Essential Oils: Chemistry and Pharmacological Activities

Antifungal activity of Caryocar brasiliense camb. Alone or along with antifungal agents against multidrug-resistant Candida auris

ETHNOPHARMACOLOGICAL RELEVANCE

Candida auris poses a severe global health threat, with many strains resistant to antifungal treatments, complicating therapy. Exploring natural compounds alongside conventional drugs offers promising therapeutic avenues. The antifungal potential of the ethanolic extract from Caryocar brasiliense (Cb-EE), a plant native to the Brazilian cerrado and renowned for its medicinal properties, was investigated against C. auris.

AIM OF THE STUDY

The study examined the chemical composition, antifungal activity, mechanisms of action, and in vivo effects of Cb-EE.

MATERIALS AND METHODS

Leaves of C. brasiliense were processed to extract ethanolic extract, which was evaluated for phenolic compounds, flavonoids, and tannins. The antifungal capacity was determined through broth microdilution and checkerboard methods, assessing interaction with conventional antifungals.

RESULTS

Cb-EE demonstrated fungistatic activity against various Candida species and Cryptococcus neoformans. Synergy with fluconazole and additive effects with other drugs were observed. Cb-EE inhibited C. auris growth, with the combination of fluconazole extending inhibition. Mechanistic studies revealed interference with fungal membranes, confirmed by sorbitol protection assays, cellular permeability tests, and scanning electron microscopy (SEM). Hemocompatibility and in vivo toxicity tests on Tenebrio molitor showed safety.

CONCLUSION

Cb-EE, alone or in combination with fluconazole, effectively treated C. auris infections in vitro and in vivo, suggesting its prospective role as an antifungal agent against this emerging pathogen.

Growth performance, antioxidant status, intestinal morphology, and body composition of Nile tilapia (Oreochromis niloticus) supplemented with essential oils: A meta-analysis

This study aimed to evaluate the effects of dietary supplementation with essential oils (EOS) on growth performance, antioxidant status in blood serum, intestinal morphology, and whole-body composition of Nile tilapia (Oreochromis niloticus) through a meta-analytic approach. The search and collection of scientific articles were conducted using the PRISMA methodology, and 45 full-text scientific articles were obtained. The data used in the meta-analysis were extracted from these 45 documents. The effect size was assessed through weighted mean differences (WMD) using Der-Simonian and Laird random effects models. Dietary supplementation with EOS increased (P < 0.001) final weight, body weight gain, specific growth rate, feed intake, protein efficiency ratio, and survival but decreased (P < 0.001) feed conversion ratio. In blood serum, EOS supplementation decreased (P < 0.001) the concentration of malondialdehyde and increased (P < 0.001) the concentration of catalase, superoxide dismutase, and glutathione peroxidase. In the foregut, midgut, and hindgut, greater (P < 0.01) villus height, villus width, and number of goblet cells were observed in response to EOS supplementation. EOS supplementation increased (P < 0.01) crude protein content and decreased (P < 0.05) crude lipid content in the whole-body. In conclusion, essential oils can be used as a dietary additive to improve growth performance, antioxidant status in blood serum, and intestinal morphology in Nile tilapia. Likewise, supplementation with essential oils increases the protein content and decreases the fat content in the whole-body of Nile tilapia.

Chemical Composition and Antibacterial, Antioxidant, and Cytotoxic Activities of Essential Oils from Leaves and Stems of Aeschynomene indica L

The objective of this study was to analyze the chemical composition and evaluate the biological capabilities of the essential oils (EOs) extracted from leaves and stems of wild Aeschynomene indica L. plants by the hydrodistillation method. By using GC-FID/MS, fifty-six and fifty-five compounds, representing 95.1 and 97.6% of the essential oils in the leaves and stems, respectively, were characterized. The predominant constituents of A. indica EOs were (E)-caryophyllene, linalool, viridiflorol, phytol, hexadecanoic acid, trans-verbenol, and α-guaiene. The antibacterial and synergistic activities of the EOs were assessed by microdilution and checkerboard assays. The results revealed a potent inhibition and bactericidal activity against Staphylococcus aureus and Bacillus subtilis with MICs of 0.312-0.625 mg/mL. When combined with traditional antibiotics, the essential oils of A. indica possessed excellent synergistic effects against all tested bacteria. Additionally, the EOs of A. indica leaves showed higher antioxidant activity (IC50 = 0.11 ± 0.01 µg/mL) compared to the stem oil (IC50 = 0.19 ± 0.01 µg/mL) using the ABTS radical scavenging assay. The in vitro cytotoxicity of EOs against human cancer cell lines HepG2, MCF-7, A-549, and HCT-116 was examined, and MTT assays showed that the EOs possessed a significant cytotoxic potential against MCF-7 breast cancer cells, with IC50 values of 10.04 ± 1.82 and 15.89 ± 1.66 μg/mL, and a moderate cytotoxic activity against other tested cells. In conclusion, the A. indica EOs could be considered a potential source of pharmacologically active compounds.

