Encapsulation Of Carvacrol Research Articles

Encapsulation of carvacrol and thymol with yeast cell wall and its repellent activity against Amblyomma sculptum and Rhipicephalus sanguineus (Sensu Lato).

The main way to avoid contact with ticks and consequently tick-borne disease is the use of synthetic repellents. The search of new repellent compounds to increase the possibilities of use in strategies controls are necessary. The present study evaluated the repellent activity of two natural terpenes carvacrol and thymol in each one two different formulation (encapsulated and nonencapsulated with yeast cell wall) against the ticks Amblyomma sculptum and Rhipicephalus sanguineus sensu lato nymphs. Nymphs of A. sculptum and R. sanguineus s.l. of a single generation were used. The vertical filter paper repellency assay were performed with different concentration of both terpenes encapsulated and nonencapsulated in yeast cell wall. The repellent concentration 50% (RC50) were calculated to each compound formulation. Both carvacrol and thymol (encapsulated and nonencapsulated), had a repellent activity against A. sculptum and R. sanguineus s.l nymphs. Amblyomma sculptum was more sensitive to nonencapsulated carvacrol (RC50 values: 0.0032 to 0.0082mg/cm2 after 1 and 15min) (P < 0.05), while R. sanguineus s.l. was more sensitive to encapsulated carvacrol (RC50 values: 0.00008 to 0.0035mg/cm2 after 1 and 15min) (P < 0.05). Among tick species, R. sanguineus s.l. was more sensitive for most compounds than A. sculptum (P < 0.05). Although with distinct repellent activities, carvacrol and thymol encapsulated can be a promising alternative to synthetic repellents against A. sculptum and R. sanguineus s.l.

Carvacrol nanocapsules as a new antifungal strategy: Characterization and evaluation against fungi important for grape quality and to control the synthesis of ochratoxins

Fungi are a problem for viticulture as they can lead to deterioration of grapes and mycotoxins production. Despite the widespread use of synthetic fungicides to control fungi, their impact on the agricultural ecosystem and human health demand safer and eco-friendly alternatives. This study aimed to produce, characterize and assess the antifungal activity of carvacrol loaded in nanocapsules of Eudragit® and chia mucilage as strategy for controlling Botrytis cinerea, Aspergillus flavus, Aspergillus carbonarius, and Aspergillus niger. Eudragit® and chia mucilage were suitable wall materials, as both favored the encapsulation of carvacrol into nanometric diameter particles. Fourier Transform Infrared Spectroscopy (FTIR) analysis suggested a successful incorporation of carvacrol into both nanocapsules, which was confirmed by presenting a good encapsulation efficiency and loading capacity. Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) analyses revealed adequate thermal resistance. All fungi were sensible to carvacrol treatments and B. cinerea was the most sensitive compared to the Aspergillus species. Lower concentrations of encapsulated carvacrol than the unencapsulated form were required to inhibit fungi in the in vitro and grape assays. Additionally, lower levels of carvacrol (unencapsulated or encapsulated) were used to inhibit fungal growth and ochratoxin synthesis on undamaged grapes in comparison to those superficially damaged, highlighting the importance of management practices designed to preserve berry integrity during cultivation, storage or commercialization. When sublethal doses of carvacrol were used, the growth of A. niger and A. carbonarius was suppressed by at least 45 %, and ochratoxins were not found. The nanoencapsulation of carvacrol using Eudragit® and chia mucilage has proven to be an alternative to mitigate the problems with fungi and mycotoxins faced by the grape and wine sector.

Carvacrol Encapsulation in Chitosan-Carboxymethylcellulose-Alginate Nanocarriers for Postharvest Tomato Protection.

