Antimicrobial Activity Of Carvacrol Research Articles

Antimicrobial Activity of Carvacrol against Lactobacillus acidophilus and Lactobacillus casei, An In-Vitro Study

Antimicrobial Activity of Carvacrol against Lactobacillus acidophilus and Lactobacillus casei, An In-Vitro Study

IN VITRO ANTIMICROBIAL ACTIVITY OF CARVACROL AGAINST SHRIMP PATHOGENS AND ITS USE AS FEED ADDITIVE FOR THE PACIFIC WHITE SHRIMP

This study aimed to evaluate the in vitro effect of carvacrol on different microorganisms of importance in shrimp farming, as well as its in vivo effect on zootechnical, immunological and microbiological performance, as well as resistance, of Litopenaeus vannamei challenged with Vibrio parahaemolyticus. In particular, the antimicrobial activity of carvacrol was evaluated in vitro by analysis of the minimum inhibitory concentration (MIC) and by agar diffusion disc with Gram-negative and Gram-positive bacteria. The in vivo experiment was conducted using different concentrations of carvacrol (1, 3, 4 and 6 mg mL-1) added to shrimp feed, together with a control diet without carvacrol. After four weeks, zootechnical, immunological and microbiological parameters, as well as resistance, of animals challenged with V. parahaemolyticus were evaluated. The MIC of Vibrio alginolyticus and Vibrio harveyi was 0.078 mg mL-1, while for the other bacteria, it was 0.156 mg mL-1 of carvacrol. The greatest halos of inhibition were observed in V. parahaemolyticus and Vibrio harveyi with significant differences demonstrated for the other microorganisms, except Escherichia coli. The in vivo results showed no significant differences among treatments. In conclusion, the antimicrobial activity of carvacrol was confirmed with Gram-negative and Gram-positive bacteria, and it is suggested that its antimicrobial potential is more effective against Vibrio spp. However, the concentrations of carvacrol used in vivo did not affect the parameters evaluated.

Biodegradable Poly(lactic acid) Stabilized Nanoemulsions for the Treatment of Multidrug-Resistant Bacterial Biofilms.

Biofilm infections caused by multidrug-resistant (MDR) bacteria are an urgent global health threat. Incorporation of natural essential oils into biodegradable oil-in-water cross-linked polymeric nanoemulsions (X-NEs) provides effective eradication of MDR bacterial biofilms. The X-NE platform combines the degradability of functionalized poly(lactic acid) polymers with the antimicrobial activity of carvacrol (from oregano oil). These X-NEs exhibited effective penetration and killing of biofilms formed by pathogenic bacteria. Biofilm-fibroblast coculture models demonstrate that X-NEs selectively eliminate bacteria without harming mammalian cells, making them promising candidates for antibiofilm therapeutics.

Microencapsulation and antimicrobial activity of carvacrol in a pectin-alginate matrix

Carvacrol is a natural phenolic compound that has received great attention for its high antimicrobial activity. However, the applications of this compound are limited due to its high volatility and low water solubility. In this research, the use of food grade polymers for microencapsulation of carvacrol in a pectin-alginate matrix using a spray drying method was studied. The physical properties, encapsulation efficiency, stability, and the microstructure of the microcapsules were analyzed as well as the products’ antimicrobial and antioxidant properties.The microcapsules were regularly spherical particles with 4.51% moisture content, 0.33 g cm−3 bulk density, 4.55 min wettability, and a hygroscopicity of 34.44 g 100 g−1. The microcapsules also showed high encapsulation efficiency (76.98%) and stability. The microencapsulation process did not significantly affect the antimicrobial activity against Escherichia coli K12 (minimum inhibitory concentration (MIC) = 0.25 mg mL−1) and antioxidant activity (DPPH percentage inhibition (PI) = 89.96%) of carvacrol. The results indicated that the carvacrol microcapsule product can potentially be used as a controlled-release decontaminator in food and nutraceutical processing industries.

Pharmacokinetic and antimicrobial activity of a new carvacrol-based product against a human pathogen, Campylobacter jejuni.