A green and efficient approach for the simultaneous extraction and mechanisms of essential oil and lignin from Cinnamomum camphora: Process optimization based on deep learning

The utilization and economic benefits of biomass resources can be maximized through rational design and process optimization. In this study, an innovative approach for the simultaneous extraction of essential oil and lignin from Cinnamomum camphora leaves by deep eutectic solvent (DES) and optimization of the process parameters was achieved using deep learning tools. With the water content of 40 %, liquid-solid ratio of 9.00 mL/g, and distillation time of 51.81 min, the yields of the essential oil and lignin reached 3.15 ± 0.02 % and 9.75 ± 0.15 %, respectively. Notably, the efficiency of simultaneous extraction of essential oil improved by 23 % compared to that of traditional steam distillation. Moreover, the extraction mechanism of the process was clarified. The connection between lignin with cellulose and hemicellulose was disintegrated by the DES, resulting in lignin shedding and hence accelerating the dissolution of essential oil. Moreover, the compositions of lignin and essential oil were also identified.

From Herd Health to Public Health: Digital Tools for Combating Antibiotic Resistance in Dairy Farms

The emergence of antimicrobial resistance (AMR) is a significant threat to global food security, human health, and the future of livestock production. Higher rates of antimicrobial use in dairy farming and the sheer lack of new antimicrobials available for use focused attention on the question of how the dairy production sector contributed to the development of AMR and paved the path toward taking action to curtail it on the targeted type of farms. This paper aims to provide an introduction to a phenomenon that has gained considerable attention in the recent past due to its ever-increasing impact, the use of antimicrobial drugs, the emergence of antimicrobial resistance (AMR) on dairy farms, and seeks to discuss the possibilities of approaches such as digital health monitoring and precision livestock farming. Using sensors, data, knowledge, automation, etc., digital health monitoring, as well as Precision Livestock Farming (PLF), is expected to enhance health control and minimize disease and antimicrobial usage. The work presents a literature review on the current status and trends of AMR in dairy farms, an understanding of the concept of digital health monitoring and PLF, and the presentation and usefulness of digital health monitoring and PLF in preventing AMR. The study also analyses the strengths and weaknesses of adopting and incorporating digital technologies and artificial intelligence for dairy farming and presents areas for further study and level of use.

Hydrazinated geraniol derivatives as potential broad-spectrum antiprotozoal agents

Geraniol, a primary component of several essential oils, has been associated with broad-spectrum antiprotozoal activities, although moderate to weak. This study primarily concentrated on the synthesis of hydrazinated geraniol derivatives as potential antiprotozoal agents. The synthesised compounds were tested in vitro against different parasitic protozoans of clinical relevance, including Trypanosoma brucei brucei, Trypanosoma brucei rhodesiense, Trypanosoma cruzi and Leishmania infantum. Compounds 6, 8, 13, 14 and 15 demonstrated low micromolar activity against the different parasites. Compounds 8, 13, 14 and 15 had the highest efficacy against Trypanosoma brucei rhodesiense, as indicated by their respective IC50 values of 0.74, 0.56, 1.26 and 1.00 µM. Compounds 6, 14 and 15 displayed the best activity against Trypanosoma brucei brucei, with IC50 values of 1.49, 1.48 and 1.85 µM, respectively. The activity of compounds 6, 14 and 15 also extended to intracellular Trypanosoma cruzi, with IC50 values of 5.14, 6.30 and 4.90 µM, respectively. Compound 6, with an IC50 value of 11.73 µM, and compound 14, with an IC50 value of 8.14 µM, demonstrated some modest antileishmanial activity.

Essential Oils from Southern Italian Aromatic Plants Synergize with Antibiotics against Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecalis Cell Growth and Biofilm Formation

The spread of antibiotic-resistant pathogens has prompted the development of novel approaches to identify molecules that synergize with antibiotics to enhance their efficacy. This study aimed to investigate the effects of ten Essential Oils (EOs) on the activity of nine antibiotics in influencing growth and biofilm formation in Escherichia coli, Pseudomonas aeruginosa, and Enterococcus faecalis. The effects of the EOs alone and in combination with antibiotics on both bacterial growth and biofilm formation were analyzed by measuring the MIC values through the broth microdilution method and the crystal violet assay, respectively. All EOs inhibited the growth of E. coli (1.25 ≤ MIC ≤ 5 mg/mL) while the growth of P. aeruginosa and E. faecalis was only affected by EOs from Origanum vulgare, (MIC = 5 mg/mL) and O. vulgare (MIC = 1.25 mg/mL) and Salvia rosmarinus (MIC = 5 mg/mL), respectively. In E. coli, most EOs induced a four- to sixteen-fold reduction in the MIC values of ampicillin, ciprofloxacin, ceftriaxone, gentamicin, and streptomycin, while in E. faecalis such a reduction is observed in combinations of ciprofloxacin with C. nepeta, C. bergamia, C. limon, C. reticulata, and F. vulgare, of gentamicin with O. vulgare, and of tetracycline with C. limon and O. vulgare. A smaller effect was observed in P. aeruginosa, in which only C. bergamia reduced the concentration of tetracycline four-fold. EO-antibiotic combinations also inhibit the biofilm formation. More precisely, all EOs with ciprofloxacin in E. coli, tetracycline in P. aeruginosa, and gentamicin in E. faecalis showed the highest percentage of inhibition. Combinations induce up- and down-methylation of cytosines and adenines compared to EO or antibiotics alone. The study provides evidence about the role of EOs in enhancing the action of antibiotics by influencing key processes involved in resistance mechanisms such as biofilm formation and epigenetic changes. Synergistic interactions should be effectively considered in dealing with pathogenic microorganisms.

