natural disinfectants as alternatives remains a great challenge to researchers. The objective of this research was to examine antibiofilm activity of carvacrol against Pseudomonas aeruginosa and Listeria monocytogenes. It was found that different concentrations of carvacrol dramatically reduced the P. aeruginosa and L. monocytogenes biofilms developed on both the MBEC™ biofilm device and polypropylene surface. On the MBEC™ biofilm device, the biofilm reduction was 5.04 log CFU/peg at 0.06% carvacrol for P. aeruginosa, and 3.81 log CFU/peg at 0.12% carvacrol for L. monocytogenes. On the polypropylene surface, P. aeruginosa was reduced by 4.79 log CFU/cm2 at 0.06% carvacrol, and L. monocytogenes was reduced by 4.62 log CFU/cm2 at 0.12% carvacrol. Visual observations using advanced microscopy confirmed the biofilm reduction results for both bacteria. This study demonstrated that carvacrol has potential use as a natural compound to prevent P. aeruginosa and L. monocytogenes related contaminations of food contact surfaces. These findings suggest that carvacrol could be used to formulate new sanitizers able to inhibit P. aeruginosa and L. monocytogenes biofilms.

Transcriptomic analysis of the food spoilers Pseudomonas fluorescens reveals the antibiofilm of carvacrol by interference with intracellular signaling processes

Pseudomonas fluorescens as an important food spoilage organism, has strong biofilm forming-ability to resist common biocides, increasing persistence and contamination in the cold fresh food chain. This bacterial biofilm organization is regulated by luxI/luxR mediated quorum sensing (QS) signaling. Carvacrol with antimicrobial properties is well documented, however, the mechanisms of its antibiofilm activity targeting QS are still not well known. The aim of this study was to explore the inhibition of carvacrol on biofilm formation and spoilage potential of two P. fluorescens PFuk4 and PF07 strains, and their luxI mutants (ΔluxI). The minimum inhibitory concentration (MIC) of carvacrol against planktonic wild type (WT) strains and the corresponding ΔluxI was 1.6 and 1.4 mM, respectively, and maximum sublethal concentration (MSC) was 0.8 mM. The acyl-homoserine-lactones (AHLs) C4-HSL and C6-HSL, as major autoinducer molecules, were greatly decreased in PFuk4 and PF07 treated with 0.4 mM carvacrol, while those in the ΔluxI were almost abolished. Biofilm formation and exopolysaccharide production of the P. fluorescens WT and ΔluxI strains were significantly inhibited by carvacrol at the MSC, as well as the observed sparer and thinner biofilm structures. Bacterial cell swimming and swarming motilities were both decreased by carvacrol without affecting cell viability. Protease activity secreted by P. fluorescens was significantly reduced treated by MSC of carvacrol, in consistent with the repression of sensory attributes, especially in the WT strains. Transcriptomics profiling revealed that exposure to 0.4 mM carvacrol dramatically altered gene expression in P. fluorescens PF07 biofilm, as a total of 402 differentially expressed genes (DEGs) were upregulated and 308 DEGs were downregulated, compared with the untreated biofilms. Those DECs were mainly involved in pathways of ribosome, bacterial chemotaxis, citrate cycle. Furthermore, carvacrol also altered the transcription of P. fluorescens genes associated with flagellar assembly, chemotaxis, exopolysaccharide synthesis, signaling pathways of LuxR mediated QS and c-di-GMP, and amino acid degradation, which may contribute to biofilm development and spoilage potential. In addition, carvacrol was found to competitively bind with LuxR predicted protein to interrupt the interaction with C4-HSL, supported by molecular docking. Our results provide novel insights into the regulatory signaling networks of antibiofilm formation in P. fluorescens affected by carvacrol.

The effects of methylcellulose coating containing carvacrol or menthol on the physicochemical, mechanical, and antimicrobial activity of polyethylene films.

In this study, the physicochemical, mechanical, and antimicrobial activities of polyethylene (PE) films coated with peppermint (Menthol) and Origanum vulgare (Carvacrol) essential oil were evaluated. For this reason, PE films were coated with MC‐HPMC solution containing different concentrations of menthol and carvacrol (0, 1, 1.5, and 2%), and mechanical, electromagnetic, barrier, and antimicrobial properties of all prepared films were examined. The obtained results demonstrated that by increasing the concentration of menthol and carvacrol in film coatings, tensile strength (from 36 to 23 MPa), water vapor permeability (from 12 to 11 g.m‐1s‐1Pa‐1), and L* and b* indexes were decreased, while the oxygen permeability (OP) and elongation at break significantly were increased (p < .05). Increment of menthol and carvacrol concentration in PE film coating leads to an increase in the antimicrobial activity of films against Escherichia coli, Staphylococcus aureus, Listeria innocua, and Saccharomyces cervicea. Finally, the results obtained from this study demonstrated that PE film coated with high levels of carvacrol and menthol could be used as active antimicrobial packaging in the food packaging industry.

