Liposomal incorporation of carvacrol and thymol isolated from the essential oil of Origanum dictamnus L. and in vitro antimicrobial activity

Plant oils: From chemical composition to encapsulated form use

The last decade has witnessed a burgeoning global movement towards essential and vegetable oils in the food, agriculture, pharmaceutical, cosmetic, and textile industries thanks to their natural and safe status, broad acceptance by consumers, and versatile functional properties. However, efforts to develop new therapy or functional agents based on plant oils have met with challenges of limited stability and/or reduced efficacy. As a result, there has been increased research interest in the encapsulation of plant oils, whereby the nanocarriers serve as barrier between plant oils and the environment and control oil release leading to improved efficacy, reduced toxicity and enhanced patient compliance and convenience. In this review, special concern has been addressed to the encapsulation of essential and vegetable oils in three types of nanocarriers: polymeric nanoparticles, liposomes and solid lipid nanoparticles. First, the chemical composition of essential and vegetable oils was handled. Moreover, we gather together the research findings reported by the literature regarding the different techniques used to generate these nanocarriers with their significant findings. Finally, differences and similarities between these nanocarriers are discussed, along with current and future applications that are warranted by their structures and properties.

From bulk to nano-delivery of essential phytochemicals: recent progress and strategies for antibacterial resistance

Bacterial biofilms caused by antibiotic resistance are a severe cause of infection threatening human health nowadays. The primary causes of this emerging threat are poor penetration of conventional antibiotics and the growing number of varied strains of resistant bacteria. Recently, bulk phytochemical oils have been widely explored for their potential as antibacterial agents. However, due to their poor solubility, low stability, and highly volatile properties, essential oils are not effective for in vitro and in vivo antibacterial applications and require further preparation. In this review, we discuss the recent progress and strategies to overcome the drawbacks of bulk phytochemical oils using nano-delivery, as well as the current challenges and future outlook of these nano-delivery systems against bacterial resistance.

Essential Oils: Pharmaceutical Applications and Encapsulation Strategies into Lipid-Based Delivery Systems

Essential oils are being studied for more than 60 years, but a growing interest has emerged in the recent decades due to a desire for a rediscovery of natural remedies. Essential oils are known for millennia and, already in prehistoric times, they were used for medicinal and ritual purposes due to their therapeutic properties. Using a variety of methods refined over the centuries, essential oils are extracted from plant raw materials: the choice of the extraction method is decisive, since it determines the type, quantity, and stereochemical structure of the essential oil molecules. To these components belong all properties that make essential oils so interesting for pharmaceutical uses; the most investigated ones are antioxidant, anti-inflammatory, antimicrobial, wound-healing, and anxiolytic activities. However, the main limitations to their use are their hydrophobicity, instability, high volatility, and risk of toxicity. A successful strategy to overcome these limitations is the encapsulation within delivery systems, which enable the increase of essential oils bioavailability and improve their chemical stability, while reducing their volatility and toxicity. Among all the suitable platforms, our review focused on the lipid-based ones, in particular micro- and nanoemulsions, liposomes, solid lipid nanoparticles, and nanostructured lipid carriers.

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.

New perspective toward nutritional support for malnourished cancer patients: Role of lipids

To improve the difficulties related to malnutrition, nutritional support has become an essential part of multidisciplinary comprehensive treatment for cancer. Lipids are essential nutrient source for the human body, and nowadays in clinical practices, it has a positive interventional effect on patients suffering from cancer. However, contribution of lipids in nutritional support of cancer patients is still poorly understood. Moreover, the sensory and physicochemical properties of lipids can severely restrict their applications in lipid-rich formula foods. In this review article, for the first time, we have presented a summary of the existing studies which were related to the associations between different lipids and improved malnutrition in cancer patients and discussed possible mechanisms. Subsequently, we discussed the challenges and effective solutions during processing of lipids into formula foods. Further, by considering existing problems in current lipid nutritional support, we proposed a novel method for the treatment of malnutrition, including developing individualized lipid nutrition for different patients depending on the individual's genotype and enterotype. Nonetheless, this review study provides a new direction for future research on nutritional support and the development of lipid-rich formula foods for cancer patients, and probably will help to improve the efficacy of lipids in the treatment of cancer malnutrition.