Sequential Separation of Essential Oil Components during Hydrodistillation of Fresh Foliage from Azorean Cryptomeria japonica (Cupressaceae): Effects on Antibacterial, Antifungal, and Free Radical Scavenging Activities

Cryptomeria japonica wood industry generates large amounts of foliage biomass residues. Due to the increasing applications and markets for essential oils (EOs), fresh Azorean C. japonica foliage (Az-CJF) residues are used for local EO production. Hydrodistillation (HD), a common process for obtaining EOs, also provides the possibility to fractionate them. Thus, this study evaluated the in vitro antimicrobial and antioxidant activities of six Az-CJF EO fractions (Frs. 1-6), collected at sequential HD timeframes (HDTs: 0-2, 2-10, 10-30, 30-60, 60-120, and 120-240 min), in comparison to the crude EO, obtained from a non-fractionated HD (0-240 min HDT). Antimicrobial activities were assessed via disc diffusion method against seven bacteria (foodborne and/or human pathogens) and two Penicillium spp. (phytopathogenic fungi), and antioxidant activity was estimated using DPPH and ABTS assays. Concerning the antibacterial activity, all the EO samples were effective only toward Gram-positive bacteria. Fractions 1-3 (<30 min HDT) were the most active, with growth inhibition zones (GIZ) of 7.0-23.3 mm (1.4-2.2 times higher than those of the crude EO), being Bacillus spp. (B. licheniformis and B. subtilis) the most sensitive, followed by Staphylococcus aureus and Micrococcus luteus. Regarding the antifungal activity, Frs. 1-3 also displayed the best activities, but only against P. italicum (GIZ around 9.0 mm), while the crude EO showed no antifungal activity. Overall, the best antimicrobial properties of Frs. 1-3 could be attributed, at least in part, to their highest content in α-pinene and bornyl acetate. On the other hand, Frs. 4-6 (>30 min HDT) exhibited the strongest antioxidant activities (EC50 values: 1.5-2.3 and 1.0-1.7 mg mL-1 for DPPH and ABTS, respectively), being at least 1.3-fold higher than those of the crude EO. The presence of nezukol, elemol, and eudesmol isomers could strongly contribute to the best free radical scavenging properties of Frs. 4-6. In conclusion, HD was found to be an efficient process for obtaining new Az-CJF EO fractions with variable and enhanced bioactivities due to their differential composition, as assessed using GC-MS. Hence, these findings could contribute to increasing the commercial potential of the C. japonica EO industry, namely, the Fr2 and Fr6, which presented the most significant activities and can have potential applications in the food, medical, and agriculture sectors.

Artemisia fragrans Willd. Essential Oil: Chemical Profile and Insecticidal Potential against the Confused Flour Beetle, Tribolium confusum du Val

The confused flour beetle, Tribolium confusum du Val, is one of the cosmopolitan and polyphagous storage insect pests. The frequent application of chemical insecticides has resulted in several side effects, including threats to human health and non-target organisms and the resistance of insect pests. In the current study, the fumigant toxicity and feeding deterrence potential of Artemisia fragrans Willd. essential oil on T. confusum adults were investigated. The essential oil was rich in terpenic compounds, in which α-thujone (27.8%) and 1,8-cineole (22.8%) were dominant. The essential oil displayed significant fumigant toxicity on T. confusum, where a concentration of 35.3 μL/L caused 100% mortality of the treated adults after 48 h. The LC30 and LC40 values (lethal concentrations to kill 30% and 40% of tested insects: 15.1 and 18.4 μL/L, respectively) significantly decreased the nutritional indices of the pest, including the consumption index, relative consumption rate, and relative growth rate. The feeding deterrence index of the essential oil were calculated as being 62.29 and 48.66% for the concentrations of 15.1 and 18.4 μL/L after 5 days, respectively. Accordingly, A. fragrans essential oil can be considered an efficient, available, and natural alternative to detrimental chemical pesticides in the management of T. confusum.

