Antioxidant, Antifungal, Antibiofilm, and Cytotoxic Activities of Mentha spp. Essential Oils

Biocontrol Mechanisms of Three Plant Essential Oils Against Phytophthora infestans Causing Potato Late Blight

Late blight, caused by the notorious pathogen Phytophthora infestans, poses a significant threat to potato (Solanum tuberosum) crops worldwide, impacting their quality as well as yield. Here, we aimed to investigate the potential use of cinnamaldehyde, carvacrol, and eugenol as control agents against P. infestans and to elucidate their underlying mechanisms of action. To determine the pathogen-inhibiting concentrations of these three plant essential oils (PEOs), a comprehensive evaluation of their effects using gradient dilution, mycelial growth rate, and spore germination methods was carried out. Cinnamaldehyde, carvacrol, and eugenol were capable of significantly inhibiting P. infestans by hindering its mycelial radial growth, zoospore release, and sporangium germination; the median effective inhibitory concentration of the three PEOs was 23.87, 8.66, and 89.65 μl/liter, respectively. Scanning electron microscopy revealed that PEOs caused the irreversible deformation of P. infestans, resulting in hyphal shrinkage, distortion, and breakage. Moreover, propidium iodide staining and extracellular conductivity measurements demonstrated that all three PEOs significantly impaired the integrity and permeability of the pathogen's cell membrane in a time- and dose-dependent manner. In vivo experiments confirmed the dose-dependent efficacy of PEOs in reducing the lesion diameter of potato late blight. Altogether, these findings provide valuable insight into the antifungal mechanisms of PEOs vis-à-vis late blight-causing P. infestans. By utilizing the inherent capabilities of these natural compounds, we could effectively limit the harmful impacts of late blight on potato crops, thereby enhancing agricultural practices and ensuring the resilience of global potato food production.

Bioactive Phyto-Compounds with Antimicrobial Effects and AI: Results of a Desk Research Study

Resistance of microorganisms to antibiotics represents a formidable global challenge, manifesting in intricate public health ramifications including escalated mortality rates and augmented healthcare costs. The current efforts to manage antimicrobial resistance (AMR) are limited mainly to the standard therapeutic approaches. The aim of this study is to present and analyze the role of artificial intelligence (AI) in the search for new phyto-compounds and novel interactions with antimicrobial effects. The ambition of the current research study is to support researchers by providing summarized information and ideas for future research in the battle with AMR. Inevitably, the AI role in healthcare is growing exponentially. The reviewed AI models reveal new data on essential oils (EOs) as potential therapeutic agents. In terms of antibacterial activity, EOs show activity against MDR bacteria, reduce resistance by sensitizing bacteria to the action of antibiotics, and improve therapeutic efficiency when combined with antibiotics. AI models can also serve for the detailed study of other therapeutic applications of EOs such as respiratory diseases, immune diseases, neurodegenerative diseases, and oncological diseases. The last 5 years have seen an increasing application of AI in the search for potential plant sources to control AMR. For the time being, the application of machine-learning (ML) models is greater in the studies of EOs. Future attention of research teams may also be directed toward a more efficient search for plant antimicrobial peptides (PAMPs). Of course, investments in this direction are a necessary preface, but the excitement of new possibilities should not override the role of human intelligence in directing research processes. In this report, tradition meets innovation to address the "silent pandemic" of AMR.

Antibacterial and Antiviral Properties of Pinus densiflora Essential Oil

The Korean mountains are home to the Korean red pine (Pinus densiflora). Pine needle oil has been used as a food additive and a traditional herbal medicine; however, any health-related properties of its trunk oil remain unknown. Herein, we assessed antibacterial and antiviral properties of essential oil extracted from the trunk of P. densiflora. Th extracted oil was hydrodistilled using a Clevenger apparatus and analyzed using gas chromatography-mass spectrometry. The antimicrobial activity of the oil was tested using the microbroth dilution technique against 10 bacterial species (6 g-positive and 4 g-negative) and fungi. The extract exerted strong antimicrobial activity against Vibrio parahaemolyticus, Bacillus cereus, Listeria monocytogenes, Propionibacterium acnes, and Malassezia furfur (minimum inhibitory concentration = 10 mL/L). Additionally, it exhibited dose-dependent activity against influenza virus A and feline coronavirus. Furthermore, among 20 identified constituents accounting for 98.7% of the oil contents, the major components included 3-cyclohexene-1-methanol (10.12%), 2-(4-methylcyclohexyl)-2-propanol (9.09%), fenchone (8.14%), O-isopropyltoluene (6.35%), and isothymol methyl ether (6.14%). The P. densiflora trunk essential oil showed antibacterial and antiviral activities that depended on its chemical composition and the microbial strains tested herein. The essential oil can be used as an antimicrobial agent and disinfectant.

Natural Compounds with Antifungal Properties against Candida albicans and Identification of Hinokitiol as a Promising Antifungal Drug

Candida albicans is an opportunistic yeast that causes most fungal infections. C. albicans has become increasingly resistant to antifungal drugs over the past decade. Our study focused on the identification of pure natural compounds for the development of antifungal medicines. A total of 15 natural compounds from different chemical families (cinnamic derivatives, aromatic phenols, mono- and sesquiterpenols, and unclassified compounds) were screened in this study. Among these groups, hinokitiol (Hi), a natural monoterpenoid extracted from the wood of the cypress family, showed excellent anti-C. albicans activity, with a MIC value of 8.21 µg/mL. Hi was selected from this panel for further investigation to assess its antifungal and anti-inflammatory properties. Hi exhibited significant antifungal activity against clinically isolated fluconazole- or caspofungin-resistant C. albicans strains. It also reduced biofilm formation and hyphal growth. Treatment with Hi protected Caenorhabditis elegans against infection with C. albicans and enhanced the expression of antimicrobial genes in worms infected with C. albicans. Aside from its antifungal activities against C. albicans, Hi challenge attenuated the LPS-induced expression of pro-inflammatory cytokines (IL-6, IL-1β, and CCL-2) in macrophages. Overall, Hi is a natural compound with antifungal and anti-inflammatory properties, making Hi a promising platform with which to fight against fungal infections.

