Essential Oils as Antimicrobial Active Substances in Wound Dressings

Structural, mechanical, antioxidant and antibacterial properties of double cross-linked chitosan cryogels as hosts for thymol

The practical applications of essential oils (EOs) are limited by their hydrophobicity, volatility and instability. To overcome these drawbacks, the incorporation of EOs into porous materials is recommended. Chitosan (CS)-based composite cryogels as hosts for thymol as a volatile model terpenoid were developed using a double cross-linking of CS with glutaraldehyde (GA) and monochlorotriazinyl-β-cyclodextrin (MCT-β-CD), either in one-pot synthesis or through sequential cross-linking, first with GA and then with MCT-β-CD, resulting in CSCAV composites. Cross-linking with GA occurred under cryogelation conditions, while cross-linking with MCT-β-CD took place by heating at 60-80 °C. The composite cryogels were characterized by FTIR, 13C NMR, SEM, EDX, swelling kinetics, and uniaxial compressive tests. The mechanical, antioxidant, and antibacterial properties of composites were optimized by adjusting the concentrations of CS and GA, the initial CS to MCT-β-CD ratio, and the temperature regime. The novel CS-based biocomposites demonstrated sustained compression over 74 %, characteristic of porous materials obtained through cryogelation process. The antioxidant activity of the CSCAV composites revealed almost all composites exhibited over 85 % 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity. The thymol-loaded composites displayed strong antibacterial effectiveness (up to 100 %) towards both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria, with greater inhibition activity observed against S. aureus.

Additive Effects of Natural Plant Extracts/Essential Oils and Probiotics as an Antipathogenic Topical Skin Patch Solution for Acne and Eczema

This work leverages the additive antipathogenic effects of natural extracts/essential oils (EOs) and probiotics for the treatment of acne vulgaris associated with Cutibacterium acnes (C. acnes) and eczema complicated by secondary infections with Staphylococcus aureus (S. aureus). Six probiotic strains and various extracts/EOs were evaluated in a large screening to evaluate their potential against both pathogens. Lacticaseibacillus paracasei PCB003 was able to inhibit the growth of both pathogens. For extracts/EOs, Oregano EO had the best antipathogenic effects on both pathogens and did not show any adverse impact on the growth of probiotics, making it suitable for simultaneous use. Using Lactiplantibacillus plantarum PCB011 as a probiotic model, five material formulations were assessed for their suitability to protect probiotic cells within freeze-dried topical patches. Alginate and trehalose (ALG+TRE) and thermoplastic starch (TPS) had the highest probiotic survivability, with ALG+TRE chosen as the final patch material as it was more robust. PCB003 and PCB011 were individually incorporated into the ALG+TRE freeze-dried matrix to form a 6 mm patch; both ALG+TRE (PCB003) and ALG+TRE (PCB011) patches, when used individually, successfully inhibited C. acnes growth by 4.7 and 6.0 mm, respectively, surpassing the performance of commercially available acne patches. The additive effect with 30% Oregano EO further improved pathogen inhibition. For S. aureus, the incorporation of 30% Oregano EO to ALG+TRE (PCB003) increased the size of the inhibition zone more than 10-fold. For C. acnes, the ALG+TRE (PCB003) patch with 30% Oregano EO demonstrated an inhibition zone of 16.3 mm, and the ALG+TRE (PCB011) patch with 30% Oregano EO achieved a 14.3 mm inhibition zone. Genomic analysis confirmed that PCB003 and PCB011 lack antimicrobial resistance determinants, ensuring safety. This study successfully combined probiotics and natural agents to create effective dermatological antipathogenic patches.