Starch Edible Films/Coatings Added with Carvacrol and Thymol: In Vitro and In Vivo Evaluation against Colletotrichum gloeosporioides

The aim of this work was to evaluate the in vitro and in vivo effectiveness of thymol and carvacrol added to edible starch films and coatings against Colletotrichum gloeosporioides. In vitro evaluation consisted of determining minimal inhibitory concentration (MIC) of carvacrol and thymol was determined at different pH values against Colletotrichum gloeosporioides. With MIC values, binary mixtures were developed. From these results, two coatings formulations were in vivo evaluated on mango and papaya. Physicochemical analysis, color change, fruit lesions and C. gloeosporioides growth were determined during storage. In vitro assay indicated that the MIC value of carvacrol and thymol against C. gloeosporioides was 1500 mg/L at pH 5. An additive effect was determined with 750/750 and 1125/375 mg/L mixtures of carvacrol and thymol, respectively. Coated fruits with selected mixtures of carvacrol and thymol presented a delay in firmness, maturity index and color change. Moreover, a fungistatic effect was observed due to a reduction of lesions in coated fruits. These results were corroborated by the increase in the lag phase value and the reduction of the growth rate. Carvacrol and thymol incorporated into edible films and coatings are able to reduce the incidence of anthracnose symptoms on mango and papaya.

Cytotoxic Plant Extracts towards Insect Cells: Bioactivity and Nanoencapsulation Studies for Application as Biopesticides

The potential of plant extracts as bioinsecticides has been described as a promising field of agricultural development. In this work, the extracts of Punica granatum (pomegranate), Phytolacca americana (American pokeweed), Glandora prostrata (shrubby gromwell), Ulex europaeus (gorce), Tagetes patula (French marigold), Camellia japonica red (camellia), Ruta graveolens (rue or herb-of-grace) were obtained, purified, and their activity against Spodoptera frugiperda (Sf9) insect cells was investigated. From the pool of over twenty extracts obtained, comprising different polarities and vegetable materials, less polar samples were shown to be more toxic towards the insect cell line Sf9. Among these, a dichloromethane extract of R. graveolens was capable of causing a loss of viability of over 50%, exceeding the effect of the commercial insecticide chlorpyrifos. This extract elicited chromatin condensation and the fragmentation in treated cells. Nanoencapsulation assays of the cytotoxic plant extracts in soybean liposomes and chitosan nanostructures were carried out. The nanosystems exhibited sizes lower or around 200 nm, low polydispersity, and generally high encapsulation efficiencies. Release assays showed that chitosan nanoemulsions provide a fast and total extract release, while liposome-based systems are suitable for a more delayed release. These results represent a proof-of-concept for the future development of bioinsecticide nanoformulations based on the cytotoxic plant extracts.

Application of essential oils as antimicrobial agents against spoilage and pathogenic microorganisms in meat products

Meat and meat products are perishable products that require the use additives to prevent the spoilage by foodborne microorganisms and pathogenic bacteria. Current trends for products without synthetic preservatives have led to the search for new sources of antimicrobial compounds. Essential oils (EOs), which has been used since ancient times, meet these goals since their effectiveness as antimicrobial agents in meat and meat products have been demonstrated. Cinnamon, clove, coriander, oregano, rosemary, sage, thyme, among others, have shown a greater potential to control and inhibit the growth of microorganisms. Although EOs are natural products, their quality must be evaluated before being used, allowing to grant the Generally Recognized as Safe (GRAS) classification. The bioactive compounds (BAC) present in their composition are linked to their activity, being the concentration and the quality of these compounds very important characteristics. Therefore, a single mechanism of action cannot be attributed to them. Extraction technique plays an important role, which has led to improve conventional techniques in favour of green emerging technologies that allow to preserve better target bioactive components, operating at lower temperatures and avoiding as much as possible the use of solvents, with more sustainable processing and reduced energy use and environmental pollution. Once extracted, these compounds display greater inhibition of gram-positive than gram-negative bacteria. Membrane disruption is the main mechanism of action involved. Their intense characteristics and the possible interaction with meat components make that their application combined with other EOs, encapsulated and being part of active film, increase their bioactivity without modifying the quality of the final product.