In vitro and invivo studies were conducted to test a new carvacrol-based product designed to delay the carvacrol release so that it could reach the caeca of broiler chickens in order to control Campylobacter jejuni. Antimicrobial activity of carvacrol, a constituent of oregano and thyme essential oil, has been demonstrated against C. jejuni invitro, and this compound was found beneficial for broiler growth. Here, we tested a new liquid formulation that did not change the antibacterial efficacy of carvacrol against C. jejuni invitro, as assessed by broth microdilution. The mode of action of carvacrol also remained unchanged as illustrated by electronic microscopy. A pharmacokinetic assay monitored carvacrol of the solid galenic formulation in the avian digestive tract and this showed that this compound was mainly found in the last part (caeca, large intestine) and in the droppings. Extremely low concentrations of free carvacrol were present in blood plasma, with larger amounts of carvacrol metabolites: carvacrol glucuronide and sulphate. A qPCR analysis showed that the solid galenic form of carvacrol added at 5kg per tonne of food (i.e. 9·5mg of carvacrol per kg of bodyweight per day) significantly decreased the C. jejuni caecal load by 1·5 log. The new liquid formulation was as effective as unformulated carvacrol invitro. In vivo the solid galenic form seems to delay the carvacrol release into the caeca and presented interesting results on C. jejuni load after 35days. Results suggested that this product could be promising to control Campylobacter contamination of broilers.

The in vitro effect of carvacrol, a food additive, on the pathogenicity of O157 and non-O157 Shiga-toxin producing Escherichia coli

Shiga toxin producing Escherichia coli (STEC) are important pathogens implicated in foodborne outbreaks and severe human infections. E. coli O157:H7 is the most common strain amongst STECs however non-O157 STECs have been connected with numerous outbreaks worldwide. The use of natural plant extracts to reduce the risk from foodborne pathogens is gaining increasing importance. Therefore, the aim of the study was to investigate the effect of carvacrol against O157, O26, O45, O103, O111, O121, O145 and O104 at different concentrations. Changes in membrane permeability, membrane integrity and intracellular ATP levels were determined to further elucidate the possible antimicrobial mechanism. The effect of carvacrol on the phenotypic expression of virulence in terms of adhesion to human intestinal cells was also studied. Carvacrol had potent antibacterial effect against all strains. Treatment with carvacrol at different concentrations significantly affected the cell membrane permeability and reduced intracellular ATP levels for all STECs. It was also shown that exposure of STECs to carvacrol at sub-inhibitory concentrations reduces adherence to intestinal cells. The data presented here offer further insight into the antimicrobial activity of carvacrol and show that it has the potential to be used as a natural food antimicrobial against clinically relevant STECs even at sub-inhibitory concentrations.

Enhanced antimicrobial activity of essential oil components immobilized on silica particles

The antimicrobial activity of essential oils components (EOCs) is well-known. However, their high volatility and powerful aroma limit their application in the formulation of a wide range of food products. In this context, the antimicrobial activity of carvacrol, eugenol, thymol and vanillin grafted onto the surface of three silica supports with different morphologies, textural properties and chemical reactivities (fumed silica, amorphous silica and MCM-41) was evaluated herein. Materials characterization revealed a good immobilization yield and all the devices showed a micro-scale particle size. Sensory evaluation revealed that sensory perception of EOCs decreases after covalent immobilization. Moreover, immobilization greatly enhanced the antimicrobial activity of the essential oil components against Listeria innocua and Escherichia coli compared to free components. The incorporation of EOCs immobilized on silica particles into pasteurized milk inoculated with L. innocua demonstrated their effectiveness not only for in vitro conditions, but also in a real food system.

β-Cyclodextrin-grafted TEMPO-oxidized cellulose nanofibers for sustained release of essential oil

The present investigation deals with the development and characterization of a new controlled release packaging system for food. Novel sustained system was developed by direct grafting of beta-cyclodextrin (βCD) on the carboxyl groups of TEMPO-oxidized cellulose nanofibers (TEMPO-CNF) in aqueous solution and without using any spacer. Carvacrol, an aromatic essential oil component, was then entrapped in the ensued CD-grafted TEMPO-CNF. Successful functionalization of TEMPO-CNF was confirmed by conductometric titration, Fourier Transform Infrared Spectroscopy, and gravimetric analyses. The βCD-grafted TEMPO-CNF films exhibited sustained release of carvacrol over 150 h before reaching the equilibrium in water. Antimicrobial activity of carvacrol against Bacillus subtilis was increased (or improved by 47 h) from 3 h when using TEMPO-CNF to around (or against) 50 h when using CD-grafted TEMPO-CNF. These promising results pave the way for the development of new bio-based controlled release packaging materials with efficient antibacterial activity.