Rat model evaluation for healing-promoting effectiveness and antimicrobial activity of electron beam synthesized (polyvinyl alcohol-pectin)- silver doped zinc oxide hydrogel dressings enriched with lavender oil

Ag/ZnO NPs and lavender oil (LVO) were incorporated into (polyvinyl alcohol/pectin) (PVA/Pet) dressings using electron beam irradiation technology. The Ag/ZnO NPs were prepared using the precipitation method and characterized using XRD, FTIR, and EDX techniques. TEM micrograph shows their spherical appearance with an average size of around 27.4 nm. The increase in the (PVA: Pet) feed solution concentration up to 30% enhances the gel content to 92%. The swelling degree reaches 1674% using 80 wt% pectin content. Meanwhile, increasing the irradiation dose up to 45 kGy increases the gel fraction and negatively affects the swelling capabilities. Incorporating Ag/ZnO NPs and LVO slightly decreased the gel fraction, the swelling degree, and the dressing's porosity reached 87%. In pseudo extracellular fluids, dressings with 10% LVO demonstrate 419% swelling capacities, and their WVTR reaches 271.1 g/m2h. Dressings show biocompatibility, antimicrobial potential, and excellent wound healing capacity towards the excisional wound model in rats, as confirmed by the histological and biochemical results. LVO-(PVA/Pet)-Ag/ZnO dressings may accelerate tissue granulation and remodeling by replacing lost collagen and cause the wound to constrict by upregulating markers associated with wound healing so that it can be recommended as a wound healing candidate.

The Influence of Basil and Cinnamon Essential Oils on Bioactive Sponge Composites of Collagen Reinforced with Hydroxyapatite

The increasing prevalence of acute traumas, surgical wounds, and chronic skin wounds poses significant therapeutic challenges for wound treatment. One of the main concerns in wound care is the danger of infection, which is a significant barrier to healing and a cause of higher morbidity and mortality rates. The emergence of drug-resistant bacterial species is becoming more frequent every day. Antimicrobial dressings have become a viable strategy for wound healing and hospital expense savings. Several factors, such as the wound's localization and state, microbial load, and cost, must be considered when choosing an appropriate antimicrobial dressing. One of the key goals of wound care is infection avoidance. This study addresses the therapeutic challenges of acute traumas, surgical wounds, and chronic skin wounds, focusing on infection prevention and combating drug-resistant bacterial strains. The research explores the development of novel composite wound dressings incorporating hydroxyapatite, known for its osteoconductive properties, and essential oils from basil and cinnamon, recognized for their antimicrobial activity. The study evaluates the impact of these additives on key properties such as surface morphology, water absorption, enzymatic degradation, and mechanical performance. Antimicrobial tests showed that two experimental samples (A1S and A1BS) exhibited significant activity against Escherichia coli but not on Staphylococcus aureus. The results highlight the dressings' enhanced antimicrobial properties, mechanical strength, and controlled degradation, making them promising candidates for advanced wound healing. Tailored applications were identified, with each dressing composition offering unique benefits for specific wound-healing scenarios based on the balance between flexibility, structural support, and bioactivity.

Health-Related Messages About Herbs, Spices, and Other Botanicals Appearing in Print Issues and Websites of Legacy Media: Content Analysis and Evaluation

BACKGROUND

Legacy media are publications that existed before the internet. Many of these have migrated to a web format, either replacing or in parallel to their print issues. Readers place an economic value on access to the information presented as they pay for subscriptions and place a higher degree of trust in their content. Much has been written about inaccurate and misleading health information in social media; however, the content and accuracy of information contained in legacy media has not been examined in detail. Discussion of herbs, spices, and other botanicals has been absent from this context.

OBJECTIVE

The objectives of this study were to (1) identify the health associations of botanical products mentioned in legacy media targeted to a range of demographic groups and (2) evaluate these health associations for accuracy against published scientific studies.

METHODS

In total, 10 popular magazines targeting a range of gender, race/ethnicity, and sexual orientation demographic groups were selected for analysis. Relevant content was extracted and coded over 1 year. Associations between specific botanical products and health factors were identified. For the most frequent botanical-health application associations, a PubMed search was conducted to identify reviews corresponding to each item's indicated applications. Where no systematic reviews were available, single research studies were sought.