Thymol and Thyme Essential Oil-New Insights into Selected Therapeutic Applications

Thymol (2-isopropyl-5-methylphenol) belongs to the phenolic monoterpenes and mostly occurs in thyme species. It is one of the main compounds of thyme essential oil. Both thymol and thyme essential oil have long been used in traditional medicine as expectorant, anti-inflammatory, antiviral, antibacterial, and antiseptic agents, mainly in the treatment of the upper respiratory system. The current search for new directions of biological or therapeutic activities of natural plant substances with known structures includes thyme essential oil and thymol. Novel studies have demonstrated their antibiofilm, antifungal, antileishmanial, antiviral, and anticancer properties. Also, their new therapeutic formulations, such as nanocapsules containing these constituents, can be beneficial in medicinal practice and create opportunities for their extensive use. Extensive application of thymol and thyme essential oil in the healthcare sector is very promising but requires further research and analysis.

Introducing nano/microencapsulated bioactive ingredients for extending the shelf-life of food products

The shelf-life of foods is affected by several aspects, mainly chemical and microbial events, resulting in a considerable decline in consumer's acceptance. There is an increasing interest to substitute synthetic preservatives with the plant-based bioactive ingredients which are safe and natural. However, full implementation of this replacement is postponed by some challenges associated with bioactive ingredients, including their low chemical stability, off-flavor, low solubility, and short-term effectiveness. Encapsulation could overcome these limitations. The present review explains current trends in applying natural encapsulated ingredients for food preservation based on a classified description including essential oils, plant extracts, phenolics, carotenoids, etc. and their application for extending food shelf-life mostly dealing with antimicrobial, ant-browning and antioxidant properties. Encapsulation techniques, especially nanoencapsulation, is a promising strategy to overcome their limitations. Moreover, better results are obtained using a combination of proteins and polysaccharides as wall materials than single polymers. The encapsulation method and type of encapsulants highly influences the releasing mechanism and physicochemical properties of bioactive ingredients. These factors together with optimizing the conditions of encapsulation process leads to a cost-effective and well encapsulated ingredient which is more efficient than its free form in shelf-life improvement. It has been shown that the well-designed encapsulation systems, finally, boost the shelf-life-promoting functions of the bioactive ingredients, mostly due to enhancing their solubility, homogeneity in food matrices and contact surface with deteriorative agents, and providing their prolonged presence over food storage and processing via increasing the thermal and processing stability of bioactive compounds, as well as controlling their release on food surfaces, or/and within food packages. To this end and given the numerous wall and bioactive core substances available, further studies are needed to evaluate the efficiency of many encapsulated forms of both conventional and novel bioactive ingredients in food shelf-life extending since the interactions and anti-spoiling behaviors of the ingredients in various encapsulation systems and foodstuffs are highly variable that should be optimized and characterized before any industrial application.

Zataria multiflora affects clinical symptoms, oxidative stress and cytokines in asthmatic patient: A randomized, double blind, placebo-controlled, phase II clinical trial

BACKGROUND

Z. multiflora effect on clinical symptoms, pulmonary function tests (PFT), oxidative stress and cytokine levels in asthmatic patients were evaluated.

METHODS

36 asthmatic patients were divided to; placebo group (P), two groups treated with Z. multiflora extract (5 and 10 mg/kg/day, as Z5 and Z10, respectively), (n = 12 in each group). Medications were administered three times a day for two months and several parameters were evaluated before treatment (step 0), one (step 1) and two months (step 2) after treatment.

RESULTS

Clinical symptoms and PFTs were significantly improved in Z5 and Z10 groups in steps 1 and 2 compared to step 0 (p < 0.05 to p < 0.001). Improvement of oxidative stress, cytokines levels and their gene expression after treatment with both doses of extract were observed in step 2 compared to step 0 (p < 0.05 to p < 0.001).

CONCLUSION

These results indicated therapeutic value of Z. multiflora for the management of asthma.

