Formulation and Evaluation of a Clove Oil-Encapsulated Nanofiber Formulation for Effective Wound-Healing

Clove Essential Oil: Chemical Profile, Biological Activities, Encapsulation Strategies, and Food Applications

Plants have proven to be important sources for discovering new compounds that are useful in the treatment of various diseases due to their phytoconstituents. Clove (Syzygium aromaticum L.), an aromatic plant widely cultivated around the world, has been traditionally used for food preservation and medicinal purposes. In particular, clove essential oil (CEO) has attracted attention for containing various bioactive compounds, such as phenolics (eugenol and eugenol acetate), terpenes (β-caryophyllene and α-humulene), and hydrocarbons. These constituents have found applications in cosmetics, food, and medicine industries due to their bioactivity. Pharmacologically, CEO has been tested against a variety of parasites and pathogenic microorganisms, demonstrating antibacterial and antifungal properties. Additionally, many studies have also demonstrated the analgesic, antioxidant, anticancer, antiseptic, and anti-inflammatory effects of this essential oil. However, CEO could degrade for different reasons, impacting its quality and bioactivity. To address this challenge, encapsulation is viewed as a promising strategy that could prolong the shelf life of CEO, improving its physicochemical stability and application in various areas. This review examines the phytochemical composition and biological activities of CEO and its constituents, as well as extraction methods to obtain it. Moreover, encapsulation strategies for CEO and numerous applications in different food fields are also highlighted.

Chitosan-Oxidized Pullulan Hydrogels Loaded with Essential Clove Oil: Synthesis, Characterization, Antioxidant and Antimicrobial Properties

Emulsion hydrogels are promising materials for encapsulating and stabilizing high amounts of hydrophobic essential oils in hydrophilic matrices. In this work, clove oil-loaded hydrogels (CS/OP-C) are synthesized by combining covalent and physical cross-linking approaches. First, clove oil (CO) was emulsified and stabilized in a chitosan (CS) solution, which was further hardened by Schiff base covalent cross-linking with oxidized pullulan (OP). Second, the hydrogels were subjected to freeze-thaw cycles and, as a result, the clove oil was stabilized in physically cross-linked polymeric walls. Moreover, due to cryogelation, the obtained hydrogels exhibited sponge-like porous interconnected morphology (160-250 µm). By varying the clove oil content in the starting emulsion and the degree of cross-linking, the hydrogels displayed a high water retention capacity (swelling ratios between 1300 and 2000%), excellent elastic properties with fast shape recovery (20 s) after 70% compression, and controlled in vitro clove oil release in simulated skin conditions for 360 h. Furthermore, the prepared clove oil-loaded hydrogels had a strong scavenging activity of 83% and antibacterial and antifungal properties, showing a bacteriostatic effect after 48 and 72 h against S. aureus and E. coli. Our results recommend the new clove oil-embedded emulsion hydrogels as promising future materials for application as wound dressings.

Antimicrobial Activity of Syzygium aromaticum Essential Oil in Human Health Treatment

The use of natural compounds to prevent and treat infective diseases is increasing its importance, especially in the case of multidrug-resistant (MDR) microorganisms-mediated infections. The drug resistance phenomenon is today a global problem, so it is important to have available substances able to counteract MDR infections. Syzygium aromaticum (L.) Merr. & L.M. Perry (commonly called clove) is a spice characterized by several biological properties. Clove essential oil (EO) consists of numerous active molecules, being eugenol as the principal component; however, other compounds that synergize with each other are responsible for the biological properties of the EO. S. aromaticum is traditionally used for bowel and stomach disorders, cold and flu, oral hygiene, tooth decay, and for its analgesic action. Its EO has shown antioxidant, antimicrobial, anti-inflammatory, neuro-protective, anti-stress, anticancer, and anti-nociceptive activities. This review aims to investigate the role of E. S. aromaticum EO in the counteraction of MDR microorganisms responsible for human disorders, diseases, or infections, such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi, Candida albicans, Giardia lamblia, Streptococcus mutans, Porphyromonas gingivalis, and Klebsiella pneumoniae. This study might orient clinical researchers on future therapeutic uses of S. aromaticum EO in the prevention and treatment of infectious diseases.