Carvacrol alleviates liver fibrosis by inhibiting TRPM7 and modulating the MAPK signaling pathway

Liver fibrosis is a compensatory response to the tissue repair process. The activation and proliferation of hepatic stellate cells (HSCs) are thought to be related to the occurrence of hepatic fibrosis. Therefore, inhibiting the activation and proliferation of HSCs is a key step in alleviating liver fibrosis. As a non-specific inhibitor of transient receptor potential melastatin 7 (TRPM7), carvacrol has anti-tumor, anti-inflammatory and anti-hepatic fibrosis activities. This study aimed to explore the protective effect of carvacrol on liver fibrosis and related molecular mechanisms. A CCl4-induced liver fibrosis mouse model and platelet-derived growth factor (PDGF-BB)-activated HSC-T6 cells (a rat hepatic stellate cell line) were employed for in vivo and in vitro experiments. C57BL/6J mice were orally administered different concentrations of carvacrol every day for 6 weeks during the development of CCl4-induced liver fibrosis. The results show that carvacrol could effectively reduce liver damage and the progression of liver fibrosis in mice, which are expressed as fibrotic markers levels were reduced and histopathological characteristics were improved. Moreover, carvacrol inhibited the proliferation and activation of HSC-T6 cells induced by PDGF-BB. In addition, it was found that carvacrol inhibits the expression of TRPM7 and mediated through mitogen-activated protein kinases (MAPK). Collectively, our study shows that carvacrol can reduce liver fibrosis by inhibiting the activation and proliferation of hepatic stellate cells, and the MAPK signaling pathway might be involved in this process.

Inhibition of growth and virulence of Vibrio cholerae by carvacrol, an essential oil component of Origanum spp.

In the age where bacterial resistance to conventional antibiotics is increasing at an alarming rate, the use of the traditional plant, herb extracts or other bioactive constituents is gradually becoming popular as an anti-virulence agent to treat pathogenic diseases. Carvacrol, a major essential oil fraction of Oregano, possesses a wide range of bioactivities. Therefore, we aimed to study the effect of sub-inhibitory concentrations of carvacrol on major virulence traits of Vibrio cholerae. We have used in vitro as well as ex vivo models to access the anti-pathogenic role of carvacrol. We found that the sub-inhibitory concentration of carvacrol significantly repressed bacterial mucin penetrating ability. Carvacrol also reduced the adherence and fluid accumulation in the rabbit ileal loop model. Reduction in virulence is associated with the downregulated expression of tcpA, ctxB, hlyA and toxT. Furthermore, carvacrol inhibits flagellar synthesis by downregulating the expression of flrC and most of the class III genes. Carvacrol exhibited anti-virulence activity against V. cholerae, which involved many events including the inhibition of mucin penetration, adhesion, reduced expression of virulence-associated genes culminating in reduced fluid accumulation. These findings indicate that carvacrol possesses inhibitory activity against V. cholerae pathogenesis and might be considered as a potential bio-active therapeutic alternative to combat cholera.

The effect of pore size on the diffusion of volatile antimicrobials is a key factor to preserve gelled foods

This study aimed to understand how the microstructure of gelled foods impacts the diffusion of a volatile antimicrobial compound and its efficacy at different depths from the surface. Carvacrol-loaded polylactic acid film was used to inhibit the growth of Pseudomonas fluorescens in WPI-carrageenan gels during storage at 4 °C. The diffusion of antimicrobials was increased in gels having larger average pore size. The antimicrobial efficacy of the antimicrobial packaging was dependent on the diffusion of carvacrol within the gels. The final concentration of carvacrol in the top layer was more than 4 fold higher than that in the middle layer and more than 13-fold higher than that in the bottom layer, resulting in a more effective inhibition in the top layer than those in the middle and bottom layers. Our study demonstrates the importance of considering the diffusion of antimicrobials in solid/semi-solid foods in the antimicrobial packaging design.

A comparative study on antibacterial activity of carvacrol and glutaraldehyde on Pseudomonas aeruginosa and Staphylococcus aureus isolates: an in vitro study.

The resistance of hospital bacterial isolates against traditional germicides, which used frequently, is one of the important factors contributing to emerging nosocomial infections. Moreover, due to having the side effects of chemical substances, the development of novel low-risk natural compounds seems necessary for control the spread of resistant pathogens in hospital environments. The aim of this study was to compare the effect of carvacrol and glutaraldehyde against two common hospital acquired pathogens, including Pseudomonas aeruginosa and Staphylococcus aureus. In this study 365 samples were collected from different wards of hospitals of Khorramabad, Iran. One hundred and sixty samples were identified as P. aeruginosa and S. aureus by using standard microbiological methods. Then the antibacterial effects of four combinations including carvacrol+ethanol, carvacrol+dimethyl sulfoxide (DMSO), glutaraldehyde 2%, and pure glutaraldehyde (50%) were evaluated and determined using dilution broth and disk diffusion methods. Our results showed that the carvacrol had more antibacterial effects against selected bacteria compared to glutaraldehyde. Moreover, the optimal time and concentration of carvacrol+ethanol against hospital isolates of P. aeruginosa and S. aureus was determined after 1h at concentration of 64μl/ml and 8μl/ml, respectively. In conclusion by comparing the results of carvacrol and glutaraldehyde, seem that carvacrol, as an herbal and natural agent, may be a suitable alternative to glutaraldehyde in hospital equipment's' sterilization.