Encapsulation of mint essential oil: Techniques and applications

Mint essential oil (MEO) is an outstanding antibacterial and antioxidant agent, that can be considered as a promising natural preservative, flavor, insecticide, coolant, and herbal medicine. However, the low solubility and volatility of MEO limits its extensive applications. In order to utilize MEO in different products, it is essential to develop treatments that can overcome these limitations. More recently, encapsulation technology has been developed as a promising method to overcome the shortcomings of MEO. In which, sensitive compounds such as essential oils (EOs) are entrapped in a carrier to produce micro or nanoparticles with increased stability against environmental conditions. Additionally, encapsulation of EOs makes transportation and handling easier, reduces their volatility, controls their release and consequently improves the efficiency of these bioactive compounds and extends their industrial applications. Several encapsulation techniques, such as emulsification, coacervation, ionic gelation, inclusion complexation, spray drying, electrospinning, melt dispersion, melt homogenization, and so on, have been emerged to improve the stability of MEO. These encapsulated MEOs can be also used in a variety of food, bioagricultural, pharmaceutical, and health care products with excellent performance. Therefore, this review aims to summarize the physicochemical and functional properties of MEO, recent advances in encapsulation techniques for MEO, and the application of micro/nanocapsulated MEO in different products.

Pleiotropic effects of Mentha longifolia L. extract on the regulation of genes involved in inflammation and apoptosis induced by Clostridioides difficile ribotype 001

Introduction

The dramatic increase in multidrug-resistance of Clostridioides difficile isolates has led to the search for new complementary medicines against C. difficile infection (CDI). In this study, we aimed to examine the inhibitory effects of hydroethanolic extract of Mentha longifolia L. (ETOH-ML) on the growth of C. difficile RT001 and its toxigenic cell-free supernatant (Tox-S)-induced inflammation and apoptosis.

Methods

The active phytochemical components of ETOH-ML were detected using GC and HPLC. The antimicrobial properties of the extract were examined against C. difficile RT001. Furthermore, cell viability and cytotoxicity of Caco-2 and Vero cells treated with various concentrations of ETOH-ML, Tox-S of C. difficile RT001, and their combination were assessed. Anti-inflammatory and anti-apoptotic activities of ETOH-ML were explored in Tox-S stimulated Caco-2 cells using RT-qPCR.

Results

Based on our results, rosmarinic acid was the main phytochemical component of ETOH-ML. The extract showed significant antimicrobial activity against C. difficile RT001 by agar dilution and broth microdilution methods. Moreover, ETOH-ML at concentrations of <25 μg/ml had no significant effect on cell viability compared to untreated cells. Treatment cells with the extract (10 or 25 μg/ml) significantly increased the cell viability and reduced the percentage of cell rounding in Caco-2 and Vero cells treated by Tox-S, respectively (P < 0.0001). Co-treatment of Tox-S stimulated Caco-2 cells with ETOH-ML showed significant anti-inflammatory and anti-apoptotic activities by downregulating the gene expression level of IL-8, IL-1β, TNF-α, iNOS, TGF-β, NF-κB, Bax, and caspase-3, while upregulating the expression level of Bcl-2.

Discussion

Our results demonstrated for the first time the antimicrobial, anti-inflammatory, and anti-apoptotic effects of M. longifolia extract on C. difficile RT001 and its Tox-S. However, further research is needed to evaluate the potential application of M. longifolia extract on CDI treatment in clinical setting.

Chemical Composition of Litsea pungens Essential Oil and Its Potential Antioxidant and Antimicrobial Activities

Litsea pungens is a plant with medicinal and edible properties, where the fruits are edible and the leaves have medicinal properties. However, there is limited research on the chemical and pharmacological activities of the plant. In this study, essential oils were extracted by steam distillation and their antioxidant and antibacterial activities were further evaluated. Gas chromatography-mass spectrometry (GC-MS) was used to identify the chemical components of L. pungens fresh fruit essential oil (FREO) and L. pungens fresh flower essential oil (FLEO), rapeseed oil (RO) and commercial Litsea oil (CEO). The results showed that 12 chemical components were identified in FREO. Twelve chemical components were identified from FLEO, four chemical components were identified from CEO, and thirteen chemical components were identified from RO. Except for RO, the other three oils were mainly composed of terpenes, among which limonene is the main chemical component. In terms of antioxidant activity, FREO, FLEO, CEO and RO have antioxidant capacity, mainly reflected in the scavenging DPPH free radicals and the iron ion chelating ability, and the antioxidant activity shows a certain dose effect, but the antioxidant activity of FLEO is the weakest among the four oils. Meanwhile, under the stress of hydrogen peroxide, CEO demonstrated a significant antioxidant protective effect on cells. It is worth mentioning that compared with the positive control, the FREO exhibited a better antibacterial rate. When the concentration of essential oil is 20 mg/mL, the bacteriostatic rate can reach 100%. Therefore, it could be a promising candidate among medicinal and edible plants.

Antibacterial and Antibiofilm Effects of Different Samples of Five Commercially Available Essential Oils

Essential oils (EOs) have gained economic importance due to their biological activities, and increasing amounts are demanded everywhere. However, substantial differences between the same essential oil samples from different suppliers are reported-concerning their chemical composition and bioactivities-due to numerous companies involved in EOs production and the continuous development of online sales. The present study investigates the antibacterial and antibiofilm activities of two to four samples of five commercially available essential oils (Oregano, Eucalyptus, Rosemary, Clove, and Peppermint oils) produced by autochthonous companies. The manufacturers provided all EOs' chemical compositions determined through GC-MS. The EOs' bioactivities were investigated in vitro against Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). The antibacterial and antibiofilm effects (ABE% and, respectively, ABfE%) were evaluated spectrophotometrically at 562 and 570 nm using microplate cultivation techniques. The essential oils' calculated parameters were compared with those of three standard broad-spectrum antibiotics: Amoxicillin/Clavulanic acid, Gentamycin, and Streptomycin. The results showed that at the first dilution (D1 = 25 mg/mL), all EOs exhibited antibacterial and antibiofilm activity against all Gram-positive and Gram-negative bacteria tested, and MIC value > 25 mg/mL. Generally, both effects progressively decreased from D1 to D3. Only EOs with a considerable content of highly active metabolites revealed insignificant differences. E. coli showed the lowest susceptibility to all commercially available essential oils-15 EO samples had undetected antibacterial and antibiofilm effects at D2 and D3. Peppermint and Clove oils recorded the most significant differences regarding chemical composition and antibacterial/antibiofilm activities. All registered differences could be due to different places for harvesting the raw plant material, various technological processes through which these essential oils were obtained, the preservation conditions, and complex interactions between constituents.