Chitosan coated clove oil-based nanoemulsion: An attractive option for oral delivery of leflunomide in rheumatoid arthritis

Rheumatoid arthritis (RA), a distressing inflammatory autoimmune disease, is managed mainly by Disease-modifying antirheumatic drugs (DMARDs), e.g. leflunomide (LEF). LEF (BCS class II) has limited solubility and adverse effects following its systemic exposure. The appealing antirheumatic properties of both clove oil and chitosan (CS) were exploited to design oral leflunomide (LEF)-loaded nanoemulsion (NE) system to augment the therapeutic action of LEF and decrease its systemic side effects as well. Different LEF-NEs were prepared using clove oil, Tween® 20 (surfactant), and PEG 400(co-surfactant) and characterized by thermodynamic stability, percentage transmittance, cloud point, size analysis, and drug content. Optimized LEF-NE was subjected to CS coating forming LEF-CS-NE that exhibited nanometric size range, prolonged drug release, and good physical stability. In vivo anti-rheumatic activity of pure LEF, market LEF, and LEF-CS-NE was assessed utilizing a complete Freund's adjuvant (CFA) rat model. Treatment with LEF-CS-NE reduced edema rate (48.68% inhibition) and caused a marked reduction in interleukin-6 (IL-6) (510.9 ± 2.48 pg/ml), tumor necrosis factor- α (TNF-α) (397.3 ± 2.53 pg/ml), and rheumatoid factor (RF) (42.58 ± 0.49 U/ml). Furthermore, LEF-CS-NE reduced serum levels of glutamic pyruvic transaminase (GPT) to (83.19%) and glutamic oxaloacetic transaminase (GOT) to (40.68%) compared to the control + ve group. The effects of LEF-CS-NE were also superior to both pure and market LEF and showed better results in histopathological studies of paws, liver, kidney, lung, and heart. The remarkable therapeutic and safety profile of LEF-CS-NE makes it a potential oral system for the management of RA.

Development of poly(hydroxybutyrate) film incorporated with nano silica and clove essential oil intended for active packaging of brown bread

The objective of current study was to develop Poly(hydroxybutyrate) (PHB) based active packaging film with long lasting antimicrobial potential in food-packaging applications. For developing such films, PHB was incorporated with poly(ethylene glycol) (PEG) as a plasticizer, nano-silica (n-Si) as strengthening material and clove essential oil (CEO) as an antimicrobial agent. These solvent-casted films with varying concentration of n-Si (0.5, 1, 1.5, 2 %) and 30 % CEO of total polymer matrix weight i.e., PHB/PEG (90/10) were prepared and studied on the basis of morphological, mechanical, thermal, degradation and antimicrobial behaviours. The presence of CEO and n-Si was confirmed by Fourier transform infrared spectroscopy (FTIR). Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) were used to investigate homogeneous dispersal of n-Si in polymer matrix. PHB/PEG/CEO/Si 1.0 film was selected as optimized one after mechanical testing and therefore further carried for antimicrobial testing. This selected film extended the shelf-life of brown bread up to 10 days comparable to bread wrapped in polyethylene. This revealed that PHB/PEG/CEO/Si 1.0 exhibited superior antibacterial activity against the food borne microbes i.e., Escherichia coli, Staphylococcus aureus and Aspergillus niger. Our findings indicate that this film improved the shelf-life of packaged bread and has promising features for active food packaging.

Levofloxacin loaded clove oil nanoscale emulgel promotes wound healing in Pseudomonas aeruginosa biofilm infected burn wound in mice

Owing to their tolerance to antibiotics, bacterial biofilms continue to pose a threat to mankind and are leading cause for non-healing of burn wounds. Within the biofilm matrix, antibiotics become functionally inactive due to restricted penetration and enzymatic degradation leading to rise of antimicrobial resistance. The objective of present investigation was to develop and characterize levofloxacin (LFX) loaded clove oil nanoscale emulgel (LFX-NE gel) and evaluate its in vivo therapeutic efficacy in Pseudomonas aeruginosa biofilm infected burn wound in mice. The optimized emulgel was found to possess good texture profile and showed shear thinning behavior. In vitro release study demonstrated complete drug release in 8 h and emulgel was found to be stable for 3 months at 25 °C and 40 °C. In vivo study revealed biofilm dispersal, complete wound closure, re-epithelialization and collagen deposition by LFX-NE gel in comparison to various control groups. LFX-NE gel was able to clear the infection within 7 days of treatment and promote wound healing as well. Therefore, administration of LFX-incorporated NE gel could be a beneficial treatment strategy for P. aeruginosa biofilm-infected burn wounds.