Essential Oil from Vietnamese Peperomia leptostachya Hook. & Arn. (Piperaceae): Chemical Composition, Antioxidant, Anti-Inflammatory, Cytotoxic Activities, and In Silico Analysis

This study is the first to investigate the chemical composition and antioxidant, anti-inflammatory, and cytotoxic activities of Peperomia leptostachya leaf oil. A yellow oil was obtained through hydro-distillation, with a yield of 0.1% (w/w). The GC-MS analysis revealed 66 compounds, constituting 99.6% of the oil. Sesquiterpene hydrocarbons predominated (70.4%), followed by monoterpene hydrocarbons (13.2%), oxygenated sesquiterpenes (12.4%), non-terpenic compounds (2.0%), and oxygenated monoterpenes (1.6%). Major constituents included germacrene D (25.1%), (E)-caryophyllene (17.4%), bicyclogermacrene (6.6%), α-pinene (6.2%), and β-pinene (4.7%). The assessment of antioxidant capacity via 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay yielded a weak effect, with an IC50 value > 100 µg/mL. The inhibition of lipopolysaccharide-induced nitric oxide production in RAW 264.7 cells was quantified using the MTT assay, showing an IC50 value of 15.15 ± 0.68 µg/mL. Furthermore, cytotoxic effects on SK-LU-1 cell line growth were evaluated using the sulforhodamine B assay, resulting in an IC50 value of 37.45 ± 2.43 μg/mL. The anti-inflammatory activity was notable among the analyzed bioactivities of this oil. By employing a computational model, the predominant secondary metabolites in the essential oil were selected as candidates for interaction analysis with cyclooxygenase-2, an enzyme implicated in the inflammatory response. Our findings suggest that P. leptostachya leaf oil could serve as a potential source of natural compounds with prospective therapeutic effects in treating inflammatory conditions.

Formulation of essential oils-loaded solid lipid nanoparticles-based chitosan/PVA hydrogels to control the growth of Botrytis cinerea and Penicillium expansum

Botrytis cinerea and Penicillium expansum are phytopathogenic fungi that produce the deterioration of fruits. Thus, essential oil (EO) has emerged as a sustainable strategy to minimize the use of synthetic fungicides, but their volatility and scarce solubility restrict their application. This study proposes the EO of Oreganum vulgare and Thymus vulgaris-loaded solid lipid nanoparticles (SLN) based chitosan/PVA hydrogels to reduce the infestation of fungi phytopathogen. EO of O. vulgare and T. vulgaris-loaded SLN had a good homogeneity (0.21-0.35) and stability (-28.8 to -33.0 mV) with a mean size of 180.4-188.4 nm. The optimization of EO-loaded SLN showed that the encapsulation of 800 and 1200 μL L-1 of EO of O vulgare and T. vulgaris had the best particle size. EO-loaded SLN significantly reduced the mycelial growth and spore germination of both fungi pathogen. EO-loaded SLN into hydrogels showed appropriate physicochemical characteristics to apply under environmental conditions. Furthermore, rheological analyses evidenced that hydrogels had solid-like characteristics and elastic behavior. EO-loaded SLN-based hydrogels inhibited the spore germination in B. cinerea (80.9 %) and P. expansum (55.7 %). These results show that SLN and hydrogels are eco-friendly strategies for applying EO with antifungal activity.

Efficacy of Salvia officinalis Shrub as a Sustainable Feed Additive for Reducing Ruminal Methane Production and Enhancing Fermentation in Ruminants

The objective of this study was to evaluate the effects of the inclusion of dried Salvia officinalis (SO) shrub leaves on nutrient degradability, ruminal in vitro fermentation, gas production (GP), methane (CH4), and carbon dioxide (CO2) productions. Dried and ground SO shrub leaves were included at 0% (control), 0.5%, 1%, 1.5%, and 2% DM of a diet consisting of (per kg DM) 500 g concentrate feed mixture, 400 g berseem hay, and 100 g rice straw. The diet was incubated for 48 h. The asymptotic GP and the rate of GP changed linearly and quadratically (p < 0.01), with the highest GP observed at 1% inclusion of SO and then decreasing thereafter with greater inclusion (i.e., 1.5% and 2%), while CH4 production and its rate decreased linearly (p < 0.01) with all levels of SO inclusion. A linear increase in CO2 production and its rate was also found with an increasing level of SO inclusion in the diet (p < 0.05). Furthermore, the degradability of DM, NDF, and the concentration of total short-chain fatty acids and acetate changed linearly and quadratically, with the greatest being found at 1% SO inclusion and then steadily declining after (p < 0.01) with the 1.5% and 2% inclusion levels. Meanwhile, the propionate, NH3-N, and microbial crude protein levels showed similar trends, with the plateau found at 1% inclusion of SO, where there was no change in butyrate concentration. Moreover, the pH, metabolizable energy, and partitioning factor (PF24) also changed linearly and quadratically (p < 0.05), where the pH and PF24 were considerably reduced and ME increased with a 1% inclusion of SO (p < 0.05). In summary, SO at 1% inclusion in the diet showed the potential to improve gas production kinetics, nutrient degradability, and the ruminal fermentation profile, with a more significant reduction in ruminal CH4 production suggesting that SO at 1% could be included in the ruminant diet to reduce their carbon footprint and increase the production performance.