Advancements in polymer science and nanotechnology hold significant potential for addressing the increasing demands of food security, by enhancing the shelf life, barrier properties, and nutritional quality of harvested fruits and vegetables. In this context, biopolymer-based delivery systems present themselves as a promising strategy for encapsulating bioactive compounds, improving their absorption, stability, and functionality. This study provides an exploration of the synthesis, characterization, and postharvest protection applications of nanocarriers formed through the complexation of chitosan oligomers, carboxymethylcellulose, and alginate in a 2:2:1 molar ratio. This complexation process was facilitated by methacrylic anhydride and sodium tripolyphosphate as cross-linking agents. Characterization techniques employed include transmission electron microscopy, energy-dispersive X-ray spectroscopy, infrared spectroscopy, thermal analysis, and X-ray powder diffraction. The resulting hollow nanospheres, characterized by a monodisperse distribution and a mean diameter of 114 nm, exhibited efficient encapsulation of carvacrol, with a loading capacity of approximately 20%. Their suitability for phytopathogen control was assessed in vitro against three phytopathogens-Botrytis cinerea, Penicillium expansum, and Colletotrichum coccodes-revealing minimum inhibitory concentrations ranging from 23.3 to 31.3 μg·mL-1. This indicates a higher activity compared to non-encapsulated conventional fungicides. In ex situ tests for tomato (cv. 'Daniela') protection, higher doses (50-100 μg·mL-1, depending on the pathogen) were necessary to achieve high protection. Nevertheless, these doses remained practical for real-world applicability. The advantages of safety, coupled with the potential for a multi-target mode of action, further enhance the appeal of these nanocarriers.

Encapsulation of carvacrol and thymol for a persistent removal of Listeria innocua biofilms

Encapsulation of carvacrol and thymol for a persistent removal of Listeria innocua biofilms

Carvacrol-loaded nanoemulsions produced with a natural emulsifier for lettuce sanitization

Carvacrol is an antimicrobial agent that shows potential for eliminating microorganisms in vegetables, increasing food safety. However, intense odor and low water solubility of carvacrol are limiting factors for its application for fresh vegetables sanitization, which can be overcome by nanotechnology. Two different nanoemulsions containing carvacrol (11 mg/mL) were developed by probe sonication: carvacrol-saponin nanoemulsion (CNS) and carvacrol-polysorbate 80 nanoemulsion (CNP). Formulations presented appropriate droplet sizes (from 74.7 nm to 168.2 nm) and high carvacrol encapsulation efficiency (EE) (from 89.5 % to 91.5 %). CNS showed adequate droplet size distribution (PDI < 0.22) and high zeta potential values (around −30 mV) compared to CNP, with saponin chosen for the following experiments. Carvacrol nanoemulsions presented Bacterial Inactivation Concentration (BIC) against the Salmonella cocktail from 5.51 to 0.69 mg/mL and for the E. coli cocktail from 1.84 to 0.69 mg/mL. Among all tested nanoemulsions, CNS1 presented the lowest BIC (0.69 mg/mL) against both bacterial cocktails. Damage to bacterial cells in lettuce treated with nanoemulsion was confirmed by scanning electron microscopy. For lettuce sanitization, CNS1 showed a similar effect to unencapsulated carvacrol, with a high bacterial reduction (>3 log CFU/g) after lettuce immersion for 15 min at 2 × BIC. Using the same immersion time, the CNS1 (2 × BIC) demonstrated equal or better efficacy in reducing both tested bacterial cocktails (>3 log CFU/g) when compared to acetic acid (6.25 mg/mL), citric acid (25 mg/mL), and sodium hypochlorite solution (150 ppm). Lettuce immersed in CNS1 at both concentrations (BIC and 2 × BIC) did not change the color and texture of leaves, while the unencapsulated carvacrol at 2 × BIC darkened them and reduced their firmness. Consequently, carvacrol-saponin nanoemulsion (CNS1) proved to be a potential sanitizer for lettuce.