Micro/nanoencapsulation strategy to improve the efficiency of natural antimicrobials against Listeria monocytogenes in food products

Listeria monocytogenes (Lm), the etiological agent of listeriosis diseases in humans, is a serious pathogenic microorganism threatening the food safety especially in ready-to-eat food products. Adhesion on both biotic and abiotic surfaces is making it a potential source of contamination by Lm. Also, this bacterium has become more tolerant in food processing conditions, including in the presence of adverse conditions such as cold and dehydration. One of the attractive and effective methods to inhibit the growth of Lm in the food products is using natural antimicrobial agents, which can be a suitable alternative to synthetic preservatives for producing organic food products. The use of pure natural antimicrobials has some limitations including low stability against harsh conditions, low solubility and absorption, and un-controlled release, which can decrease their functions. These limitations have been overcome by using new advanced encapsulation techniques, which have boosted the anti-listerial activity of natural agents. Therefore, the current paper is aiming to review the results of recent studies conducted on using natural antimicrobials added directly or as encapsulated forms into the food formulation to control the growth of Lm. The information of current study can be used by the researchers as well as the food companies for the optimization of food formulations through encapsulation strategies to control Lm and potentially produce safe foods for the consumers.

Viscoelastic behaviour of hyaluronic acid formulations containing carvacrol prodrugs with antibacterial properties

In this paper, we report the development and viscoelastic properties of hyaluronic acid formulations (HA₅, HA₃₀, and HA₆₀, containing 0.5, 3, and 6% HA, respectively) loaded with carvacrol prodrugs (WSCP_S) with antibacterial properties. Notably, antimicrobial studies revealed that WSCP1-2 in both HA₅ and HA₃₀ formulations showed the best minimum inhibitory concentration (MIC) values against Enterococcus faecium (128 mg/L) and Enterococcus faecalis (256 mg/L) compared to those of carvacrol alone or in formulations with HA. Moreover, rheological analyses showed that HA₃₀ composites exhibited a semi-solid consistency, while HA₅ formulations possessed a fluid consistency. Considering these data, HA₃₀ is a useful formulation which guarantees a good percentage of prodrug release (e.g., 30 and 60% for WSCP1 and 2, respectively) as well as a texture suitable for topical administration to treat wounds and/or skin infections.

Comparison of ultrastructural changes and the anticarcinogenic effects of thymol and carvacrol on ovarian cancer cells: which is more effective?

Ovarian cancer is the seventh most common cancer worldwide in women. Many anticancer drugs are currently used clinically have been isolated from plant species or are based on such substances. Thymol (5-methyl-2-isopropylphenol) and carvacrol are oxygenated aromatic compounds from the monoterpene group. They are the main constituents of thyme essential oil and show antiproliferative, antioxidant, and antiseptic properties. The aim of this study is to compare the antiproliferative and apoptotic effects of thymol and carvacrol on SKOV-3 ovarian cancer cell line. The cancer cells were treated with different concentrations of thymol and carvacrol (100, 200, 400, 600 µM) at 24 h and 48 h durations. The cell viability was investigated by MTT assay and analysis of apoptosis with annexin V assay was determined. The study show that thymol and carvacrol significantly induced apoptosis in all groups as dose and time-dependent (p < .05). The data in the present study demonstrated that thymol and carvacrol have apoptotic and antiproliferative properties in a concentration-dependent manner toward ovarian cancer cells. SKOV-3 cancer cell line was much more sensitive to the toxic effect of thymol than carvacrol.

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.

Preparation of Barije (Ferula gummosa) Essential Oil-Loaded Liposomes and Evaluation of Physical and Antibacterial Effect on Escherichia coli O157:H7

ABSTRACT

The aim of this study was to load liposomes with Barije (Ferula gummosa) essential oil (EO) and to evaluate their physical and antibacterial properties. Liposomes were produced with specific ratios of lecithin/cholesterol by thin-film hydration and sonication. The chemical composition of the EO was analyzed by gas chromatography and mass spectroscopy. The physical properties of the liposomes (particle size, polydispersity index, zeta potential, and encapsulation efficiency) were evaluated. The antimicrobial effects of these liposomes against Escherichia coli O157:H7 were determined based on the MIC and disk diffusion results. The effect of subinhibitory concentrations (sub-MICs) of EO against the growth of the bacterium over 24 h was evaluated before and after encapsulation. The major components of EO were β-pinene (60.84%) and α-pinene (9.14%). The mean liposome radius of EO-loaded liposomes was 74.27 to 99.93 nm, which was significantly different from that of the empty liposomes (138.76 nm) (P < 0.05). Addition of cholesterol to the lecithin bilayer increased the particle size and reduced the encapsulation efficiency (P < 0.05). The electrostatic stability of the empty liposomes was improved by adding cholesterol, but when the EO was replaced in the liposomes, there was no significant change in electrostatic stability of liposomes with cholesterol (P < 0.05). MICs were 14.5 μg/mL for the EO-loaded nanoliposomes containing 30 mg of lecithin and 30 mg of cholesterol and 10 μg/mL for nonencapsulated EO. This trend was confirmed by measuring the inhibition zone diameter. Sub-MICs of liposomal EO (containing 60 mg of lecithin) decreased bacterial levels to a greater degree than did free EO, especially at 50 and 75% of the MIC.