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.

The Anti-Biofilm Potential of Linalool, a Major Compound from Hedychium larsenii, against Streptococcus pyogenes and Its Toxicity Assessment in Danio rerio

The anti-biofilm and anti-virulence potential of the essential oil (E.O.) extracted from Hedychium larsenii M. Dan & Sathish was determined against Streptococcus pyogenes. A crystal violet assay was employed to quantify the biofilm. Linalool, a monoterpene alcohol from the E.O., showed concentration-dependent biofilm inhibition, with a maximum of 91% at a concentration of 0.004% (v/v). The AlamarBlueTM assay also confirmed Linalool’s non-bactericidal anti-biofilm efficacy (0.004%). Linalool treatment impeded micro-colony formation, mature biofilm architecture, surface coverage, and biofilm thickness and impaired cell surface hydrophobicity and EPS production. Cysteine protease synthesis was quantified using the Azocasein assay, and Linalool treatment augmented its production. This suggests that Linalool destabilizes the biofilm matrix. It altered the expression of core regulons covRS, mga, srv, and ropB, and genes associated with virulence and biofilm formation, such as speB, dltA, slo, hasA, and ciaH, as revealed by qPCR analysis. Cytotoxicity analysis using human kidney cells (HEK) and the histopathological analysis in Danio rerio proved Linalool to be a druggable molecule against the biofilms formed by S. pyogenes. This is the first report on Linalool’s anti-biofilm and anti-virulence potential against S. pyogenes.

In Vitro Antiviral Potential, Antioxidant, and Chemical Composition of Clove (Syzygium aromaticum) Essential Oil

Viral infections are spread all around the world. Although there are available therapies, their safety and effectiveness are constrained by their adverse effects and drug resistance. Therefore, new natural antivirals have been used such as essential oils, which are natural products with promising biological activity. Accordingly, the present study aimed to identify the components of clove (Syzygium aromaticum) essential oil (EOCa) and verify its antioxidant and antiviral activity. The oil was analyzed using GC/MS, and the antioxidant capacity was evaluated as a function of the radical scavenging activity. A plaque reduction test was used to measure the antiviral activity against herpes simplex virus (HSV-1), hepatitis A virus (HAV), and an adenovirus. GC/MS analysis confirmed the presence of eugenol as the main component (76.78%). Moreover, EOCa had powerful antioxidant activity with an IC50 of 50 µg/mL. The highest antiviral potential was found against HAV, with a selectivity index (SI) of 14.46, while showing poor selectivity toward HSV-1 with an SI value of 1.44. However, no relevant effect was detected against the adenovirus. The antiviral activity against HAV revealed that its effect was not related to host cytotoxicity. The findings imply that EOCa can be utilized to treat diseases caused by infections and free radicals.

Evaluation of In Vitro and In Silico Anti-Alzheimer Potential of Nonpolar Extracts and Essential Oil from Mentha piperita

The anticholinesterase and antioxidant activities with chemical composition and molecular docking of essential oil and nonpolar extracts of Mentha piperita were evaluated using enzymatic and chemical methods. Molecular docking tools were used to explain the interaction of the major chemical constituents with the enzymes. GC/MS analyses revealed that the main compounds in M. piperita essential oil were l-menthone (43.601%) followed by pulegone (21.610%), linolenic acid (25.628%), and l-menthone (10.957%), representing the major compounds of the petroleum ether extract. Imidazoquinoline (7.767%) and 17-N-acetyl-oroidine (5.363%) were the major constituents of the chloroform extract. Linolenic acid (19.397%) and l-menthone (6.336%) were the most abundant compounds in the hexane extract. The M. piperita essential oil and nonpolar extracts showed moderate antioxidant activity. The essential oil showed the most promising anticholinesterase activity with IC₅₀ = 10.66 ± 0.12 µg/mL and IC₅₀ = 16.33 ± 0.03 µg/mL against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), respectively, close to galantamine in AChE and more active in BChE, followed by the interesting activity in the petroleum ether extract with IC₅₀ = 23.42 ± 3.06 µg/mL in AChE and IC₅₀ = 62.00 ± 3.22 µg/mL in BChE. The docking experiments showed that among the seven major identified compounds, N-acetyl-17-oroidine showed the highest binding score (63.01 in AChE and 63.68 in BChE). This compound was found to bind the catalytic and peripheral sites, resulting in more potent inhibitory activity than galantamine, which only binds to the catalytic site. These findings suggested the possible use of M. piperita essential oil and nonpolar extracts as a potential source of alternative natural anti-Alzheimer compounds.

Chemical and Antimicrobial Characterization of Mentha piperita L. and Rosmarinus officinalis L. Essential Oils and In Vitro Potential Cytotoxic Effect in Human Colorectal Carcinoma Cells

Colorectal cancer is one of the most frequently diagnosed forms of cancer, and the therapeutic solutions are frequently aggressive requiring improvements. Essential oils (EOs) are secondary metabolites of aromatic plants with important pharmacological properties that proved to be beneficial in multiple pathologies including cancer. Mentha piperita L. (M_EO) and Rosmarinus officinalis L. (R_EO) essential oils are well-known for their biological effects (antimicrobial, antioxidant, anti-inflammatory and cytotoxic in different cancer cells), but their potential as complementary treatment in colorectal cancer is underexplored. The aim of the present study was to investigate the M_EO and R_EO in terms of chemical composition, antioxidant, antimicrobial, and cytotoxic effects in a colorectal cancer cell line—HCT 116. The gas-chromatographic analysis revealed menthone and menthol, and eucalyptol, α-pinene and L-camphor as major compounds in M_EO and R_EO respectively. M_EO exhibited potent antimicrobial activity, moderate antioxidant activity and a low cytotoxic effect in HCT 116 cells. R_EO presented a significant cytotoxicity in colorectal cancer cells and a low antimicrobial effect. The cytotoxic effect on non-cancerous cell line HaCaT was not significant for both essential oils. These results may provide an experimental basis for further research concerning the potential use of M_EO and R_EO for anticancer treatment.