Carvacrol encapsulation into nanoparticles produced from chia and flaxseed mucilage: Characterization, stability and antimicrobial activity against Salmonella and Listeria monocytogenes

Carvacrol is a natural antimicrobial with excellent antimicrobial properties against several foodborne pathogens. Encapsulation can increase carvacrol stability and solubility, and mask its pronounced odor. Mucilages have been studied as wall material for nanoparticles due to their high retention capacity of bioactive compounds and ease of chemical modifications to improve their stability. In this study, 1.67 mg/mL of carvacrol encapsulated into chia mucilage nanoparticles (CMNP) and flaxseed mucilage nanoparticles (FMNP) were produced by high-energy emulsification technique and tested against Listeria monocytogenes and Salmonella. Encapsulation efficiency around 98% of carvacrol was obtained for both formulations. CMNP showed a diameter size of 179 nm and zeta potential of −11.4 mV. Bacterial Inactivation Concentration (BIC) of CMNP was 0.42 mg/mL against Salmonella and 0.83 mg/mL against L. monocytogenes. FMNP showed diameter size of 165.3 nm and zeta potential of −12.6 mV. BIC of FMNP was 0.83 mg/mL against both microorganisms. Scanning electron microscopy analysis showed that the nanoparticles are spherically shaped. Concentrations of BIC and ½ BIC were used to evaluate the kinetics of bacterial growth in the presence of antimicrobials (CMNP, FMNP and carvacrol solution). The results of this test showed that viable counts of Salmonella and L.monocytogenes were below the detection limit (1.69 log CFU/mL) after 2 h incubation (37 °C) using CMNP at the BIC. The wall material, rehydrated chia and flaxseed mucilages, reduced L. monocytogenes growth during 24 h. However, unloaded nanoparticles kept the viable counts of both microorganisms 2–5 log CFU/mL below the control curve of microbial growth during the 48 h experiment, suggesting that nanostructured mucilages potentiate antimicrobial properties. The results indicate that CMNP and FMNP have potential for use as food preservatives.

Zein–resin composite nanoparticles with coencapsulated carvacrol

This paper evaluated the potential of zein–resins nanoparticles to act as a carrier for water-insoluble oil carvacrol. The rosin and shellac were used as natural resins in different mass ratios to plant protein zein. Rosin is one of the natural gums. Shellac is a resinous secretion of the insect. The influence of nanoparticle composition on colloidal properties, encapsulation efficiency, and release of oil was studied. Zeta potential and size of thus prepared nanoparticles were studied. Carvacrol encapsulation efficiency and release were determined by the HPLC method developed for these compounds. Results showed that the resin type and share affect encapsulation efficiency and release of carvacrol. It was also shown that the addition of resins enhanced release from nanoparticles, compared to plain zein nanoparticles. Findings in the present work will help further understanding the interaction between alcohol–soluble biopolymers and provide new insight into the development of natural carriers for bioactive compounds. Novelty impact statement Natural polymers derived from food are considered desirable materials for constructing delivery systems to encapsulate, protect, and release bioactive components in nutraceuticals, pharmaceuticals, and food. Therefore, this paper is approached to fabricate the carvacrol-loaded zein/rosin (Z/R) and zein/shellac (Z/S) composite nanoparticles (NPs). Findings in the present work will help further understanding of the interaction between alcohol–soluble biopolymers (e.g., zein, rosin, and shellac) and provide new insight into the development of natural carriers for bioactive compounds.

Liposomal Encapsulation of Carvacrol to Obtain Active Poly (Vinyl Alcohol) Films.