Nanoemulsions of Clove Oil Stabilized with Chitosan Oleate-Antioxidant and Wound-Healing Activity

Clove oil (CO) is a powerful antioxidant essential oil (EO) with anti-inflammatory, anesthetic, and anti-infective properties. It can be therefore considered a good candidate for wound-healing applications, especially for chronic or diabetic wounds or burns, where the balance of reactive oxygen species (ROS) production and detoxification is altered. However, EOs require suitable formulations to be efficiently administered in moist wound environments. Chitosan hydrophobically modified by an ionic interaction with oleic acid (chitosan oleate, CSO) was used in the present work to stabilize CO nanoemulsions (NEs). The dimensions of the NE were maintained at around 300 nm as the volume distribution for up to six months, and the CO content did not decrease to under 80% over 4 months, confirming the good stabilizing properties of CSO. The antioxidant properties of the CO NE were evaluated in vitro by a 2,2-diphenil-2-picrylhydrazyl hydrate (DPPH) assay, and in fibroblast cell lines by electron paramagnetic resonance (EPR) using α-phenyl-N-tert-butyl nitrone (PBN) as a spin trap; a protective effect was obtained comparable to that obtained with α-tocopherol treatment. In a murine burn model, the ability of CO formulations to favor macroscopic wound closure was evidenced, and a histological analysis revealed a positive effect of the CO NE on the reparation of the lesion after 18 days. Samples of wounds at 7 days were subjected to a histological analysis and parallel dosage of lipid peroxidation by means of a thiobarbituric acid-reactive substances (TBARS) assay, confirming the antioxidant and anti-inflammatory activity of the CO NE.

Hydrolytic Degradation and Bioactivity of Electrospun PCL-Mg-NPs Fibrous Mats

In this work, the in vitro degradation behavior of nanofibers was investigated in phosphate buffer solution (PBS) and simulated body fluid (SBF) to study their degradation behavior, as well as their bioactivity. The degradation was studied at different immersion times in order to evaluate how the presence of Mg-based nanoparticles can affect the degradation in terms of morphology, crystallinity, degradation rate and pH changes, and finally to evaluate the bioactivity of PCL-based electrospun nanofibers. We found that the degradation of the materials takes more than 3 months; however, the presence of nanoparticles seems to have an accelerating effect on the degradation of the electrospun nanofibers based on PCL. In fact, a reduction in diameter of almost 50% was observed with the highest content of both types of nanoparticles and an increase in crystallinity after 296 days of immersion in PBS. Moreover, the carbonyl index was calculated from an FTIR analysis, and a reduction of 20-30% was observed due to the degradation effect. Additionally, the bioactivity of PCL-based electrospun nanofibers was studied and the formation of crystals on the nanofibers surface was detected, except for neat electrospun PCL related to the formation of NaCl and apatites, depending on the amount and type of nanoparticles. The presence of apatites was confirmed by an XRD analysis and FT-IR analysis observing the characteristic peaks; furthermore, the EDX analysis demonstrated the formation of apatites than can be reconducted to the presence of HA when 20 wt% of nanoparticles is added to the PCL electrospun fibers.

Recent Progress of Electrospun Herbal Medicine Nanofibers

Herbal medicine has a long history of medical efficacy with low toxicity, side effects and good biocompatibility. However, the bioavailability of the extract of raw herbs and bioactive compounds is poor because of their low water solubility. In order to overcome the solubility issues, electrospinning technology can offer a delivery alternative to resolve them. The electrospun fibers have the advantages of high specific surface area, high porosity, excellent mechanical strength and flexible structures. At the same time, various natural and synthetic polymer-bound fibers can mimic extracellular matrix applications in different medical fields. In this paper, the development of electrospinning technology and polymers used for incorporating herbal medicine into electrospun nanofibers are reviewed. Finally, the recent progress of the applications of these herbal medicine nanofibers in biomedical (drug delivery, wound dressing, tissue engineering) and food fields along with their future prospects is discussed.

Recent advances in nutritional composition, phytochemistry, bioactive, and potential applications of Syzygium aromaticum L. (Myrtaceae)

Syzygium aromaticum is an aromatic plant native to Indonesia, and introduced to tropical regions worldwide. As an ingredient in perfumes, lotions, and food preservation, it is widely used in the food and cosmetic industries. Also, it is used to treat toothache, ulcers, type 2 diabetes, etc. A variety of nutrients such as amino acids, proteins, fatty acids, and vitamins are found in S. aromaticum. In addition to eugenol, isoeugenol, eugenol acetate, β-caryophyllene and α-humulene are the main chemical constituents. The chemical constituents of S. aromaticum exhibit a wide range of bioactivities, such as antioxidant, antitumor, hypoglycemic, immunomodulatory, analgesic, neuroprotective, anti-obesity, antiulcer, etc. This review aims to comprehend the information on its taxonomy and botany, nutritional composition, chemical composition, bioactivities and their mechanisms, toxicity, and potential applications. This review will be a comprehensive scientific resource for those interested in pursuing further research to explore its value in food.