RESULTS

A total of 237 unique botanical products were identified. There were 128 mentions of these in the print issues and 1215 on the websites. In total, 18 health applications were identified and used to categorize the indicated uses for the various products individually and as general categories. The most frequently mentioned applications were skin care, with 913 mentions, immunity enhancement, with 705 mentions, gastrointestinal health and probiotics, with 184 mentions, and cognitive function (stress and mental health), with 106 mentions. Comparison to published literature evaluating the efficacy of these functions identified positive support for aloe vera, argan oil, chamomile, jojoba oil, lavender, rosemary, and tea tree oil in skin care. Berries, ginger, turmeric, and green tea had the strongest evidence for a role in immunity enhancement. Ginger and oats were supported as having a role in gastrointestinal health. Finally, berries, lavender, ashwagandha, and cannabidiol were supported as having a role in managing stress. Other frequently mentioned items such as aloe vera, ashwagandha, or mushrooms for immunity were less strongly supported.

CONCLUSIONS

Comparison of the most prevalent associations between botanical products and health applications to published literature indicates that, overall, these associations were consistent with current scientific reports about the health applications of botanical products. While some products had a greater degree of research support than others, truly egregious falsehoods were absent. Therefore, legacy media may be considered a credible source of information to readers about these topics.

Essential oils: a potential alternative with promising active ingredients for pharmaceutical formulations in chronic wound management

Chronic wound is a major clinical challenge that complicates wound healing, mainly associated with bacterial biofilms. Bacterial burden damages tissue and persists inflammation, failing to granulate, leading to morbidity and mortality. Various therapeutic strategies and approaches have been developed for chronic wound healing in clinical practice. As treating biofilm infection is crucial in chronic wounds, a potent antibiofilm agent, essential oils have been explored extensively for their therapeutic properties and as a replacement for antibiotic therapy. Currently, several studies on essential oils and their active compounds in therapeutics, such as adjunctive therapies, nanotechnology-based treatment and their drug delivery systems, help heal chronic wounds. The antimicrobial, anti-inflammatory and antioxidant properties of essential oils make them distinct and are renowned as natural remedies to improve the healing of infected chronic wounds. Consequently, it accelerates wound closure by reducing inflammation, increasing angiogenesis and tissue regeneration. This review focuses on different essential oils and their active compounds that are exploited for the treatment of biofilm infection, chronic inflammation and wound healing. Thus, an effective novel treatment can be developed to improve the current treatment strategy to overcome multidrug resistance bacteria or antibiotic resistance in various chronic wound infections that support wound healing.

Antibacterial gelatin/tragacanth gum films containing galbanum essential oil for in vitro scratch-healing

Natural substances and bioactive agents possess great potential in wound care based on their ability to promote healing and prevent infection. This study focused on the fabrication of antibacterial wound dressings by combining gelatin (G), tragacanth gum (TG), and galbanum essential oil (GEO) as a loaded drug. TG addition resulted in more elastic and flexible films besides enabling encapsulation of the hydrophobic GEO into the biopolymeric matrix. GEO was utilized as an antibacterial and a wound-healing enhancer for open wounds such as incisions. Field emission scanning electron microscopy (FE-SEM) analysis revealed a porous film structure after GEO incorporation. Higher GEO concentration caused reduced swelling and slower degradation. Water vapor transfer rate varied from 596 to 894 g/m2.day, making the films suitable for wound dressings. GEO release exhibited a two-phase profile with prolonged diffusion-controlled release for a higher content of GEO. The films demonstrated dose-dependent antimicrobial activity against S. aureus and E. coli strains. Effectiveness and noteworthy application of this research were approved by scratch assay on human dermal fibroblast cells, and films with 3 % GEO showed 79.42 % wound closure, which is significantly higher than the control sample (55.15 %), indicating promoted cell migration and promising wound healing properties.