Lecithins of different origins and compositions were used for the liposomal encapsulation of carvacrol within the framework of the development of active films for food packaging. Liposomes were incorporated into aqueous polymeric solutions from fully (F) and partially (P) hydrolysed Poly (vinyl alcohol) (PVA) to obtain the films by casting. The particle size distribution and ζ-potential of the liposomal suspensions, as well as their stability over time, were evaluated. Liposomal stability during film formation was analysed through the carvacrol retention in the dried film and the film microstructure. Subtle variations in the size distributions of liposomes from different lecithins were observed. However, the absolute values of the ζ-potential were higher (−52, −57 mV) for soy lecithin (SL) liposomes, followed by those of soy lecithin enriched with phosphatidylcholine (SL-PC) (−43, −50 mV) and sunflower lecithin (SFL) (−33, −38 mV). No significant changes in the liposomal properties were observed during the study period. Lyotropic mesomorphism of lipid associations and carvacrol leakage occurred to differing extents during the film drying step, depending on the membrane lipid composition and surface charge. Liposomes obtained with SL-PC were the most effective at maintaining the stability of carvacrol emulsion during film formation, which led to the greatest carvacrol retention in the films, whereas SFL gave rise to the least stable system and the highest carvacrol losses. P-PVA was less sensitive to the emulsion destabilisation due to its greater bonding capacity with carvacrol. Therefore, P-PVA with carvacrol-loaded SL-PC liposomes has great potential to produce active films for food packaging applications.

Effect of carvacrol encapsulation in starch‐based nanofibers: Thermal resistance and antioxidant and antimicrobial properties

The need for biodegradable and innovative nanomaterials in the food packaging industry motivates the conduction of studies on the production and characterization of new nanomaterials. The aim of this study was to evaluate the encapsulation efficiency (EE), thermal resistance, and antioxidant and antimicrobial activities of carvacrol encapsulated in potato starch nanofibers. The nanofibers possessed low EE (26%–33%) and high thermal resistance, showing residual carvacrol quantities after exposure to high temperatures. They also showed reduced but stable inhibition of DPPH oxidation compared with free carvacrol (20%, 33%, and 52% for the nanofibers with 20%, 30%, and 40% carvacrol, respectively) and OH inhibition varying from 4% to 18% for the nanofibers in general. Moderate antimicrobial activity (0.98 mg/ml) was found for all nanofibers throughout minimal inhibitory concentration (MIC) values. Our findings highlight the potential of starch/carvacrol nanofibers for application in the food sector as an antimicrobial and antioxidant agent. PRACTICAL APPLICATIONS: The nanomaterial developed in this study can be applied in the elaboration of active food packages, which can act as antioxidants and/or antimicrobial agents. The end use includes packages that undergo high temperatures in their production. In addition, the packages containing the starch/carvacrol nanofibers can preserve several types of food products.

Fabrication of pristine electrospun kafirin nanofiber mats loaded with thymol and carvacrol

In this project, we fabricated electrospun nanofiber mats from pristine kafirin, the storage protein of sorghum, for the first time which have the potential to be used as eco-friendly food packaging materials. The first novel step was kafirin extraction which showed that the purity of kafirin was higher in double-purification compared to single-purification, which led to high quality nanosized round, straight, unbroken and unentangled fibers. The electrospinning results indicate that binary solvent, 75% (v/v) acetic acid (AcOH) and 25% (v/v) butanol (BuOH) mixture, allows fabrication of homogenous nanofiber mats at 0.4 g/ml kafirin-to-solvent ratio, which is critical for to obtain good mechanical strength for the mats. Encapsulation of thymol and carvacrol was successful when the loading concentrations were 0.1 g/ml and 0.1–0.2 g/ml, for thymol and carvacrol, respectively. Loading of the fibers with the bioactives was confirmed with FTIR where the characteristic peaks for the bioactives appeared at 950 cm−1, 1150 cm−1, 1200 cm−1 and 1250 cm−1. Thymol or carvacrol encapsulation led to the conversion of some of the β-turn structures of kafirin into β-sheet structures. Surface hydrophilicity of loaded kafirin fiber mats decreased with increasing carvacrol concentration and increased with increasing thymol concentration.

Modified cyclodextrin type and dehydration methods exert a significant effect on the antimicrobial activity of encapsulated carvacrol and thymol.