Current Knowledge on Biomaterials for Orthopedic Applications Modified to Reduce Bacterial Adhesive Ability

A significant challenge in orthopedics is the design of biomaterial devices that are able to perform biological functions by substituting or repairing various tissues and controlling bone repair when required. This review presents an overview of the current state of our recent research into biomaterial modifications to reduce bacterial adhesive ability, compared with previous reviews and excellent research papers, but it is not intended to be exhaustive. In particular, we investigated biomaterials for replacement, such as metallic materials (titanium and titanium alloys) and polymers (ultra-high-molecular-weight polyethylene), and biomaterials for regeneration, such as poly(ε-caprolactone) and calcium phosphates as composites. Biomaterials have been designed, developed, and characterized to define surface/bulk features; they have also been subjected to bacterial adhesion assays to verify their potential capability to counteract infections. The addition of metal ions (e.g., silver), natural antimicrobial compounds (e.g., essential oils), or antioxidant agents (e.g., vitamin E) to different biomaterials conferred strong antibacterial properties and anti-adhesive features, improving their capability to counteract prosthetic joint infections and biofilm formation, which are important issues in orthopedic surgery. The complexity of biological materials is still far from being reached by materials science through the development of sophisticated biomaterials. However, close interdisciplinary work by materials scientists, engineers, microbiologists, chemists, physicists, and orthopedic surgeons is indeed necessary to modify the structures of biomaterials in order to achieve implant integration and tissue regeneration while avoiding microbial contamination.

Essential oil for the control of fungi, bacteria, yeasts and viruses in food: an overview

This review begins with a general introduction to essential oils (EO) and their relation to food and microorganisms. Classification and characteristics of EO, addressing the major compounds with antimicrobial action. Subsequently, the main microorganisms followed by a collection of the main works published in recent years that approached the influence of the EO on the protection against microorganisms and food decontamination. At last, the major gaps and future perspectives on the subject. Using EO for fighting food contamination is a way of sustainably supplying the need for new antimicrobials to ensure microbial safety and is a viable source to solve the problem of current microbial resistance. Form of application, EO composition and microbiological load are reported as the responsible factors for the treatment's success. The EO's effects on fungi and bacteria are already well known, but its effect on viruses and yeasts is something to be explored.

Antibacterial and Antioxidant Activity of Dysphania ambrosioides (L.) Mosyakin and Clemants Essential Oils: Experimental and Computational Approaches

Dysphania ambrosioides (L.) Mosyakin and Clemants, also known as Mexican tea, and locally known as Mkhinza, is a polymorphic annual and perennial herb, and it is widely used in folk medicine to treat a broad range of illnesses in Morocco. The aim of this study was to determine the phytochemical content and the antioxidant and the antibacterial properties of essential oils isolated from D. ambrosioides aerial components, growing in Eastern Morocco (Figuig). Hydrodistillation was used to separate D. ambrosioides essential oils, and the abundance of each phytocompound was determined by using Gas Chromatography coupled with Mass Spectrometry (GC–MS). In vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and inhibition of β-carotene/linoleic acid bleaching assays were used to determine D. ambrosioides essential oils’ antioxidant activity. The findings revealed relative antioxidative power and modest radical scavenging. The antibacterial activity of the essential oils was broad-spectrum, with Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis as the most susceptible strains tested. To elucidate the physicochemical nature, drug-likeness, and the antioxidant and antibacterial action of the identified phytocomponents, computational techniques, such as ADMET analysis, and molecular docking were used.

Peppermint oil effects on the gut microbiome in children with functional abdominal pain

Peppermint oil (PMO) is effective in the treatment of functional abdominal pain disorders, but its mechanism of action is unclear. Evidence suggests PMO has microbicidal activity. We investigated the effect of three different doses of PMO on gut microbiome composition. Thirty children (7-12 years of age) with functional abdominal pain provided a baseline stool sample prior to randomization to 180, 360, or 540 mg of enteric coated PMO (10 participants per dose). They took their respective dose of PMO (180 mg once, 180 mg twice, or 180 mg thrice daily) for 1 week, after which the stool collection was repeated. Baseline and post-PMO stools were analyzed for microbiome composition. There was no difference in alpha diversity of the gut microbiome between the baseline and post-PMO treatment. Principal coordinate analysis revealed no significant difference in overall bacterial composition between baseline and post-PMO samples, as well as between the PMO dose groups. However, the very low abundant Collinsella genus and three operational taxonomic units (one belonging to Collinsella) were significantly different in samples before and after PMO treatment. The Firmicutes/Bacteroidetes ratio was lower in children who received 540 mg of PMO compared to the 180 mg and 360 mg dose groups (p = 0.04). Network analysis revealed separation between pre- and post-PMO fecal samples with the genus Collinsella driving the post-PMO clusters. PMO administration appeared to impact only low abundance bacteria. The 540 mg PMO dose differentially impacted the Firmicutes/Bacteroidetes ratio. A higher dose and/or longer duration of treatment might yield different results.

Mentha arvensis Essential Oil Exerts Anti-Inflammatory in LPS-Stimulated Inflammatory Responses via Inhibition of ERK/NF-κB Signaling Pathway and Anti-Atopic Dermatitis-like Effects in 2,4-Dinitrochlorobezene-Induced BALB/c Mice

The mechanism of atopic dermatitis (AD) is modulated by the release of cytokines and chemokines through the mitogen-activated protein kinase (MAPK)/nuclear factor-kappa B (NF-κB) signaling pathway. Topical steroids are used to treat AD, but some people need safer anti-inflammatory drugs to avoid side effects. Mentha arvensis has been used as a herbal plant with medicinal properties, but its anti-inflammatory effects have not been elucidated in an AD model. In this study, we investigated the anti-inflammatory effects of M. arvensis essential oil (MAEO) and its underlying molecular mechanism in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and HaCaT cells (human epidermal keratinocyte). Additionally, we examined the ameliorating effects of the MAEO in a dinitrochlorobenzene (DNCB)-induced murine model of AD. We found, in both RAW 264.7 cells and HaCaT cells, MAEO inhibited LPS-stimulated inflammatory mediators such as nitric oxide (NO) and prostaglandin E₂ and proinflammatory cytokines, including IL-1β and IL-6, due to the suppression of COX-2 and iNOS expression. In LPS-stimulated macrophages, we also observed that MAEO inhibited the phosphorylation of ERK and P65. Furthermore, MAEO treatment attenuated AD symptoms, including the dermatitis score, ear thickness, epidermal thickness and infiltration of mast cells, in a DNCB-induced animal model of AD. Overall, our findings suggest that MAEO exerts anti-inflammatory and anti-atopic dermatitis effects via inhibition of the ERK/NF-κB signaling pathway.