Enhanced wound healing properties of biodegradable PCL/alginate core-shell nanofibers containing Salvia abrotanoides essential oil and ZnO nanoparticles

Electrospun nanofibrous membranes, with their unique structural features, can potentially enhance wound healing through controlled delivery of active agents. Here, an innovative porous nanofibrous membrane was developed as a dressing patch with antibacterial and anti-inflammatory functionalities for cutaneous wound healing. Zinc oxide nanoparticles (ZnO NPs) and Salvia abrotanoides essential oil (SAEO) were incorporated into sodium alginate, which served as the shell. Poly(ε-caprolactone) was used as the core of coaxial electrospun wound dressing nanofibers (PCL/SA@ZnO/SAEO). With the addition of ZnO NPs and SAEO, the average diameter of nanofibers was 187 ± 51 nm, with improved tensile strength (4.7 ± 0.4 MPa), elongation at break (32.9 ± 2.1), and elastic modulus (21.4 ± 2.0). Concurrent application of ZnO NPs and SAEO increased antimicrobial activity against Staphylococcus aureus and Escherichia coli and promoted the proliferation, attachment, and viability (>90 %) of L929 cells. The PCL/SA@ZnO/SAEO scaffold accelerated the healing time with total wound healing over 14 days in mouse models carrying full-thickness wounds compared to the nanofibrous scaffold without additives. Histopathological examinations demonstrated better tissue regeneration, i.e., enhanced collagen deposition, improved re-epithelialization, and neovascularization, and increased quantity of hair follicles. Moreover, the chicken chorioallantoic membrane assay confirmed the synergistic angiogenic effects of SAEO and ZnO NPs. Finally, the in vitro and in vivo results proposed the bioactive core-shell nanofibers synthesized as encouraging wound dressing materials for hastening the healing of cutaneous wounds.

Essential oils loaded carboxymethylated Cassia fistula gum-based novel hydrogel films for wound healing

Carboxymethylated Cassia fistula gum (CCFG) and citric acid (CA) based wound healing film, (CCFG-CA) was developed using the solvent casting method. Glycerol was added as a plasticizing agent. The synthesized Carboxymethylated Cassia fistula gum cross-linked citric acid based hydrogel film (CCFG-CA) was evaluated morphologically, thermally, and structurally using FESEM, TGA, XRD and FTIR. Three essential oils (EO), rosemary (Rosmarinus officinalis), turmeric (Curcuma longa) and thuja (Thuja occidentalis L), known for antimicrobial and antioxidant activities, were loaded into the CCFG-CA film to develop essential oils loaded carboxymethylated Cassia fistula gum cross-linked citric acid based hydrogel film (CCFG-CA-EO). In vitro studies (MTT assay, disk diffusion assay, permeability tests and DPPH assay) confirm the biocompatibility, anti-oxidant and anti-microbial properties of the CCFG-CA-EO film. In vivo (wound healing studies on wistar rats and their histology) shows 99 % of wound healing and re-epithelialization in 14 days. Degradability (within 15 days), protein adsorption (12.05 μg/mL) and contact angle determination (69.43°ׄׄ ± 0.48) tests confirmed the potential of CCFG-CA-EO as an effective wound-healing material.

Hydrogels with Essential Oils: Recent Advances in Designs and Applications

The innovative fusion of essential oils with hydrogel engineering offers an optimistic perspective for the design and development of next-generation materials incorporating natural bioactive compounds. This review provides a comprehensive overview of the latest advances in the use of hydrogels containing essential oils for biomedical, dental, cosmetic, food, food packaging, and restoration of cultural heritage applications. Polymeric sources, methods of obtaining, cross-linking techniques, and functional properties of hydrogels are discussed. The unique characteristics of polymer hydrogels containing bioactive agents are highlighted. These include biocompatibility, nontoxicity, effective antibacterial activity, control of the sustained and prolonged release of active substances, optimal porosity, and outstanding cytocompatibility. Additionally, the specific characteristics and distinctive properties of essential oils are explored, along with their extraction and encapsulation methods. The advantages and disadvantages of these methods are also discussed. We have considered limitations due to volatility, solubility, environmental factors, and stability. The importance of loading essential oils in hydrogels, their stability, and biological activity is analyzed. This review highlights through an in-depth analysis, the recent innovations, challenges, and future prospects of hydrogels encapsulated with essential oils and their potential for multiple applications including biomedicine, dentistry, cosmetics, food, food packaging, and cultural heritage conservation.