Combination of Chromatographic Analysis and Chemometric Methods with Bioactivity Evaluation of the Antibacterial Properties of Helichrysum italicum Essential Oil

Helichrysum italicum (immortelle) essential oil is one of the most popular essential oils worldwide and it has many beneficial properties, including antimicrobial. However, in this plant, the chemical diversity of the essential oil is very pronounced. The aim of this work was to process the GC-MS results of four samples of H. italicum essential oil of Serbian origin by chemometric tools, and evaluate the antimicrobial activity in vitro and in silico. Overall, 47 compounds were identified, the most abundant were γ-curcumene, α-pinene, and ar-curcumene, followed by α-ylangene, neryl acetate, trans-caryophyllene, italicene, α-selinene, limonene, and italidiones. Although the four samples of H. italicum essential oil used in this study were obtained from different producers in Serbia, they belong to the type of essential oil rich in sesquiterpenes (γ-curcumene and ar-curcumene chemotype). In vitro antimicrobial potential showed that five were sensitive among ten strains of tested microorganisms: Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Saccharomyces cerevisiae, and Candida albicans. Therefore, these microorganism models were used further for in silico molecular docking through the mechanism of ATP-ase inhibitory activity. Results showed that among all compounds from H. italicum essential oil, neryl acetate has the highest predicted binding energy. Artificial neural network modeling (ANN) showed that two major compounds γ-curcumene and α-pinene, as well as minor compounds such as trans-β-ocimene, terpinolene, terpinene-4-ol, isoitalicene, italicene, cis-α-bergamotene, trans-α-bergamotene, italidiones, trans-β-farnesene, γ-selinene, β-selinene, α-selinene, and guaiol are responsible for the antimicrobial activity of H. italicum essential oil. The results of this study indicate that H. italicum essential oil samples rich in γ-curcumene, α-pinene, and ar-curcumene cultivated in Serbia (Balkan) have antimicrobial potential both in vitro and in silico. In addition, according to ANN modeling, the proportion of neryl acetate and other compounds detected in these samples has the potential to exhibit antimicrobial activity.

Essential Oils: Chemistry and Pharmacological Activities-Part II

The importance of essential oils and their components in the industrial sector is attributed to their chemical characteristics and their application in the development of products in the areas of cosmetology, food, and pharmaceuticals. However, the pharmacological properties of this class of natural products have been extensively investigated and indicate their applicability for obtaining new drugs. Therefore, this review discusses the use of these oils as starting materials to synthesize more complex molecules and products with greater commercial value and clinic potential. Furthermore, the antiulcer, cardiovascular, and antidiabetic mechanisms of action are discussed. The main mechanistic aspects of the chemopreventive properties of oils against cancer are also presented. The data highlight essential oils and their derivatives as a strategic chemical group in the search for effective therapeutic agents against various diseases.

Bridging the Gap: Harnessing Plant Bioactive Molecules to Target Gut Microbiome Dysfunctions in Amyotrophic Lateral Sclerosis

The correlation between neurodegenerative diseases and the gut microbiome is increasingly evident, with amyotrophic lateral sclerosis (ALS) being particularly notable for its severity and lack of therapeutic options. The gut microbiota, implicated in the pathogenesis and development of ALS, plays a crucial role in the disease. Bioactive plant molecules, specifically volatile compounds in essential oils, offer a promising therapeutic avenue due to their anti-inflammatory properties and gut-modulating effects. Our narrative review aimed to identify microbiota-associated bacteria in ALS and analyze the benefits of administering bioactive plant molecules as much-needed therapeutic options in the management of this disease. A comprehensive search of PubMed database articles published before December 2023, encompassing research on cell, human, and animal ALS models, was conducted. After selecting, analyzing, and discussing key articles, bacteria linked to ALS pathogenesis and physiopathology were identified. Notably, positively highlighted bacteria included Akkermansia muciniphila (Verrucomicrobia phylum), Faecalibacterium prausnitzii, and Butyrivibrio spp. (Firmicutes phylum). Conversely, members of the Escherichia coli spp. (Proteobacteria phylum) and Ruminococcus spp. (Firmicutes phylum) stood out negatively in respect to ALS development. These bacteria were associated with molecular changes linked to ALS pathogenesis and evolution. Bioactive plant molecules can be directly associated with improvements in the microbiome, due to their role in reducing inflammation and oxidative stress, emerging as one of the most promising natural agents for enriching present-day ALS treatments.

Application of Cinnamomum burmannii Essential Oil in Promoting Wound Healing

Skin wounds, leading to infections and death, have a huge negative impact on healthcare systems around the world. Antibacterial therapy and the suppression of excessive inflammation help wounds heal. To date, the application of wound dressings, biologics and biomaterials (hydrogels, epidermal growth factor, stem cells, etc.) is limited due to their difficult and expensive preparation process. Cinnamomum burmannii (Nees & T. Nees) Blume is an herb in traditional medicine, and its essential oil is rich in D-borneol, with antibacterial and anti-inflammatory effects. However, it is not clear whether Cinnamomum burmannii essential oil has the function of promoting wound healing. This study analyzed 32 main components and their relative contents of essential oil using GC-MS. Then, network pharmacology was used to predict the possible targets of this essential oil in wound healing. We first proved this essential oil's effects in vitro and in vivo. Cinnamomum burmannii essential oil could not only promote the proliferation and migration of skin stromal cells, but also promote M2-type polarization of macrophages while inhibiting the expression of pro-inflammatory cytokines. This study explored the possible mechanism by which Cinnamomum burmannii essential oil promotes wound healing, providing a cheap and effective strategy for promoting wound healing.