The antimicrobial activity of essential oils and their constituents has led to increasing interest in using them as natural preservative agents. However, their high sensitivity to light and oxygen, their volatility and their low aqueous solubility are all obstacles to their application in the food, cosmetic or pharmaceutical industries. Encapsulation in cyclodextrins (CDs) is a solution for the application of such essential oils. The complexation of carvacrol and thymol with hydroxypropyl (HP)-α-, HP-β- and HP-γ-CD, the behavior of the solid complexes prepared by freeze-drying and spray-drying methods and the antibacterial activity of solid complexes were studied. Kc values of HP-α- and HP-γ-CD complexes with carvacrol (118.4 and 365.7L mol-1 ) and thymol (112.5 and 239.7L mol -1 ) were far lower than those observed for HP-β-CD complexes with carvacrol (2268.2L mol -1 ) and thymol (881.6L mol -1 ). The lower stability of HP-α- and HP-γ-CD complexes increased the release of compounds, thereby affecting the antimicrobial activity of carvacrol and thymol to a lesser extent than complexation with HP-β-CD, normally used in the encapsulation of carvacrol and thymol. HP-β-CD encapsulation of carvacrol and thymol markedly reduced their antimicrobial activity. The freeze-drying method barely affected the antimicrobial activity of carvacrol and thymol after encapsulation, while spray drying could be considered for the production of solid complexes in combination with the appropriate CD. It was thus demonstrated that HP-α- and HP-γ-CD are very suitable alternatives for the encapsulation of carvacrol and thymol with the purpose of preserving their bacteriostatic and bactericidal activities. © 2020 Society of Chemical Industry.

Encapsulation of carvacrol into ultrafine fibrous zein films via electrospinning for active packaging

Abstract In the present study, zein ultrafine fibers plasticized with tributyl citrate (TBC) were produced via electrospinning according to the central composite design with two independent variables, namely zein concentration (31.2-36.8%, w/v) and carvacrol level (0-8.2%, w/w). The changes in morphology, structure, encapsulation efficiency, thermal, mechanical and water vapor barrier properties of electrospun nanofibers with respect to the independent variables were investigated. The average diameter of zein fibers ranged between 103 ± 35 and 217 ± 47 nm. The encapsulation efficiency of carvacrol varied from 40 ± 1.9 to 81 ± 1.7%. Carvacrol loaded nanofibers had better thermal stability than zein fibers without carvacrol. Zein fibers with TBC exhibited higher tensile strength than those of pure zein fibers. The tensile strength of films was affected by the linear effect of both zein and carvacrol concentrations and interaction between them. Among fibrous films, a decreasing trend in WVP was observed with increasing carvacrol at low zein concentrations.

Antihypertensive effect of carvacrol is improved after incorporation in β-cyclodextrin as a drug delivery system.

Carvacrol (CARV), has been shown to possess various pharmacological properties, especially in the treatment of cardiovascular diseases. We evaluated the antihypertensive effect of the CARV free and encapsulation of CARV in β-cyclodextrin (CARV/β-CD), and whether CARV/β-CD is able to improve the antihypertensive effects of CARV free in spontaneously hypertensive rats (SHR). The rats were randomly divided into four groups, each treated daily for 21days and the mean arterial pressure and heart rate was measured every 5days: group 1, Wistar-vehicle solution; group 2, SHR-vehicle; group 3, SHR-CARV 50mg/kg/d; and group 4, CARV/β-CD 50mg/kg/d. After 21days of treatment, the mesenteric artery from treated animals was tested for phenylephrine (Phe) and sodium nitroprusside (SNP) sensitivity. In addition, administration of CARV/β-CD induced important antihypertensive activity when compared with the uncomplexed form, reducing the progression of arterial hypertension in SHR. Moreover, pharmacological potency to Phe in the SHR-CARV and CARV/β-CD groups was increased, approaching values expressed in the Wistar-vehicle. Furthermore, CARV/β-CD reduced the production of the pro-inflammatory mediator, IL-1β, and increased anti-inflammatory cytokine, IL-10. Together, these results produced evidence that the encapsulation of CARV in β-CD can improve cardiovascular activity, showing potential anti-inflammatory and antihypertensive effects.