Essential Oil—Loaded Nanofibers for Pharmaceutical and Biomedical Applications: A Systematic Mini-Review

Essential oils (EOs) have been widely exploited for their biological properties (mainly as antimicrobials) in the food industry. Encapsulation of EOs has opened the way to the utilization of EOs in the pharmaceutical and biomedical fields. Electrospinning (ES) has proved a convenient and versatile method for the encapsulation of EOs into multifunctional nanofibers. Within the last five years (2017–2022), many research articles have been published reporting the use of ES for the fabrication of essential oil—loaded nanofibers (EONFs). The objective of the present mini-review article is to elucidate the potential of EONFs in the pharmaceutical and biomedical fields and to highlight their advantages over traditional polymeric films. An overview of the conventional ES and coaxial ES technologies for the preparation of EONFs is also included. Even though EONFs are promising systems for the delivery of EOs, gaps in the literature can be recognized (e.g., stability studies) emphasizing that more research work is needed in this field to fully unravel the potential of EONFs.

Fabrication and Optimization of Essential-Oil-Loaded Nanoemulsion Using Box-Behnken Design against Staphylococos aureus and Staphylococos epidermidis Isolated from Oral Cavity

Oral bacterial infections are fairly common in patients with diabetes mellitus; however, due to limited treatment options, herbal medicines are considered an alternate solution. This study aimed to formulate a stable essential-oil-loaded nanoemulsion for the treatment of oral bacterial infections. Essential oils from edible sources including coriander, clove, cinnamon and cardamom were extracted by hydrodistillation. The response surface methodology was used to optimize the nanoemulsion formulation by applying the Box–Behnken design. The oil concentration, surfactant concentration and stirring speed were three independent factors, and particle size and polydispersity index were two responses. The particle size, polydispersity index and zeta potential of the optimized formulation were 130 mm, 0.222 and −22.9, respectively. The ATR-FTIR analysis revealed that there was no incompatibility between the active ingredients and the excipients. A significant release profile in active ingredients of nanoemulsion, i.e., 88.75% of the cinnamaldehyde and 89.33% of eugenol, was recorded after 24 h. In the ex vivo goat mucosal permeation study, 71.67% of the cinnamaldehyde permeated and that of the eugenol 70.75% from the nanoemulsion. The optimized formulation of the essential-oil-loaded nanoemulsion showed a 9 mm zone of inhibition against Staphylococcus aureus and Staphylococcus epidermidis, whereas in anti-quorum sensing analysis, the optimized nanoemulsion formulation showed an 18 mm zone of inhibition. It was concluded that formulated essential-oil-loaded nanoemulsion can be used against S. epidermidis and S. aureus infections in oral cavity.

Phosphorylated Curdlan Gel/Polyvinyl Alcohol Electrospun Nanofibres Loaded with Clove Oil with Antibacterial Activity

Fibrous membranes based on natural polymers obtained by the electrospinning technique are a great choice for wound dressings. In order to promote an efficient wound repair, and to avoid antibiotics, antibacterial plant extracts can be incorporated. In the present work, the new electrospun nanofibre membranes based on monobasic phosphate curdlan (PCurd) and polyvinyl alcohol (PVA) were obtained for the first time. To establish the adequate mixing ratio for electrospinning, the behaviour of the PCurd and PVA mixture was studied by viscometry and rheology. In order to confer antimicrobial activity with the nanofibre membrane, clove essential oil (CEO) was incorporated into the electrospun solution. Well-defined and drop-free nanofibres with a diameter between 157 nm and 110 nm were obtained. The presence of CEO in the obtained nanofibres was confirmed by ATR–FTIR spectroscopy, by the phenolic and flavonoid contents, and by the antioxidant activity of the membranes. In physiological conditions, CEO was released from the membrane after 24 h. The in vivo antimicrobial tests showed a good inhibitory activity against E. coli and higher activity against S. aureus. Furthermore, the viability cell test showed the lack of cytotoxicity of the nanofibre membrane with and without CEO, confirming its potential use in wound treatment.