The Therapeutic Potential of Essential Oils in Managing Inflammatory Skin Conditions: A Scoping Review

Conventional therapy is commonly used for the treatment of inflammatory skin conditions, but undesirable effects, such as erythema, dryness, skin thinning, and resistance to treatment, may cause poor patient compliance. Therefore, patients may seek complementary treatment with herbal plant products including essential oils (EOs). This scoping review aims to generate a broad overview of the EOs used to treat inflammatory skin conditions, namely, acne vulgaris, dermatitis and eczema, psoriasis, and rosacea, in a clinical setting. The quality, efficacy, and safety of various EOs, as well as the way in which they are prepared, are reviewed, and the potential, as well as the limitations, of EOs for the treatment of inflammatory skin conditions are discussed. Twenty-nine eligible studies (case studies, uncontrolled clinical studies, and randomized clinical studies) on the applications of EOs for inflammatory skin conditions were retrieved from scientific electronic databases (PubMed, Embase, Scopus, and the Cochrane Library). As an initial result, tea tree (Melaleuca alternifolia) oil emerged as the most studied EO. The clinical studies with tea tree oil gel for acne treatment showed an efficacy with fewer adverse reactions compared to conventional treatments. The uncontrolled studies indicated the potential efficacy of ajwain (Trachyspermum ammi) oil, eucalyptus (Eucalyptus globulus) oil, and cedarwood (Cedrus libani) oil in the treatment of acne, but further research is required to reach conclusive evidence. The placebo-controlled studies revealed the positive effects of kānuka (Kunzea ericoides) oil and frankincense (Boswellia spp.) oil in the treatment of psoriasis and eczema. The quality verification of the EO products was inconsistent, with some studies lacking analyses and transparency. The quality limitations of some studies included a small sample size, a short duration, and the absence of a control group. This present review underscores the need for extended, well-designed clinical studies to further assess the efficacy and safety of EOs for treating inflammatory skin conditions with products of assured quality and to further elucidate the mechanisms of action involved.

A Comparison between Bulgarian Tanacetum parthenium Essential Oil from Two Different Locations

Tanacetum parthenium L. (Asteraceae) is a perennial herbaceous plant with a long-standing historical use in traditional medicine. Recently Tanacetum parthenium L. essential oil has been associated with a promising potential for future applications in the pharmaceutical industry, in the cosmetics industry, and in agriculture. Investigations on the essential oil (EO) have indicated antimicrobial, antioxidant, and repellent activity. The present study aimed to evaluate the chemical composition of Bulgarian T. parthenium essential oil from two different regions, to compare the results to those reported previously in the literature, and to point out some of its future applications. The essential oils of the air-dried flowering aerial parts were obtained by hydrodistillation using a Clevenger-type apparatus. The chemical composition was evaluated using gas chromatography with mass spectrometry (GC-MS). It was established that the oxygenated monoterpenes were the predominant terpene class, followed by the monoterpene hydrocarbons. Significant qualitative and quantitative differences between both samples were revealed. Camphor (50.90%), camphene (16.12%), and bornyl acetate (6.05%) were the major constituents in the feverfew EO from the western Rhodope Mountains, while in the EO from the central Balkan mountains camphor (45.54%), trans-chrysanthenyl acetate (13.87%), and camphene (13.03%) were the most abundant components.

Redox profile of silver catfish challenged with Aeromonas hydrophila and treated with hexane extract of Hesperozygis ringens (Benth.) Epling through immersion bath

The growing increase in the fish farming sector has favored the establishment of bacterial outbreaks caused by Aeromonas hydrophila in several species. The hexane extract of Hesperozygis ringens (HEHR) (Lamiaceae) leaves increased the survival rate of silver catfish (Rhamdia quelen) experimentally infected by A. hydrophila. However, it is noteworthy that no reports have been found on the possible mechanisms of action of this extract in infected fish. This study aimed to evaluate the effect of the HEHR, administered through single immersion bath, on lipid peroxidation and antioxidant defenses in muscle and liver tissue of silver catfish challenged with A. hydrophila. The results showed that the oxidative status of silver catfish was altered, although oxidative stress was not triggered during the experiment. HEHR at 30 mg/L (HEHR30) was not characterized as a pro-oxidant agent in the presence of infection, unlike florfenicol and HEHR at 15 mg/L treatments in some cases. In short, HEHR30 provided an important increase in hepatic catalase activity, characterizing one of the possible mechanisms involved in the greater survival of fish experimentally infected by A. hydrophila. Additionally, HEHR30 did not induce lipid peroxidation, nor reduced antioxidant defenses of silver catfish infected or not by A. hydrophila.