HIGHLIGHTS

Nanostructured Systems Improve the Antimicrobial Potential of the Essential Oil from Cymbopogon densiflorus Leaves

The physicochemical characteristics of nanostructured suspensions are important prerequisites for the success of new drug development. This work aimed to develop nanometric systems containing Cymbopogon densiflorus leaf essential oil and to evaluate their antimicrobial activity. The essential oil was isolated by hydrodistillation from leaves and analyzed by GC-MS. The main constituents were found to be trans-p-mentha-2,8-dien-1-ol, cis-p-mentha-2,8-dien-1-ol, trans-p-mentha-1(7),8-dien-2-ol, cis-piperitol, and cis-p-mentha-1(7),8-dien-2-ol. In silico prediction analysis suggested that this oil possesses antimicrobial potential and the main mechanism of action might be the peptidoglycan glycosyltransferase inhibition. Nanoemulsions were prepared by the phase inversion method, and liposomes were made by the film hydration method. Qualitative evaluation of the antimicrobial activity was performed by the diffusion disk assay with 24 microorganisms; all of them were found to be sensitive to the essential oil. Subsequently, this property was quantified by the serial microdilution technique, where the nanoformulations demonstrated improved activity in comparison with the free oil. Bactericidal action was tested by the propidium iodide method, which revealed that free essential oil and nanoemulsion increased cytoplasmic membrane permeability, while no difference was observed between negative control and liposome. These results were confirmed by images obtained using transmission electron microscopy. This study has shown an optimization in the antimicrobial activity of C. densiflorus essential oil by a nanoemulsion and a liposomal formulation of the active substances.

The alarming antimicrobial resistance in ESKAPEE pathogens: Can essential oils come to the rescue?

Antibiotics, considered as a backbone of modern clinical-medicines, are facing serious threats from emerging antimicrobial-resistance (AMR) in several bacteria from nosocomial and community origins and is posing a serious human-health concern. Recent commitment by the Heads of States at the United Nations General Assembly (UNGA, 2016) for coordinated efforts to curb such infections illustrates the scale of this problem. Amongst the drug-resistant microbes, major threat is posed by the group named as ESKAPEE, an acronym for Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., and Escherichia coli, comprising high to critical drug-resistant, World Health Organization Critical Priority I and II pathogens. The drying pipeline of effective and new antibiotics has worsened the situation with looming threat of heading to a 'post-antibiotic era'. This necessitates novel and effective approaches to combat this life-threatening issue. Medicinal and aromatic plants are hailed as the reservoir of bioactive compounds and can serve as a source of antimicrobial compounds, and some recent leads show that essential oils (EOs) may provide an effective solution for tackling AMR. EOs have shown wide-spectrum antimicrobial potentials via targeting the major determinants of pathogenicity, drug-resistance and its spread including cell membrane, drug efflux pumps, quorum sensing, biofilms and R-plasmids. Latest reports confirm the EOs having strong direct-killing or re-sensitizing potentials to replace or rejuvenate otherwise fading antibiotics arsenal. We discuss herein possibilities of using EOs directly for antimicrobial potentials or in combination with antibiotics to potentiate the later for combating AMR in ESKAPEE pathogens. The current understandings, success stories and challenges for translational success have also been discussed.