Carvacrol loaded nanostructured lipid carriers as a promising parenteral formulation for leishmaniasis treatment

Leishmaniasis are a group of neglected infectious diseases caused by protozoa of the genus Leishmania with distinct presentations. The available leishmaniasis treatment options are either expensive and/or; cause adverse effects and some are ineffective for resistant Leishmania strains. Therefore, molecules derived from natural products as the monoterpene carvacrol, have attracted interest as promising anti-leishmania agents. However, the therapeutic use of carvacrol is limited due to its low aqueous solubility, rapid oxidation and volatilization. Thus, the development of nanostructured lipid carriers (NLCs) was proposed in the present study as a promising nanotechnology strategy to overcome these limitations and enable the use of carvacrol in leishmaniasis therapy. Carvacrol NLCs were obtained using a warm microemulsion method, and evaluated regarding the influence of lipid matrix and components concentration on the NLCs formation. NLCs were characterized by DSC and XRD as well. In addition, to the in vitro carvacrol release from NLCs, the in vitro cytotoxicity and leishmanicidal activity assays, and the in vivo pharmacokinetics evaluation of free and encapsulated carvacrol were performed. NLCs containing carvacrol were obtained successfully using a warm microemulsion dilution method. The NLCs formulation with the lowest particle size (98.42 ± 0.80 nm), narrowest size distribution (suitable for intravenous administration), and the highest encapsulation efficiency was produced by using beeswax as solid lipid (HLB=9) and 5% of lipids and surfactant. The in vitro release of carvacrol from NLCs was fitted to the Korsmeyer and Peppas, and Weibull models, demonstrating that the release mechanism is probably the Fickian diffusion type. Moreover, carvacrol encapsulation in NLCs provided a lower cytotoxicity in comparison to free carvacrol (p<0.05), increasing its in vitro leishmanicidal efficacy in the amastigote form. Finally, the in vivo pharmacokinetics of carvacrol after IV bolus administration suggests that this phenolic monoterpene undergoes enterohepatic circulation and therefore presented a long half-life (t1/2) and low clearance (Cl). In addition, C0, mean residence time (MRT) and Vdss of encapsulated carvacrol were higher than free carvacrol (p < 0.05), favoring a higher distribution of carvacrol in the target tissues. Thus, it is possible to conclude that the developed NLCs are a promising delivery system for leishmaniasis treatment.

Carvacrol encapsulation into nanostructures: Characterization and antimicrobial activity against foodborne pathogens adhered to stainless steel

Carvacrol is a natural antimicrobial capable of inhibiting several microorganisms. The encapsulation of this compound may increase its stability, water solubility and provide controlled release. In this study, carvacrol encapsulated into nanoliposomes (NLC) and polymeric Eudragit® nanocapsules (NCC) was tested against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli and Salmonella spp. adhered to stainless steel. NLC showed an average diameter of 270.8 nm, zeta potential of +8.64 mV, and encapsulation efficiency of 98%. Minimum Bactericidal Concentration (MBC) of NLC was 3.53 mg/mL against Salmonella and 5.30 mg/mL against the other bacteria. NCC presented an average diameter of 159.3 nm, zeta potential of +44.8 mV, and encapsulation efficiency of 97%. MBC of NCC was 4.42 mg/mL against E. coli and 3.31 mg/mL against the other bacteria. After 2 h incubation with NCC at carvacrol concentration equivalent to ½ MBC, viable counts of Salmonella and E. coli were below the detection limit (1.69 CFU/mL). The population of L. monocytogenes and S. aureus was reduced by 2 log CFU/mL in 6 h. Afterwards, pools of each bacterium were separately adhered to stainless steel coupons (initial population 6.5 CFU/cm2). Salmonella and E. coli were inhibited below the detection limit using the NCC at concentration equivalent to MBC, while L. monocytogenes and S. aureus were reduced by 4 log CFU/cm2 and 3.5 log CFU/cm2, respectively. Although free carvacrol presented better results than encapsulated one in all tests performed, using encapsulated carvacrol could be more interesting for food applications by masking the strong aroma of the compound, in addition to a controlled release of carvacrol. The results suggest that NCC have potential for use in food contact surfaces in order to avoid bacterial adhesion and subsequent biofilm formation.