In Vitro Antiviral and Anticancer Effects of Tanacetum sinaicum Essential Oil on Human Cervical and Breast Cancer

BACKGROUND

Cervical cancer has been linked to human papillomavirus (HPV) types 16 and 18. Essential oils (EOs) are vital natural products of plants with various therapeutic and biological properties.

OBJECTIVES

The purpose of this study is to investigate and assess Tanacetum sinaicum essential oil's possible antiviral and anticancer properties, with a focus on its in vitro effects on human cervical cancer and human breast adenocarcinoma cell lines.

MATERIALS AND METHODS

Tanacetum sinaicum EO was extracted via hydrodistillation (HD) and characterized using gas chromatography-mass spectrometry (GC-MS). MTT assay was used to determine the cell viability of Hela (a human epithelial cervical cancer) and MCF-7 (human breast adenocarcinoma) cell lines. Quantitative real-time polymerase chain reaction (PCR) was utilized to assess the antiviral efficacy of EO against HPV-16 and 18, and anti-metastatic characteristics. The biological activity of EO was assessed using Autophage and Cell genotoxicity via the comet assay.

RESULTS

EO is mostly composed of chrysanthenyl acetate, thujone, and verbenol. The cell viability was reduced after 24 hours of incubation at doses from 100 to 400 µg/ml. Concentrations of 800 to 3,200 µg/ml significantly inhibit cell growth. After a 24-hour incubation period, doses ranging from 100 to 400 µg/ml reduced cell viability from 62 to 72%. Concentrations of 800 to 3,200 µg/ml significantly suppress cell growth by over 95%. In MCF7 and HeLa cell lines, EO lowered virus copy numbers in a dose-dependent manner, with higher concentrations of the oil inhibiting virus replication more effectively. EO treatment increased the number of autophagosomes/autolysosomes and acidic vesicular organelles in both cell lines. On the HeLa and MCF7 cell lines, EO demonstrated antiproliferative and antimetastatic effects. The results demonstrated that EO had dose-dependent genotoxic effects on both cancer cell lines, as evidenced by DNA damage.

CONCLUSION

Tanacetum sinaicum EO is a prospective source of natural bioactive compounds that can be employed in pharmaceutical and medicinal applications due to its antiviral, antiproliferative, anti-metastatic and genotoxic properties.

Essential oil of Pterocarpus santalinus L. alleviates behavioral impairments in social defeat stress-exposed mice by regulating neurotransmission and neuroinflammation

BACKGROUND

Pterocarpus santalinus L. essential oil (PSEO) is traditionally employed for treating fever and mental aberrations. We aim to explore the antidepressant potential of intranasal PSEO in social defeat stress (SDS)-expose mice and identify its mechanisms and components.

METHODS

PSEO components were analyzed using gas chromatography-mass spectrometry (GC-MS). C57BL/6 mice underwent a 10-day SDS with intranasal PSEO (10, 20 mg/kg) for 21 days. Efficacy was evaluated through changes in behaviors and serum corticosterone (CORT), hippocampal neurotransmitter, and inflammatory cytokine levels. In vitro effects were examined using primary hippocampal neurons, PC12 and BV2 cells.

RESULTS

GC-MS identified 22 volatile compounds in PSEO, and (+)-ledene (16.7%), cedrol (13.5%), and isoaromadendrene epoxide (7.0%) as major components. PSEO (20 mg/kg) significantly reversed SDS-induced social withdrawal, increased open-area explorations in the open field test (OFT) and elevated plus maze (EPM) test, and reduced immobility time in the tail suspension test (TST) and forced swimming test (FST). PSEO downregulated serum CORT and hippocampal interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α levels, while increasing hippocampal gamma-aminobutyric acid (GABA), norepinephrine (NE), and serotonin (5-HT) levels. PSEO (0.1, 1, 10 µg/mL) reduced neurotoxicity and neuroinflammation in PC12 and BV2 cells, respectively. PSEO (10 µg/mL) enhanced glutamic acid decarboxylase 6 (GAD6)- and GABA B receptor 1 (GABABR1)-positive puncta in the hippocampal neurons and FM1-43 fluorescence intensity.

CONCLUSION

Intranasal PSEO exhibited antidepressant-like effects on SDS-exposed mice, potentially through modulating stress hormone, neurotransmission, and neuroinflammation. Further investigation into the pharmacokinetics, bioavailability, and mechanisms of (+)-ledene, cedrol, and isoaromadendrene epoxide is needed.

Antimicrobial activity of essential oils (Citrus bergamia Risso & Poiteau, Melaleuca alternifolia and Chenopodium botrys) on pathogen strains isolated in milk samples from mastitic sheep

The aim of this investigation was to study in vitro antibacterial activity of essential oils (EOs) (Citrus bergamia Risso & Poiteau, Melaleuca alternifolia and Chenopodium botrys) on pathogenic strains isolated in milk samples from mastitic sheep. The in vitro antibacterial activity showed that EOs induced higher bacterial inhibition against pathogens isolated in mastitic milk (Staphylococcus xylosus, Staphylococcus epidermidis, Streptococcus salivarius, Enterococcus faecium, Streptococcus agalactiae and Pseudomonas aeruginosa) than common antimicrobial agents used in veterinary medicine, with Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values significantly lower, excepted for P. Aeruginosa. The antibacterial activity of EOs has been attributed to the chemical composition of each phyto-complexes, constituted by monoterpenes, sesquiterpenes and their associated alcohols, identified by GC-MS analysis, with a synergic action in the bacterial cells. The results obtained confirmed in vitro antimicrobial activity of these EOs and their potential use in the treatment of sheep mastitis infection.