Influence of modified starches as wall materials on the properties of spray-dried lemongrass oil

The use of lemongrass oil as food preservative present great potential, however it has high volatility and intense aroma, making them limited to be used as food additives. Microencapsulation processes become interesting alternatives to overcome these issues. This work investigated the influence of the partial replacement of gum arabic by modified starches on the microencapsulation of lemongrass oil as core material. Gum arabic and its combinations with modified starches: cassava and corn maltodextrins with different dextrose equivalent (DE) and octenyl succinic anhydride modified starch (OSA-starch) were studied. The emulsions were spray dried at controlled temperature of 170 °C. The evaluated parameters particles solubility, moisture content, and oil composition did not showed significant differences among the treatments. Replacement of gum arabic by maltodextrin DE20 and OSA-starch resulted in higher wetting times. Oil retention was increased (81.2%) when gum arabic was replaced by OSA-starch; the treatment without substitution, with only gum arabic had 67.5% of oil retention. Application of OSA-starch in association with gum arabic in microencapsulation by spray drying of lemongrass oil presented greater potential to be used due to its higher oil retention. Polymer blends should be assessed since they present advantages over individually applied polymers. Although maltodextrins show some differences compared to the treatment with only gum arabic, it may also be a viable alternative because of its lower cost.

Chemical diversity in leaf and stem essential oils of Origanum vulgare L. and their effects on microbicidal activities

Essential oils (EOs) from the stems and leaves of Origanum vulgare L. grown in Saudi Arabia and Jordan were analyzed by gas chromatography-mass spectrometry (GC-MS) and GC-flame ionization detector (FID) techniques on two different columns (polar and nonpolar). A detailed phytochemical analysis led to the identification of 153 constituents of these essential oils. Both Saudi and Jordanian plants are classified by chemotypes rich in cymyl-compounds. However, the Saudi Origanum contains carvacrol as the major component and is, thus, characterized as a carvacrol chemotype, while the Jordanian Origanum contains thymol as the major component, and, thus, it is classified as a thymol chemotype. In addition, the antimicrobial activities of the studied EOs and their major components, including carvacrol and thymol, were evaluated against various Gram-positive and Gram-negative microorganisms. All the tested compounds exhibited significant antimicrobial activity against all the tested bacteria. Among them, thymol demonstrated superior activity against all the tested organisms, followed by carvacrol. Moreover, results on oil composition and oil yield of O. vulgare L. from different parts of the world is compared in detail with the present outcomes.

Carvacrol Loaded Solid Lipid Nanoparticles of Propylene Glycol Monopalmitate and Glyceryl Monostearate: Preparation, Characterization, and Synergistic Antimicrobial Activity

To develop solid lipid nanoparticles (SLNs) with stable lipid matrix structures for the delivery of bioactive compounds, a new class of SLNs was studied using propylene glycol monopalmitate (PGMP) and glyceryl monostearate (GMS) mixtures and carvacrol as a model lipophilic antimicrobial. Stable SLNs were fabricated at PGMP:GMS mass ratios of 2:1 and 1:1, and the carvacrol loading was up to 30% of lipids with >98% encapsulation efficiency and absence of visual instability. Fluorescence spectra and release profiles indicated the carvacrol was successfully encapsulated and homogeneously distributed within the SLNs. SLNs fabricated with equal masses of PGMP and GMS had better stability of carvacrol during storage and higher sphericity than those with a ratio of 2:1 and were much more effective than free carvacrol against Escherichia coli O157:H7 and Staphylococcus aureus. These findings demonstrated the potential applications of the studied SLNs in delivering lipophilic bioactive compounds in food and other products.

Encapsulation of Essential Oils for the Development of Biosourced Pesticides with Controlled Release: A Review

Essential oil (EO) encapsulation can be carried out via a multitude of techniques, depending on applications. Because of EOs’ biological activities, the development of biosourced pesticides with EO encapsulation is of great interest. A lot of methods have been developed; they are presented in this review, together with the properties of the final products. Encapsulation conserves and protects EOs from outside aggression, but also allows for controlled release, which is useful for applications in agronomy. The focus is on the matrices that are of interest for the controlled release of their content, namely: alginate, chitosan, and cyclodextrin. Those three matrices are used with several methods in order to create EO encapsulation with different structures, capacities, and release profiles.

Novel cuminaldehyde self-emulsified nanoemulsion for enhanced antihepatotoxicity in carbon tetrachloride-treated mice

Objectives

Cuminaldehyde self-emulsified nanoemulsion (CuA-SEN) was prepared and optimised to improve its oral bioavailability and antihepatotoxicity.