Therapeutic Effect of Carvacrol-loaded Albumin Nanoparticles on Arthritic Rats.

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases. Carvacrol, an important natural terpenoid product in aromatic plants such as thyme, has shown anti-inflammatory effects in animal models of arthritis. However, its poor water solubility and high volatility have limited its application. In the present study in order to overcome this problem, we encapsulated carvacrol in the bovine serum albumin (BSA) nanoparticles and examined its therapeutic and immunomodulatory effects in adjuvant-induced arthritis (AIA). Carvacrol-loaded BSA nanoparticles were prepared by desolvation method. Nanoparticles had encapsulation efficiency (EE) of 67.7 ± 6.9% and loading capacity (LC) of 26.6 ± 2%. The size of particles was 148 ± 25 nm and they had monomodal distribution. After arthritis induction, the rats were treated intraperitoneally with nanoparticle for every 3 days until day 28. The treatment of the rats with 375 mg/mL carvacrol-loaded BSA nanoparticle significantly decreased clinical severity score (27.5 ± 9.8%, p = 0.008), erythrocyte sedimentation rate (33.4 ± 10%, p = 0.02), nitric oxide production (82.3 ± 2.6%, p = 0.004) and interleukin (IL)-17 gene expression (55.1 ± 8.2%, p = 0.003) compared to the untreated arthritic group. A higher reduction in inflammation severity in arthritic rats treated with carvacrol-loaded BSA in comparison to those treated with carvacrol alone was observed. In conclusion, encapsulation of carvacrol in nanoparticles reduced arthritis signs and release of NO and IL-17 inflammatory cytokine and therefore is suggested to be considered as a good approach for improving the therapeutic applications of carvacrol in RA.

Preparation of composite zein/natural resin nanoparticles

The aim of this work was to investigate a possibility of preparing composite zein/natural resin (shellac and rosin) nanoparticles by antisolvent co?precipitation from their aqueous ethanol solutions. Influence of zein/resin mass ratio (1/0, 0.8/0.2, 0.5/0.5, 0.4/0.6 and 0/1) and pH (2?12) on particle size, d, and zeta potential, ?, of the prepared particles was studied. The functional properties of zein/rosin composite nanoparticles were evaluated by studying carvacrol encapsulation. It was shown that the antisolvent precipitation can be successfully used to prepare the shellac and rosin nanoparticles, as well as the composite zein/shellac and the zein/rosin nanoparticles. Colloidal properties, d and ?, of the obtained nanoparticles are influenced by the zein/ /resin mass ratio and the pH of nanoparticles? dispersions. The isoelectric point of composite nanoparticles can be modulated by varying the zein/resin mass ratio. It was found that the zein/rosin nanoparticles are suitable for carvacrol encapsulation, where carvacrol release is enhanced by increasing the rosin share in the composite zein/rosin nanoparticles.