Clove Oil-Incorporated Antibacterial Gelatin-Chitosan Cryogels for Tissue Engineering: An In Vitro Study

Infections are a leading cause of mortality and amputations among patients with burns and chronic wounds, respectively. Moreover, the extensive use of antibiotics has led to the rapid spreading of drug resistance among microorganisms. Alternatively, plant-derived natural products, which have been used as traditional therapies for several centuries, are recently gaining popularity as they are relatively affordable and easily available in many developing countries where modern medications are expensive or unavailable. In this study, clove essential oil is used for its antimicrobial property and is further incorporated into cryogels to increase its bioavailability and prolong its bioactivity. The oil-incorporated cryogels are macroporous, biodegradable, possess mechanical properties similar to commercial skin substitutes, are cytocompatible, antibacterial, and allow long-term sustained release of oil for up to at least 14 days. Additionally, clove oil aids the faster closure of in vitro scratch wounds by improving the migration of fibroblasts. This work presents a novel, bioactive scaffold that has the potential to be used as a dermal substitute and serves as an alternative to commercial skin substitutes.

Functional Coatings by Natural and Synthetic Agents for Insect Control and Their Applications

Insect repellent textiles offer protection against disease-causing vectors such as mosquitoes, flies, and ticks. Protection is based on the incorporation of insect repellent compounds present in plant oil derivatives or synthetic oils. The effectiveness and application of natural insect repellents such as citronella grass, lemongrass, rosemary, peppermint, holy basil, tea tree, neem, lavender, thyme, lemon eucalyptus, clove, and cinnamon oils, as well as synthetic compounds permethrin, allethrin, malathion, DEET, DETA, IR3535, and picaridin, are compared here. The insect repellent and insecticidal effectiveness of natural compounds in their pure form are very low due to their high volatility. The effectiveness has been greatly improved through slow-release systems such as encapsulation of the essential oils and is comparable to synthetic compounds used for insect control purposes. Due to the lasting toxicity of synthetic compounds to humans and the environment, the use of natural compounds should become a more preferred method of insect control.

Gellan Gum-Based Bilayer Mucoadhesive Films Loaded with Moxifloxacin Hydrochloride and Clove Oil for Possible Treatment of Periodontitis

Background/Objective

Periodontitis is a widely spread oral infection and various antibiotics are utilized for its treatment, but high oral doses and development of antibiotic resistance limit their use. This study was aimed at development of natural polymer-based mucoadhesive bilayer films loaded with moxifloxacin hydrochloride (Mox) and clove essential oil (CEO) to potentially combat bacterial infection associated with periodontitis.

Methods

Films were synthesized by double solvent casting technique having an antibiotic in the gellan gum-based primary layer with clove oil in a hydroxyethyl cellulose-based secondary layer.

Results

Prepared films were transparent, flexible, and showed high antibacterial response against both gram-positive and gram-negative bacteria. The films showed excellent pharmaceutical attributes in terms of drug content, folding endurance, swelling index, and mucoadhesive strength. Solid state characterization of formulation showed successful incorporation of drug and oil in separate layers of hydrogel structure. An in-vitro release study showed an initial burst release of drug followed by sustained release for up to 48 hours.

Conclusion

The prepared mucoadhesive bilayer buccal films could be used as a potential therapeutic option for the management of periodontitis.

ATR-FTIR-MIR Spectrometry and Pattern Recognition of Bioactive Volatiles in Oily versus Microencapsulated Food Supplements: Authenticity, Quality, and Stability

Fourier transform infrared spectroscopy on the middle infrared region (ATR-FTIR-MIR) proved to be a convenient and reliable technique to evaluate foods' quality and authenticity. Plants' essential oils are bioactive mixtures used as such or in different oily or microencapsulated formulations, beneficial to human health. Six essential oils (thyme, oregano, juniperus, tea tree, clove, and cinnamon) were introduced in three oily formulations (Biomicin, Biomicin Forte, and Biomicin urinary) and these formulations were microencapsulated on fructose and maltodextrin matrices. To study their stability, the microencapsulated powders were kept under light irradiation for 14 days at 25 °C or introduced in biopolymer capsules. All variants were analysed by ATR-FTIR-MIR, recording wavenumbers and peak intensities (3600-650 cm^-1). The data were processed by Unscrambler and Metaboanalyst software, with specific algorithms (PCA, PLSDA, heatmaps, and random forest analysis). The results demonstrated that ATR-FTIR-MIR can be successfully applied for fingerprinting and finding essential oil biomarkers as well as to recognize this pattern in final microencapsulated food supplements. This study offers an improved ATR-FTIR-MIR procedure coupled with an adequate chemometric analysis and accurate data interpretation, to be applied for the evaluation of authenticity, quality, traceability, and stability during storage of essential oils incorporated in different matrices.