Methods

Cuminaldehyde self-emulsified nanoemulsion was developed through the self-nanoemulsification method using Box–Behnken Design (BBD) tool while appropriate physicochemical indices were evaluated. The optimised CuA-SEN was characterised via droplet size (DS), morphology, polydispersity index (PDI), zeta potential (ZP), entrapment efficiency, in-vitro release, and pharmacokinetic studies while its antihepatotoxicity was evaluated.

Key findings

Cuminaldehyde self-emulsified nanoemulsion with acceptable characteristics (mean DS-48.83 ± 1.06 nm; PDI-0.232 ± 0.140; ZP-29.92 ± 1.66 mV; EE-91.51 ± 0.44%; and drug-loading capacity (DL)-9.77 ± 0.75%) was formulated. In-vitro drug release of CuA-SEN significantly increased with an oral relative bioavailability of 171.02%. Oral administration of CuA-SEN to CCl4-induced hepatotoxicity mice markedly increased the levels of superoxide dismutase, glutathione and catalase in serum. Also, CuA-SEN reduced the levels of tumour necrosis factor-alpha and interleukin-6 in both serum and liver tissues while aspartate aminotransferase, alanine aminotransferase and malonaldehyde levels were significantly decreased.

Conclusions

These findings showed that the improved bioavailability of cuminaldehyde via SEN provided an effective approach for enhancing antioxidation, anti-inflammation and antihepatotoxicity of the drug.

Application of the combinatorial approaches of medicinal and aromatic plants with nanotechnology and its impacts on healthcare

BACKGROUND

Medicinal and aromatic plants are natural raw materials. Since ancient times these herbal materials are being commonly used as herbal drugs, food products, and cosmetics. The phytomolecules isolated from the medicinal and aromatic plants (MAPs) are in high demand specifically in drug industries. However, these phytomolecules have certain limitations of low absorption, high toxicity, and other side effects, bioavailability and efficacy. These limitations may be overcome by using nanotechnological tools. The plant extract or essential oil of MAPs are also useful in the synthesis of nanoparticles. In future this combinatorial application of MAPs and nanotechnology would be advantageous in the healthcare area.

METHODS

Literature search was performed using databases like Pubmed, Scopus and Google Scholar with the keywords "nanoparticles," "phytomolecules," "medicinal and aromatic plants" and "green synthesis of nanoparticles" in the text.

RESULT

Phytomolecules of medicinal and aromatic plants like curcumin, camptothecin, thymol, and eugenol have certain limitations of bioavailability, efficacy, and solubility. It limits its biological activity and therefore application in the biomedical area. The increment in the biological activity and sustained delivery was observed after the encapsulation of these potent phytomolecules encapsulated in the nanocarriers. Besides, MAPs and/or their molecules/oils mediate the synthesis of metal nanocarriers with less toxicity.

CONCLUSION

This review highlights the impact of the combination of the MAPs with the nanotechnology along with the challenges. It would be an effective technique for the efficient delivery of different phytomolecules and also in the synthesis of novel nano-materials, which escalates the opportunity of exploration of potential molecules of MAPs. Graphical abstract Graphical representation of the combinatorial approach of MAPs and nanotechnology.

Controlled Release Mechanism and Antibacterial Effect of Layer-By-Layer Self-Assembly Thyme Oil Microcapsule

Thyme essential oil-loaded microcapsules (TMS) were fabricated using natural polysaccharide chitosan (CS) and sodium alginate (SA) as the shell material via the method of layer-by-layer (LBL) assembly. The accumulated release rates of thyme oil and microcapsules at 4 °C were 42.50% and 10.16%, respectively. After heating at 100 °C for 5 hr, the release rate of the 0, 2, 4, 6 layers assembled microcapsules were 100%, 48.84%, 28.38%, 19.3%, severally. Microcapsules also had good pH sensitivity in the range of 4 to 10. Antimicrobial function studies showed that the microcapsules are more effective than thyme oil for three tested microorganisms. When the temperature rose from 37 °C to 121 °C, the antibacterial zone of thyme oil gradually decreased from 18.5 ± 0.6 mm to 12.3 ± 0.6 mm, although inhibition rate of microcapsules increased from 87.97% to 99.75%. The antibacterial effect of thyme oil declined with the increase of pH, in terms of microcapsules, the efficiency was better under acidic or alkaline conditions. The thyme oil microcapsules can suppress the growth of Staphylococcus aureus in milk and prolong its shelf life. It was determined that this microcapsule could be a potential alternative as a natural antimicrobial agent in food and pharmaceutical industries. PRACTICAL APPLICATION: This work provided release performance and mechanism of layer-by-layer (LBL) thyme oil microcapsule under different conditions, and further studies showed its antibacterial ability to explore how herb essential oils can be potentially applied in food packaging and antibacterial areas.