Enhancement in site-specific delivery of carvacrol for potential treatment of infected wounds using infection responsive nanoparticles loaded into dissolving microneedles: A proof of concept study

Chronic wound infections have become a challenging problem due to escalating antibiotic resistance and lack of viable delivery approaches. Carvacrol (CAR) has been reported to be effective against multidrug resistant pathogens. In this study, CAR was formulated into a site-specific nanoparticle (NP) delivery system using poly(caprolactone) (PCL) to achieve a sustained antimicrobial effect at infection sites. These NPs were further incorporated into dissolving microneedles (MNs) to facilitate painless application and overcome the necrotic tissue barrier which hinders drug penetration into wound bed. The release study exhibited significantly higher release of CAR from PCL NPs in the presence of bacteria, highlighting its potential for on-demand delivery. Moreover, encapsulation of CAR in PCL NPs resulted in 2–4 fold increase in its antimicrobial activity. Dermatokinetic studies revealed that CAR-PCL NPs-MNs were able to enhance skin retention of CAR after 24 h (83.8 ± 5.15%), compared to free CAR-MNs (7.3 ± 2.04%). Importantly, this novel approach exhibited effective antimicrobial activity in an ex-vivo wound model. Hence, these findings have proven the concept that loading of CAR into this advanced MNs platform can lead to sustained antimicrobial effect at desired site and may provide a novel effective approach for treatment of infected wounds. However, further studies must be conducted to investigate in-vivo efficacy of the developed system in an appropriate infection model.

Enhancement in Site-Specific Delivery of Carvacrol against Methicillin Resistant Staphylococcus aureus Induced Skin Infections Using Enzyme Responsive Nanoparticles: A Proof of Concept Study.

Methicillin resistant Staphylococcus aureus (MRSA) induced skin infections have become a challenging problem due to the escalating antibiotic resistance. Carvacrol (CAR) has been reported to be effective against MRSA. However, due to its characteristics, CAR exhibits low skin retention. In this study, CAR was formulated into site-specific nanoparticle (NPs) delivery system using poly(ε-caprolactone) (PCL), following incorporation into a hydrogel matrix to facilitate dermal delivery. The release study exhibited significantly higher release of CAR from PCL NPs in the presence of bacterial lipase, highlighting its potential for differential delivery. Moreover, encapsulation of CAR in PCL NPs resulted in a two-fold increase in its anti-MRSA activity. Dermatokinetic studies revealed that the NPs loaded hydrogel was able to enhance skin retention of CAR after 24 h (83.29 ± 3.15%), compared to free CAR-loaded hydrogel (0.85 ± 0.14%). Importantly, this novel approach exhibited effective antimicrobial activity in an ex-vivo skin infection model. Hence, these findings have proven the concept that the loading of CAR into a responsive NPs system can lead to sustained antimicrobial effect at the desired site, and may provide a novel effective approach for treatment of MRSA induced skin infections. However, further studies must be conducted to investigate in-vivo efficacy of the developed system in an appropriate infection model.

Effect of spray-drying temperature on physicochemical, antioxidant and antimicrobial properties of pectin/sodium alginate microencapsulated carvacrol

Microencapsulation has been extensively utilized in the pharmaceutical and food industries to entrap essential oils related to flavoring. Spray-drying is one of the most commonly used microencapsulation techniques in the food industry because of its low expense and readily available equipment. The spray-drying operating parameters, particularly inlet temperature, affect the physicochemical and functional properties of the microcapsules. In this research, four inlet air temperatures (100, 130, 160, and 190 °C) were applied for the encapsulation of carvacrol in a matrix composed of pectin/sodium alginate. The 100 °C treatment resulted in the highest moisture content, bulk density, and retention efficiency, but lowest dissolution time, hygroscopicity, and encapsulation efficiency. The antioxidant activity evaluated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay decreased, while the antimicrobial activity with respect to Escherichia coli K12 assessed by minimum inhibitory concentration (MIC) increased with the increasing inlet temperature due to the reduced retention efficiency. The microcapsules produced at lower temperature were smaller, smoother, and more spherical. Our results indicate that an inlet temperature between 100 and 130 °C is the ideal for processing pectin/sodium alginate encapsulated carvacrol.