Fungal Biofilms as a Valuable Target for the Discovery of Natural Products That Cope with the Resistance of Medically Important Fungi-Latest Findings

The development of new antifungal agents that target biofilms is an urgent need. Natural products, mainly from the plant kingdom, represent an invaluable source of these entities. The present review provides an update (2017-May 2021) on the available information on essential oils, propolis, extracts from plants, algae, lichens and microorganisms, compounds from different natural sources and nanosystems containing natural products with the capacity to in vitro or in vivo modulate fungal biofilms. The search yielded 42 articles; seven involved essential oils, two Brazilian propolis, six plant extracts and one of each, extracts from lichens and algae/cyanobacteria. Twenty articles deal with the antibiofilm effect of pure natural compounds, with 10 of them including studies of the mechanism of action and five dealing with natural compounds included in nanosystems. Thirty-seven manuscripts evaluated Candida spp. biofilms and two tested Fusarium and Cryptococcus spp. Only one manuscript involved Aspergillus fumigatus. From the data presented here, it is clear that the search of natural products with activity against fungal biofilms has been a highly active area of research in recent years. However, it also reveals the necessity of deepening the studies by (i) evaluating the effect of natural products on biofilms formed by the newly emerged and worrisome health-care associated fungi, C. auris, as well as on other non-albicans Candida spp., Cryptococcus sp. and filamentous fungi; (ii) elucidating the mechanisms of action of the most active natural products; (iii) increasing the in vivo testing.

Anethum Graveolens Essential Oil Nanoemulsions (AGEO-NE) as an Exclusive Apoptotic Inducer in Human Lung Adenocarcinoma (A549) Cells

Anethum graveolens essential oil (AGEO) is used as an anticancer compound that can be made more efficacious by improving its biosolubility and biocompatibility. In the current study, we aimed to improve AGEO bioactivity using the nanoemulsion-based encapsulation technique. To formulate stable AGEO-NE, an ultrasonication method was utilized. The size, stability, and morphology of the AGEO-NE was measured, and then its cytotoxic impacts were evaluated on adenocarcinomic human alveolar basal epithelial cells (A549). The ferric reducing antioxidant power (FRAP) test was done to measure the antioxidant activity of AGEO-NE. Its cytotoxic property was analyzed by measuring the viability percentage of cancer (A549) and normal human foreskin fibroblast (HFF) cell lines after increasing AGEO-NE treatment doses. AGEO-NE apoptotic activity was evaluated by studying the flow cytometry of the cells and measuring the apoptotic gene expression profile (Cas-3 and Cas-8) in the A549 cell line. The results showed a significant correlation between the increase of AGEO-NE concentrations and decrease of cancer (A549) cell viability (p < 0.05) when AGEO-NE was compared with normal HFF cells. Thus, AGEO-NE can be an efficient novel apoptosis and antioxidant inducer for human lung cancer cells without any undesirable side effects. However, further In Vitro and In Vivo studies are needed to confirm the results.

Culinary and nutritional value of edible wild plants from northern Spain rich in phenolic compounds with potential health benefits

Wild edible plants (WEPs) have been consumed since ancient times. They are considered as non-domesticated plants that grow spontaneously in nature, particularly in forests and bushlands, where they can be found and collected to be incorporated into human nutrition. Increasingly, WEPs are gaining importance as they are potential sources of food due to their nutritional value, besides showing positive health effects and offer innovative applications in haute cuisine. As these autochthonous plants grow naturally in the environment, they are more suitable to adapt to different climatic conditions as well as biotic and abiotic factors. Therefore, a door has been opened for their possible cultivation as they seem to require fewer expenses than other commercially cultivated plants. Moreover, the consumers demand for new products of natural origin that are sustainable and ecologically labeled have also boosted WEPs' recovery and incorporation into the market. In addition, they are considered as promising sources of essential compounds needed not only in human diet including carbohydrates, proteins, and lipids but also of other minor compounds as phenols, vitamins, or carotenoids that have shown numerous beneficial bioactivities such as antioxidants, anti-inflammatory, or anti-tumor activity. The use of these plants rich in bioactive molecules could be beneficial from the health point of view as the human body is not always capable of producing enough defenses, for instance, preventing oxidative damage. In particular, the presence of phenolic compounds in these vegetal matrices is supposed to provide a prophylactic effect against further pathogenesis and disorders related to aging or oxidative stresses. Regarding all this information based on traditional knowledge and ethnobotanical data, different WEPs found in the Northwestern region of Spain were selected, namely, Mentha suaveolens, Glechoma hederacea, Prunus spinosa, Apium nodiflorum, Artemisia absinthium, Silybum marianum, Picris hieracioides, Portulaca oleracea, Crithmum maritimum, and the genus Amaranthus. However, even though tradition and popular knowledge are excellent tools for the exploitation of these plants, it is necessary to develop regulations in this aspect to assure safety and veracity of food products. This article aims to review the main aspects of their bioactive properties, their traditional use, and the possibility of their incorporation into the market as new functional foods, looking at innovative and healthy gastronomic applications.

Polymeric Carriers Designed for Encapsulation of Essential Oils with Biological Activity

The article reviews the possibilities of encapsulating essential oils EOs, due to their multiple benefits, controlled release, and in order to protect them from environmental conditions. Thus, we present the natural polymers and the synthetic macromolecular chains that are commonly used as networks for embedding EOs, owing to their biodegradability and biocompatibility, interdependent encapsulation methods, and potential applicability of bioactive blend structures. The possibilities of using artificial intelligence to evaluate the bioactivity of EOs—in direct correlation with their chemical constitutions and structures, in order to avoid complex laboratory analyses, to save money and time, and to enhance the final consistency of the products—are also presented.