Effect of emulsification on the antimicrobial activity of carvacrol

This work focuses on the emulsification of carvacrol for its incorporation into juices with the aim of retaining antimicrobial activity while enhancing the stability of the oil in aqueous systems. Carvacrol was emulsified (CA-E) using capsul® (1:2 emulsion) and its antimicrobial activity was determined on Escherichia coli and Lactobacillus plantarum. The combined effect of CA-E and pH reduction to 4.5 was assessed on different juices. The sensitivity of L. plantarum to carvacrol was not affected by emulsification, whereas E. coli presented higher minimal inhibitory concentrations. Combined treatments improved the effect: 0.5 µL/mL CA-E increased from 0.2 to 2.1 log reductions of E. coli. Carvacrol emulsion (1.0 µL/mL) successfully inactivated E. coli in apple and orange juices, attaining undetectable levels (<1 log CFU/mL). The efficacy of carvacrol emulsion was improved by acidification; therefore, its incorporation at low doses in acidic foods may be a useful alternative for multiple applications.

Effect of Carvacrol on &lt;i&gt;Salmonella&lt;/i&gt; Saintpaul Biofilms on Stainless Steel Surface

Purpose : To evaluate the effect of carvacrol against Salmonella saintpaul biofilms on stainless steel surface. Methods : The effect of carvacrol on planktonic cells of S saintpaul was evaluated by determining the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). The action of carvacrol on S. saintpaul biofilms on stainless steel surface was evaluated on established biofilm and on biofilm formation by counting the number of bacterial cells that adhered to the surface and by scanning electron microscopy. Results : The antimicrobial activity of carvacrol against planktonic cells of S. saintpaul was observed. The highest inhibitory effect of carvacrol was observed during biofilm formation at 78 and 117 µg ml -1 when S. saintpaul biofilms were reduced by 3 log cycles (p < 0.05). Conclusion : Carvacrol reduced the number of bacterial cells that adhered to stainless steel surface, making it a pot Salential compound for Salmonella saintpaul control. Keywords : Salmonella spp ., Biofilm, Carvacrol, Antimicrobial activity, Planktonic cells, Stainless steel

Antibacterial effects of carvacrol against Staphylococcus aureus and Escherichia coli O157:H7

The objective of this study was to investigate the antimicrobial effects of carvacrol (CV) against Staphylococcus aureus (S. aureus) and Escherichia coli O157:H7 (E. coli O157:H7) strains in milk. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of CV against S. aureus and E. coli O157:H7 were determined. In addition, bactericidal kinetics and antimicrobial activity of CV against the aforementioned pathogens in milk over a period of 2 weeks were investigated. CV exhibited antibacterial activity against both foodborne pathogens tested. The MIC and MBC of CV against S. aureus were 15.0 and 20 mg/mL, respectively, whereas those against E. coli O157:H7 were 16.0 and 32 mg/mL, respectively. In time-kill assays, CV at MBC reduced the number of S. aureus and E. coli O157:H7 in milk to undetectable levels within 24 hr. The antibacterial effects of CV persisted for 14 days without any loss of activity. Results of this study suggest that CV has a potential antibacterial activity against foodborne pathogens such as S. aureus and E. coli O157:H7 in milk.

Antifungal activity and mechanism of action of carvacrol and thymol against vineyard and wine spoilage yeasts

Antimicrobial activity of carvacrol and thymol against natural yeast flora of the grapes and yeasts known to cause wine spoilage was examined. Carvacrol and thymol exhibited comparable or better antifungal activity than potassium metabisulphite, commercially used wine preservative, against the natural yeast flora and spoilage yeasts. The antifungal activity for both the compounds was better at pH 3.5 than pH 6.5. Addition of carvacrol and thymol (64 mg/mL) in red wine resulted in inhibition of growth of the spoilage yeasts. Carvacrol and thymol exerted their antimicrobial action through membrane damage, leakage of cytoplasmic content and ergosterol depletion. In conclusion, carvacrol and thymol holds promise as a potential natural preservative for the control of wine spoilage.

Evaluation of Carvacrol for the Control of Escherichia coli O157 on Cattle Hide and Carcass Cuts

The antimicrobial activity of carvacrol against Escherichia coli O157 was assessed on cattle hide and beef carcass cuts. Carvacrol (0, 10, 20, and 30 mg/mL) was applied using a spray bottle to cattle hide and beef carcass cuts, inoculated with a cocktail of E. coli O157 (5-6 log(10) CFU/cm(2)) and left in contact for 10 min. Following treatment, hide and carcass cuts were sampled using a swab method, and E. coli O157 were enumerated by plate counts on selective media. Carvacrol (30 mg/mL) significantly (p < 0.05) reduced inoculated E. coli O157 (1.4 and 1.58 log(10) CFU/cm(2)) compared to the no wash and water wash (0 mg/mL) controls on both carcass cuts and hide respectively. This preliminary study shows that carvacrol has the potential to control E. coli O157 on bovine hide and carcass cuts, but further research with larger scale trials is needed.