Healing with herbs: an alliance with 'nano' for wound management

INTRODUCTION

Wound healing is an intricate and continual process influenced by numerous factors that necessitate suitable environments to attain healing. The natural ability of wound healing often gets altered by several external and intrinsic factors, leading to chronic wound occurrence. Numerous wound dressings have been developed; however, the currently available alternatives fail to coalesce in all conditions obligatory for rapid skin regeneration.

AREA COVERED

An extensive review of articles on herbal nano-composite wound dressings was conducted using PubMed, Scopus, and Google Scholar databases, from 2006 to 2024. This review entails the pathophysiology and factors leading to non-healing wounds, wound dressing types, the role of herbal bio-actives for wound healing, and the advantages of employing nanotechnology to deliver herbal actives. Numerous nano-composite wound dressings incorporated with phytoconstituents, herbal extracts, and essential oils are discussed.

EXPERT OPINION

There is a strong substantiation that several herbal bio-actives possess anti-inflammatory, antimicrobial, antioxidant, analgesic, and angiogenesis promoter activities that accelerate the wound healing process. Nanotechnology is a promising strategy to deliver herbal bio-actives as it ascertains their controlled release, enhances bioavailability, improves permeability to underlying skin layers, and promotes wound healing. A combination of herbal actives and nano-based dressings offers a novel arena for wound management.

Influence of Lavender Essential Oil on the Physical and Antibacterial Properties of Chitosan Sponge for Hemostatic Applications

Uncontrollable bleeding continues to stand as the primary cause of fatalities globally following surgical procedures, traumatic incidents, disasters, and combat scenarios. The swift and efficient management of bleeding through the application of hemostatic agents has the potential to significantly reduce associated mortality rates. One significant drawback of currently available hemostatic products is their susceptibility to bacterial infections at the bleeding site. As this is a prevalent issue that can potentially delay or compromise the healing process, there is an urgent demand for hemostatic agents with antibacterial properties to enhance survival rates. To mitigate the risk of infection at the site of a lesion, we propose an alternative solution in the form of a chitosan-based sponge and antimicrobial agents such as silver nanoparticles (AgNPs) and lavender essential oil (LEO). The aim of this work is to provide a new type of hemostatic sponge with an antibacterial barrier against a wide range of Gram-positive and Gram-negative microorganisms: Staphylococcus epidermidis 2018 and Enterococcus faecalis VRE 2566 (Gram-positive strains) and Klebsiella pneumoniae ATCC 10031 and Escherichia coli ATCC 35218 (Gram-negative strains).

Antimicrobial Wound Dressings based on Bacterial Cellulose and Independently Loaded with Nutmeg and Fir Needle Essential Oils

The aim of the present study was to obtain antimicrobial dressings from bacterial cellulose loaded with nutmeg and of fir needle essential oils. The attractive properties of BC, such as biocompatibility, good physicochemical and mechanical stability, and high water absorption, led to the choice of this material to be used as a support. Essential oils have been added to provide antimicrobial properties to these dressings. The results confirmed the presence of oils in the structure of the bacterial cellulose membrane and the ability of the materials to inhibit the adhesion of Staphylococcus aureus and Escherichia coli. By performing antibacterial tests on membranes loaded with fir needle essential oil, we demonstrated the ability of these membranes to inhibit bacterial adhesion to the substrate. The samples loaded with nutmeg essential oil exhibited the ability to inhibit the adhesion of bacteria to the surface of the materials, with the 5% sample showing a significant decrease. The binding of essential oils to the membrane was confirmed by thermal analysis and infrared characterization.