Activity of Liquid and Volatile Fractions of Essential Oils against Biofilm Formed by Selected Reference Strains on Polystyrene and Hydroxyapatite Surfaces

Biofilms are surface-attached, structured microbial communities displaying higher tolerance to antimicrobial agents in comparison to planktonic cells. An estimated 80% of all infections are thought to be biofilm-related. The drying pipeline of new antibiotics efficient against biofilm-forming pathogens urges the search for alternative routes of treatment. Essential Oils (EOs), extracted from medicinally important plants, are a reservoir of bioactive compounds that may serve as a foothold in investigating novel antibiofilm compounds. The aim of this study was to compare antimicrobial activity of liquid and volatile fractions of tested EOs against biofilm-forming pathogens using different techniques. In this research, we tested five EOs, extracted from Syzygium aromaticum L., Boswelia serrata Roxb., Juniperus virginiana L., Pelargonium graveolens L. and Melaleuca alternifolia Cheel., against planktonic and biofilm forms of five selected reference strains, namely Staphylococcus aureus, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. To obtain cohesive results, we applied four various methodological approaches: to assess the activity of the liquid fraction of EOs, disc diffusion and the microdilution method were applied; to test EOs’ volatile fraction, the AntiBioVol assay and modified Antibiofilm Dressing Activity Measurement (A.D.A.M.) were used. The molecular composition and dynamics of antimicrobial substances released from specific EOs was measured using Gas Chromatography–Mass Spectrometry (GC-MS). The antimicrobial potency of EO’s volatile fraction against biofilm formed by tested strains differed from that of the liquid fraction and was related to the molecular weight of volatile compounds. The liquid fraction of CW-EO and volatile fraction of F-EO acted in the strongest manner against biofilm of C. albicans. The addition of 0.5% Tween 20 to liquid phase, enhanced activity of G-EO against E. coli and K. pneumoniae biofilm. EO activity depended on the microbial species it was applied against and the chosen assessment methodology. While all tested EOs have shown a certain level of antimicrobial and antibiofilm effect, our results indicate that the choice of EO to be applied against a specific biofilm-forming pathogen requires careful consideration with regard to the above-listed aspects. Nevertheless, the results presented in this research contribute to the growing body of evidence indicating the beneficial effects of EOs, which may be applied to fight biofilm-forming pathogens.

Antifungal Properties of Essential Oils and Their Compounds for Application in Skin Fungal Infections: Conventional and Nonconventional Approaches

Essential oils (EOs) are known to have varying degrees of antimicrobial properties that are mainly due to the presence of bioactive compounds. These include antiviral, nematicidal, antifungal, insecticidal and antioxidant properties. This review highlights the potential of EOs and their compounds for application as antifungal agents for the treatment of skin diseases via conventional and nonconventional approaches. A search was conducted using three databases (Scopus, Web of Science, Google Scholar), and all relevant articles from the period of 2010-2020 that are freely available in English were extracted. In our findings, EOs with a high percentage of monoterpenes showed strong ability as potential antifungal agents. Lavandula sp., Salvia sp., Thymus sp., Citrus sp., and Cymbopogon sp. were among the various species found to show excellent antifungal properties against various skin diseases. Some researchers developed advanced formulations such as gel, semi-solid, and ointment bases to further evaluate the effectiveness of EOs as antifungal agents. To date, most studies on the application of EOs as antifungal agents were performed using in vitro techniques, and only a limited number pursued in vivo and intervention-based research.

Antioxidant, Antimicrobial and Antiviral Properties of Herbal Materials

Recently, increasing public concern about hygiene has been driving many studies to investigate antimicrobial and antiviral agents. However, the use of any antimicrobial agents must be limited due to their possible toxic or harmful effects. In recent years, due to previous antibiotics' lesser side effects, the use of herbal materials instead of synthetic or chemical drugs is increasing. Herbal materials are found in medicines. Herbs can be used in the form of plant extracts or as their active components. Furthermore, most of the world's populations used herbal materials due to their strong antimicrobial properties and primary healthcare benefits. For example, herbs are an excellent material to replace nanosilver as an antibiotic and antiviral agent. The use of nanosilver involves an ROS-mediated mechanism that might lead to oxidative stress-related cancer, cytotoxicity, and heart diseases. Oxidative stress further leads to increased ROS production and also delays the cellular processes involved in wound healing. Therefore, existing antibiotic drugs can be replaced with biomaterials such as herbal medicine with high antimicrobial, antiviral, and antioxidant activity. This review paper highlights the antibacterial, antiviral, and radical scavenger (antioxidant) properties of herbal materials. Antimicrobial activity, radical scavenger ability, the potential for antimicrobial, antiviral, and anticancer agents, and efficacy in eliminating bacteria and viruses and scavenging free radicals in herbal materials are discussed in this review. The presented herbal antimicrobial agents in this review include clove, portulaca, tribulus, eryngium, cinnamon, turmeric, ginger, thyme, pennyroyal, mint, fennel, chamomile, burdock, eucalyptus, primrose, lemon balm, mallow, and garlic, which are all summarized.

Sodium New Houttuyfonate Inhibits Candida albicans Biofilm Formation by Inhibiting the Ras1-cAMP-Efg1 Pathway Revealed by RNA-seq

Here, we aim to investigate the antifungal effect and mechanism of action of sodium new houttuyfonate (SNH) against Candida albicans. Microdilution analysis results showed that SNH possesses potent inhibitory activity against C. albicans SC5314, with a MIC₈₀ of 256 μg/mL. Furthermore, we found that SNH can effectively inhibit the initial adhesion of C. albicans. Inverted microscopy, crystal violet staining, scanning electron microscopy and confocal laser scanning microscopy results showed that morphological changes during the transition from yeast to hypha and the biofilm formation of C. albicans are repressed by SNH treatment. We also found that SNH can effectively inhibit the biofilm formation of clinical C. albicans strains (Z103, Z3044, Z1402, and Z1407) and SNH in combination with fluconazole, berberine chloride, caspofungin and itraconazole antifungal agents can synergistically inhibit the biofilm formation of C. albicans. Eukaryotic transcriptome sequencing and qRT-PCR results showed that SNH treatment resulted in significantly down-regulated expression in several biofilm formation related genes in the Ras1-cAMP-Efg1 pathway (ALS1, ALA1, ALS3, EAP1, RAS1, EFG1, HWP1, and TEC1) and significantly up-regulated expression in yeast form-associated genes (YWP1 and RHD1). We also found that SNH can effectively reduce the production of key messenger cAMP in the Ras1-cAMP-Efg1 pathway. Furthermore, using Galleria mellonella as an in vivo model we found that SNH can effectively treat C. albicans infection in vivo. Our presented results suggest that SNH exhibits potential antibiofilm effects related to inhibiting the Ras1-cAMP-Efg1 pathway in the biofilm formation of C. albicans.