Antimicrobial Activity of Carvacrol: Current Progress and Future Prospectives

During the last few years the scientific community has shown a considerable interest in the study of plant materials as sources of new compounds to be processed into antimicrobial agents. In this context, carvacrol, a monoterpenic phenol, has emerged for its wide spectrum activity extended to food spoilage or pathogenic fungi, yeast and bacteria as well as human, animal and plant pathogenic microorganisms including drug-resistant and biofilm forming microorganisms. The antibacterial activity of carvacrol has been attributed to its considerable effects on the structural and functional properties of cytoplasmatic membrane. The data reported in this review provide an overview of the published literature regarding the antimicrobial properties of carvacrol and the recent patents claimed in order to highlight its future applications as a new antimicrobial agent. These could concern either the natural preservation in the cosmetic and food industries or an alternative which supports the conventional antimicrobial protocols. Interestingly, carvacrol alone or associated with one or more synergistic products could be incorporated in different formulations for biomedical and food packaging applications. However, more detailed safety investigations and in vivo studies should be carried out so that this molecule could be used in the future.

Atomic force microscopy analysis shows surface structure changes in carvacrol-treated bacterial cells

Carvacrol is a major component in some essential oils such as oregano and thyme and its inhibitory effect on the growth of various microorganisms is well documented. However, the active mechanism of carvacrol, as well as that of other essential oil components, has not yet been fully established and has generally not been well investigated. In this study, the antimicrobial activity of carvacrol against some Gram-positive and Gram-negative food-related bacterial strains was preliminarily verified and the effect of carvacrol on their cell envelope was further investigated by atomic force microscopy analysis. The atomic force microscopy images of the cells treated with carvacrol 3.3 mM for 1 h were analyzed by anappropriate software in order to visualize the effect of the treatment and to determine the values of cell surface roughness and some biometric parameters (cell length and width). The results showed that all microorganisms tested were sensitive to carvacrol both in solid and liquid media. Furthermore, images of cells of all strains treated with carvacrol exhibited appreciable modifications, indicating a change in cell surface structure. Finally, both length and diameter of the microorganisms decreased after contact with carvacrol.

Inhibition of verocytotoxigenic Escherichia coli in model broth and rumen systems by carvacrol and thymol

The antimicrobial activities of thymol and carvacrol were assessed against a selection of verocytotoxigenic Escherichia coli (VTEC) strains ( n = 11) and other bacterial species and spoilage bacteria ( n = 7) using a model broth system. The effects of pH, temperature, water activity, sodium chloride concentrations, inoculum size and the presence of competing microflora on the activities of thymol and carvacrol against E. coli O157:H7 strain 380-94 were also determined. The minimum inhibitory and bactericidal concentrations (MIC and MBC, respectively) and numbers of surviving E. coli O157:H7 were determined following incubation. The mean numbers of VTEC surviving exposure to thymol or carvacrol at concentrations of ≥ 500 μg/ml were between 2.0 and 7.8 log cfu/ml less than the numbers in the corresponding controls. The susceptibility of E. coli O157:H7 to carvacrol or thymol was found to increase with decreasing storage temperature, water activity, pH and E. coli O157:H7 inoculum size. Sodium chloride (0.5–2.5%) and the presence of a microflora cocktail did not significantly ( p > 0.05) affect the antimicrobial activities of thymol or carvacrol against E. coli O157:H7. The antimicrobial activity of carvacrol against E. coli O157:H7 was also tested in a model rumen system. A MIC of 500 μg/ml carvacrol reduced E. coli O157:H7 inoculated at levels of 10 3 and 10 6 cfu/ml to undetectable levels in the system after 24 h incubation. This concentration of carvacrol significantly ( p < 0.05) decreased the total gas production and volatile fatty acid concentrations in the model rumen assay.

Antimicrobial Activity of Carvacrol toward Bacillus cereus on Rice

The antimicrobial activity of carvacrol, a compound present in the essential oil fraction of oreganum and thyme, toward the foodborne pathogen Bacillus cereus on rice was studied. Carvacrol showed a dose-related inhibition of growth of the pathogen. Concentrations of 0.15 mg/g and higher inhibited the growth and the extent of inhibition depended on the initial inoculum size. To decrease the input of carvacrol on the taste and flavor of the product, a combined treatment with the structure analog cymene was tested. Due to the smell and taste of carvacrol at high concentrations, carvacrol was combined with cymene, a natural antimicrobial compound with a similar structure. A synergistic effect was observed when 0.30 mg/g carvacrol was combined with 0.27 mg/g cymene. Finally it was demonstrated that a common taste enhancer like soya sauce also increased the antimicrobial action of carvacrol toward B. cereus. The antimicrobial activity of carvacrol with cymene or soya sauce was influenced by the addition of NaCl.