Aromatherapeutic and Antibacterial Properties of Cotton Materials Treated with Emulsions Containing Peppermint Essential Oil (Menthae piperitae aetheroleum)

The objective of the work was to obtain materials with aromatherapeutic and antibacterial properties by applying emulsions based on peppermint essential oil (PEO) onto cotton fabric. For this purpose, some emulsions based on PEO incorporated in various matrices (chitosan + gelatin + beeswax; chitosan + beeswax; gelatin + beeswax and gelatin + chitosan) were prepared. Tween 80 was used as a synthetic emulsifier. The influence of the nature of matrices and of the concentration of Tween 80 on the stability of the emulsions was evaluated by the creaming indices. The materials treated with the stable emulsions were analyzed in terms of sensory activity, of the comfort characteristics, and of the gradual release of the PEO in the artificial perspiration solution. The sum of volatile components retained by samples after exposure to air was determined by GC-MS. The results regarding antibacterial activity showed that materials treated with emulsions have a good inhibitory effect on S. aureus (diameters of the inhibition zones between 53.6 and 64.0 mm) and on E. coli (diameters of the inhibition zones between 38.3 and 64.0 mm). Our data suggest that by applying peppermint-oil-based emulsions on a cotton support, aromatherapeutic patches, bandages and dressings with antibacterial properties can be obtained.

Wound Dressing Modifications for Accelerated Healing of Infected Wounds

Infections that occur during wound healing involve the most frequent complications in the field of wound care which not only inhibit the whole process but also lead to non-healing wound formation. The diversity of the skin microbiota and the wound microenvironment can favor the occurrence of skin infections, contributing to an increased level of morbidity and even mortality. As a consequence, immediate effective treatment is required to prevent such pathological conditions. Antimicrobial agents loaded into wound dressings have turned out to be a great option to reduce wound colonization and improve the healing process. In this review paper, the influence of bacterial infections on the wound-healing phases and promising modifications of dressing materials for accelerated healing of infected wounds are discussed. The review paper mainly focuses on the novel findings on the use of antibiotics, nanoparticles, cationic organic agents, and plant-derived natural compounds (essential oils and their components, polyphenols, and curcumin) to develop antimicrobial wound dressings. The review article was prepared on the basis of scientific contributions retrieved from the PubMed database (supported with Google Scholar searching) over the last 5 years.

Revisiting the Therapeutic Effects of Essential Oils on the Oral Microbiome

The extensive use of antibiotics has resulted in the development of drug-resistant bacteria, leading to a decline in the efficacy of traditional antibiotic treatments. Essential oils (EOs) are phytopharmaceuticals, or plant-derived compounds, that possess beneficial properties such as anti-inflammatory, antibacterial, antimicrobial, antiviral, bacteriostatic, and bactericidal effects. In this review, we present scientific findings on the activity of EOs as an alternative therapy for common oral diseases. This narrative review provides a deeper understanding of the medicinal properties of EOs and their application in dentistry. It not only evaluates the effectiveness of these oils as antibacterial agents against common oral bacteria but also covers general information such as composition, methods of extraction, and potential toxicity. Further nonclinical and clinical studies must be conducted to determine their potential use and safety for treating oral diseases.

Antimicrobial Natural Hydrogels in Biomedicine: Properties, Applications, and Challenges-A Concise Review

Natural hydrogels are widely used as biomedical materials in many areas, including drug delivery, tissue scaffolds, and particularly wound dressings, where they can act as an antimicrobial factor lowering the risk of microbial infections, which are serious health problems, especially with respect to wound healing. In this review article, a number of promising strategies in the development of hydrogels with biocidal properties, particularly those originating from natural polymers, are briefly summarized and concisely discussed. Common strategies to design and fabricate hydrogels with intrinsic or stimuli-triggered antibacterial activity are exemplified, and the mechanisms lying behind these properties are also discussed. Finally, practical antibacterial applications are also considered while discussing the current challenges and perspectives.