Antioxidant, Anti-Inflammatory, and Microbial-Modulating Activities of Essential Oils: Implications in Colonic Pathophysiology

Essential oils (EOs) are a complex mixture of hydrophobic and volatile compounds synthesized from aromatic plants, most of them commonly used in the human diet. In recent years, many studies have analyzed their antimicrobial, antioxidant, anti-inflammatory, immunomodulatory and anticancer properties in vitro and on experimentally induced animal models of colitis and colorectal cancer. However, there are still few clinical studies aimed to understand their role in the modulation of the intestinal pathophysiology. Many EOs and some of their molecules have demonstrated their efficacy in inhibiting bacterial, fungi and virus replication and in modulating the inflammatory and oxidative processes that take place in experimental colitis. In addition to this, their antitumor activity against colorectal cancer models makes them extremely interesting compounds for the modulation of the pathophysiology of the large bowel. The characterization of these EOs is made difficult by their complexity and by the different compositions present in the same oil having different geographical origins. This review tries to shift the focus from the EOs to their individual compounds, to expand their possible applications in modulating colon pathophysiology.

Citrus lemon essential oil nanoemulsion (CLEO-NE), a safe cell-depended apoptosis inducer in human A549 lung cancer cells with anti-angiogenic activity

Aims: Citrus lemon essential oil (CLEO) has been introduced as a strong antioxidant mixture. However, it is not efficient enough due to its hydrophobic nature. Nanoemulsions improve the drugs' bio-compatibility in aqueous conditions.Methods: The CLEO nanoemulsion (CLEO-NE) was formulated by ultrasound-based-emulsification and they were characterised. The anti-angiogenic and antioxidant activities were studied by the chicken chorioallantoic membrane (CAM) and antioxidant (ABTS and DPPH) assays, respectively. Finally, the apoptotic property of CLEO-NE on both HFF and A549 was evaluated by [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assay and real time-PCR (measuring Cas-3 gene expression).Results: The 30.2-nm CLEO-NE droplets significantly increased Cas-3 in A549 cells and decreased angiogenesis in chick embryo chorioallantoic membrane (p < 0.01).Conclusion: In conclusion, CLEO-NE has the potential to be used as a safe cell-depended anticancer agent for human lung cancer. However, further genes and cell lines have to be studied to clarify its targeted-anticancer activity.

Chemical compositions, radical scavenging capacities and antimicrobial activities in seeds of Satureja hortensis L. and Mentha spicata L. subsp. spicata from Turkey

The present study determined some biological compounds, radical scavenging activity and antimicrobial capacity in seeds of Satureja hortensis L. and Mentha spicata L. subsp. spicata. Alpha-linolenic acid (C18:3 n3) has been found to be the major polyunsaturated fatty acid of Satureja hortensis L. (66.24 ± 1.24%) and Mentha spicata L. subsp. spicata (48.17 ± 1.01%). Linoleic acid (C18:2 n6) is identified as the second major polyunsaturated fatty acid in the present study and oleic acid (C18:1 n9) is determined as the major monounsaturated fatty acid. Current study showed that Satureja hortensis L. and Mentha spicata L. subsp. spicata have low levels of saturated fatty acids. It has been demonstrated that ergosterol (263.1 ± 2.14 µg/g), stigmasterol (39.07 ± 0.91 µg/g) and beta-sitosterol (14.64 ± 0.49 µg/g) have been found in Mentha spicata L. subsp. spicata, while ergosterol (69.41 ± 1.75 µg/g) and beta-sitosterol (19.81 ± 1.14 µg/g) have been determined in Satureja hortensis L. Also, this study determined that Satureja hortensis L. and Mentha spicata L. subsp. spicata have low lipide-soluble vitamin content. Furthermore, it has been found that Satureja hortensis L. contains naringenin (612.57 ± 2.57 µg/g), morin (86.97 ± 1.12 µg/g), quercetin (22.87 ± 0.75 µg/g), and kaempferol (20.11 ± 0.94 µg/g) while naringenin (135.91 ± 1.91 µg/g), naringin (61.23 ± 2.15 µg/g) and quercetin (47.51 ± 1.17 µg/g) have been detected as major flavonoids in the seeds of Mentha spicata L. subsp. spicata. The results of the present study suggest that methanol extracts of Satureja hortensis L. and Mentha spicata L. subsp. spicata have significant free radical scavenging activity. The present results revealed that Satureja hortensis L. and Mentha spicata L. subsp. spicata showed major activity against gram-positive and gram-negative microorganisms, fungi and yeast.

Antioxidant Property and Bactericidal Activity of Linum usitatissimum Seed Essential Oil Nanoemulsion (LSEO-NE) on Staphylococcus aureus

Background: Linum usitatissimum Seed Essential Oil (LSEO) as an efficient antimicrobial compound contains various types of phytochemicals, such as lignans and phenols. Objectives: In the current study, we produced LSEO nanoemulsion (LSEO-NE) to study its antioxidant capacity and bactericidal activity against Staphylococcus aureus. Methods: The LSEO-NE was produced using the ultrasonication method and characterized by Atomic Force Microscopy (AFM), Dynamic Light Scattering (DLS), and Scanning Electron Microscopy (SEM). Then, we measured its antioxidant activity utilizing both ABTS and DPPH tests at four different LSEO-NE concentrations (200, 600, 800, and 1000 µg/mL) compared to glutathione. Finally, we evaluated its bactericidal activity on S. aureus by studying Antibiotic Susceptibility Testing (AST) using LSEO-NE-smeared discs compared to non-smeared and kanamycin discs. Results: The 67.3 nm droplets of LSEO-NE with PDI of 0.452 exhibited strong antioxidant activity, similar to glutathione, in both ABTS (IC50 = 350 µg/mL) and DPPH (IC50 = 235 µg/mL) tests. Moreover, the AST results revealed the significant sensitivity of S. aureus to LSEO-NE-smeared discs when compared to non-smeared and kanamycin discs. Conclusions: According to the results, LSEO-NE can be applied as a safe, natural, and effective antibiotic for bacterial infections caused by S. aureus in most organs, such as the respiratory system and skin. However, further in vivo studies are required to evaluate the LSEO-NE antibacterial efficiency against other pathogenic S. aureus strains.