Improving the Efficacy of Essential Oils as Antimicrobials in Foods: Mechanisms of Action

The consumer preference for clean-label products is requiring the food industry to reformulate their products by replacing artificial additives with natural alternatives. Essential oils are natural antimicrobials isolated from plant sources that have the potential to combat many foodborne pathogens and spoilage organisms. This review begins by discussing the antimicrobial properties of essential oils, the relationships between their chemical structure and antimicrobial efficacy, and their potential limitations for commercial applications (such as strong flavor, volatility, and chemical instability). We then review the commonly used methods for screening the antimicrobial efficacy of essential oils and elucidating their mechanisms of action. Finally, potential applications of essential oils as antimicrobials in foods are reviewed and the major types of food-grade delivery systems available for improving their efficacy are discussed.

Summer Savory (Satureja hortensis L.) Extract as Natural Feed Additive in Broilers: Effects on Growth, Plasma Constituents, Immune Response, and Ileal Microflora

Simple Summary

The growth-promoting effect of many herbs and their extracts in poultry has been reported in literature. Therefore, the objective of this feeding trial was to determine the effect of different levels of summer savory (Satureja hortensis L.) extract in diet on broilers performance, immune response, hematology, and microbiota. Based on findings, dietary supplementation with summer savory extract, as natural feed additive, sustained growth traits and improved the feed efficiency and health status of broilers.

Abstract

This study investigated the effects of summer savory (Satureja hortensis L.) extract (SSE) on growth, plasma constituents, immune response, and gut microbiota of broiler chickens. A total of 300 day-old broiler chicks were randomly assigned to five dietary treatments containing five replicates of 12 birds each. The treatments consisted of a controldiet without feed additive and experimental diets supplemented with four levels of SSE (100, 200, 300, and 400 mg/kg, respectively). Results showed no significant effect of SSE supplementation on broiler body weight gain (p > 0.05), but feed conversion ratio was significantly (p < 0.05) improved when fed 400 mg/kg SSE compared to control. Most of the blood parameters and immune response criteria studied were improved (p < 0.05) by SSE supplementation. There was no dietary effect on Lactobacilli count (p > 0.05); conversely, Escherichia coli count was reduced and the Lactobacilli/E. coli ratio improved with SSE (p < 0.05). Based on our findings, it was concluded that supplementation of the diet with SSE up to 400 mg/kg sustained growth traits and improved the feed efficiency and health status of broilers. However, more research is needed on this subject in order to better understand the mode of action of the extract used.

New findings on the incorporation of essential oil components into liposomes composed of lipoid S100 and cholesterol

The encapsulation of essential oil components into liposomes was demonstrated to improve their solubility and chemical stability. In this study, we investigated the effect of chemical structure, Henry's law constant (H_c), and aqueous solubility of essential oil components on their liposomal encapsulation. Estragole, eucalyptol, isoeugenol, pulegone, terpineol, and thymol were encapsulated in lipoid S100-liposomes using the ethanol injection method. The H_c values were determined. The incorporation in liposomes was more efficient (encapsulation efficiency > 90%) for the essential oil components exhibiting low aqueous solubility (estragole, isoeugenol, and pulegone). Moreover, efficient entrapment into vesicles (loading rate > 18%) was obtained for isoeugenol, terpineol, and thymol. This result suggests that the presence of a hydroxyl group in the structure and a low Hc value enhance the entrapment of essential oil components into liposomes. Furthermore, drug release rate from liposomes was controlled by the loading rate of essential oil components into liposomes, the size of particles, the location of essential oil components within the lipid bilayer, and the cholesterol incorporation rate of liposomes. Finally, considerable concentrations of isoeugenol, pulegone, terpineol, and thymol were retained in liposomes after 10 months with respect to the initial concentration.