Wound Healing Activity of the Essential Oil of Bursera morelensis, in Mice

Bursera morelensis is used in Mexican folk medicine to treat wounds on the skin. It is an endemic tree known as “aceitillo”, and the antibacterial and antifungal activity of its essential oil has been verified; it also acts as an anti-inflammatory. All of these reported biological activities make the essential oil of B. morelensis a candidate to accelerate the wound-healing process. The objective was to determine the wound-healing properties of B. morelensis’ essential oil on a murine model. The essential oil was obtained by hydro-distillation, and the chemical analysis was performed by gas chromatography-mass spectrometry (GC-MS). In the murine model, wound-healing efficacy (WHE) and wound contraction (WC) were evaluated. Cytotoxic activity was evaluated in vitro using peritoneal macrophages from BALB/c mice. The results showed that 18 terpenoid-type compounds were identified in the essential oil. The essential oil had remarkable WHE regardless of the dose and accelerated WC and was not cytotoxic. In vitro tests with fibroblasts showed that cell viability was dose-dependent; by adding 1 mg/mL of essential oil (EO) to the culture medium, cell viability decreased below 80%, while, at doses of 0.1 and 0.01 mg/mL, it remained around 90%; thus, EO did not intervene in fibroblast proliferation, but it did influence fibroblast migration when wound-like was done in monolayer cultures. The results of this study demonstrated that the essential oil was a pro-wound-healing agent because it had good healing effectiveness with scars with good tensile strength and accelerated repair. The probable mechanism of action of the EO of B. morelensis, during the healing process, is the promotion of the migration of fibroblasts to the site of the wound, making them active in the production of collagen and promoting the remodeling of this collagen.

Biofunctionalization of Natural Fiber-Reinforced Biocomposites for Biomedical Applications

In the last ten years, environmental consciousness has increased worldwide, leading to the development of eco-friendly materials to replace synthetic ones. Natural fibers are extracted from renewable resources at low cost. Their combination with synthetic polymers as reinforcement materials has been an important step forward in that direction. The sustainability and excellent physical and biological (e.g., biocompatibility, antimicrobial activity) properties of these biocomposites have extended their application to the biomedical field. This paper offers a detailed overview of the extraction and separation processes applied to natural fibers and their posterior chemical and physical modifications for biocomposite fabrication. Because of the requirements for biomedical device production, specialized biomolecules are currently being incorporated onto these biocomposites. From antibiotics to peptides and plant extracts, to name a few, this review explores their impact on the final biocomposite product, in light of their individual or combined effect, and analyzes the most recurrent strategies for biomolecule immobilization.

Essential Oils and Their Natural Active Compounds Presenting Antifungal Properties

The current rise in invasive fungal infections due to the increase in immunosuppressive therapies is a real concern. Moreover, the emergence of resistant strains induces therapeutic failures. In light of these issues, new classes of antifungals are anticipated. Therefore, the plant kingdom represents an immense potential of natural resources to exploit for these purposes. The aim of this review is to provide information about the antifungal effect of some important essential oils, and to describe the advances made in determining the mechanism of action more precisely. Finally, the issues of toxicity and resistance of fungi to essential oils will be discussed.

Antifungal activity of essential oil from Mentha spicata L. and Mentha pulegium L. growing wild in Sardinia island (Italy)

This study aims to evaluate the antifungal activity of Mentha spicata L. and Mentha pulegium L. from Sardinia and to assess their efficacy on virulence factors for Candida albicans, particularly on the inhibition of the germ tube formation. The major compounds of the essential oils were carvone (62.9%) for M. spicata and pulegone (86.2%) for M. pulegium. The essential oil from M. spicata showed a more preeminent effect against Cryptococcus neoformans and the dermatophytes Trichophyton rubrum and T. verrucosum (0.32 μL/mL). Both oils were very effective in inhibiting C. albicans germ tube formation, at doses well below their MIC (0.16 μL/mL).

Essential Oils as Antimicrobial Agents-Myth or Real Alternative?

Herbs and the essential oils derived from them have been used from the beginning of human history for different purposes. Their beneficial properties have been applied to mask unpleasant odors, attract the attention of other people, add flavor and aroma properties to prepared dishes, perfumes, and cosmetics, etc. Herbs and essential oils (EOs) have also been used in medicine because of their biological properties, such as larvicidal action, analgesic and anti-inflammatory properties, antioxidant, fungicide, and antitumor activities, and many more. Many EOs exhibit antimicrobial properties, which is extremely important in fields of science and industry, such as medicine, agriculture, or cosmetology. Among the 250 EOs which are commercially available, about a dozen possess high antimicrobial potential. According to available papers and patents, EOs seem to be a potential alternative to synthetic compounds, especially because of the resistance that has been increasingly developed by pathogenic microorganisms. In this review we summarize the latest research studies about the most-active EOs that are known and used because of their antimicrobial properties. Finally, it is noteworthy that the antimicrobial activities of EOs are not preeminent for all strains. Further investigations should, thus, focus on targeting EOs and microorganisms.

The harmful effects of acute PM2.5 exposure to the heart and a novel preventive and therapeutic function of CEOs

Epidemiological researches have demonstrated the relationship between PM2.5 exposure and increased morbidity and mortality of cardiovascular injury. However, no effective therapeutic method was established. The purpose of this study is to investigate the effect of acute PM2.5 exposure on the mice heart tissue and explore the therapeutic effects of compound essential oils (CEOs) in this model. In this study, after mice were exposed to PM2.5 intratracheally, some obvious histopathological changes as well as some great alterations of proinflammatory cytokines were observed in the heart tissue. The imbalance of oxidative stress, the altered Ca2+ channel related proteins and the increased intracellular free Ca2+ were all involved in the heart impairment and would also be investigated in this model. The CEOs alleviated the heart impairment via its antioxidant effect rather than its anti-inflammatory function because our results revealed that oxidative stress related indicators were restored after CEOs administration. At the same time, increased concentration of intracellular free Ca2+ and ROS induced by PM2.5 were reduced after NAC (N-Acetyl-L-cysteine) administration. These data suggested that the acute PM2.5 exposure would damage heart tissue by inducing the inflammatory response, oxidative stress and intracellular free Ca2+ overload. PM2.5-induced oxidative stress probably increase intracellular free Ca2+ via RYR2 and SERCA2a. CEOs have the potential to be a novel effective and convenient therapeutic method to prevent and treat the acute heart impairment induced by PM2.5 via its antioxidant function.