Pterodon emarginatus Seed Preparations: Antiradical Activity, Chemical Characterization, and In Silico ADMET Parameters of β-caryophyllene and Farnesol

The study of medicinal plants and their active compounds is relevant to maintaining knowledge of traditional medicine and to the development of new drugs of natural origin with lower environmental impact. From the seeds of the Brazilian plant Pterodon emarginatus, six different preparations were obtained: essential oil (EO), ethanol extract (EthE) prepared using the traditional method, and four extracts using solvents at different polarities, such as n-hexane, chloroform, ethyl acetate, and methanol (HexE, ChlE, EtAE, and MetE). Chemical characterization was carried out with gas chromatography, allowing the identification of several terpenoids as characteristic components. The two sesquiterpenes β-caryophyllene and farnesol were identified in all preparations of Pterodon emarginatus, and their amounts were also evaluated. Furthermore, the total flavonoid and phenolic contents of the extracts were assessed. Successively, the antiradical activity with DPPH and ORAC assays and the influence on cell proliferation by the MTT test on the human colorectal adenocarcinoma (HT-29) cell line of the preparations and the two compounds were evaluated. Lastly, an in silico study of adsorption, distribution, metabolism, excretion, and toxicity (ADMET) showed that β-caryophyllene and farnesol could be suitable candidates for development as drugs. The set of data obtained highlights the potential medicinal use of Pterodon emarginatus seeds and supports further studies of both plant preparations and isolated compounds, β-caryophyllene and farnesol, for their potential use in disease with free radical involvement as age-related chronic disorders.

Enhancing the Functional Properties of Tea Tree Oil: In Vitro Antimicrobial Activity and Microencapsulation Strategy

In the context of addressing antimicrobial drug resistance in periocular infections, Tea Tree Oil (TTO) has emerged as a promising therapeutic option. This study aimed to assess the efficacy of TTO against bacterial strains isolated from ocular infections, with a particular focus on its ability to inhibit biofilm formation. Additionally, we designed and analyzed microcapsules containing TTO to overcome certain unfavorable physicochemical properties and enhance its inherent biological attributes. The quality of TTO was confirmed through rigorous analysis using GC-MS and UV-Vis techniques. Our agar diffusion assay demonstrated the effectiveness of Tea Tree Oil (TTO) against ocular bacterial strains, including Corynebacterium spp., coagulase-negative Staphylococcus spp., and Staphylococcus aureus, as well as a reference strain of Staphylococcus aureus (ATCC 25923). Notably, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for all tested microorganisms were found to be 0.2% and 0.4%, respectively, with the exception of Corynebacterium spp., which exhibited resistance to TTO. Furthermore, TTO exhibited a substantial reduction in biofilm biomass, ranging from 30% to 70%, as determined by the MTT method. Through the spray-drying technique, we successfully prepared two TTO-containing formulations with high encapsulation yields (80-85%), microencapsulation efficiency (90-95%), and embedding rates (approximately 40%). These formulations yielded microcapsules with diameters of 6-12 μm, as determined by laser scattering particle size distribution analysis, and exhibited regular, spherical morphologies under scanning electron microscopy. Importantly, UV-Vis analysis post-encapsulation confirmed the presence of TTO within the capsules, with preserved antioxidant and antimicrobial activities. In summary, our findings underscore the substantial therapeutic potential of TTO and its microcapsules for treating ocular infections.

Myrcene: A Natural Compound Showing Anticancer Activity in HeLa Cells

γ-terpinene, α-terpinene, p-cymene, and myrcene are monoterpenes found in many essential oils extracted from a variety of plants and spices. Myrcene also occurs naturally in plants such as hops, cannabis, lemongrass, and verbena and is used as a flavoring agent in food and beverage manufacturing. In this research, the biological efficacy of γ-terpinene, α-terpinene, p-cymene, and myrcene was studied in human cell lines (HeLa, SH-SY5Y, and HDFa). Cytotoxicity, cell proliferation, cell migration, and morphology assays were performed to obtain detailed information on the anticancer properties. Our results show that myrcene has potential biological activity, especially in HeLa cells. In this cell line, it leads to an arrest of proliferation, a decrease in motility and morphological changes with loss of sphericity and thickness, and DNA damage. In addition, the interaction of γ-terpinene, α-terpinene, p-terpinene, and myrcene with calf thymus DNA (ct-DNA) was studied by UV-visible spectrophotometry. DNA binding experiments show that only myrcene can interact with DNA with an apparent dissociation constant (Kd) of 29 × 10-6 M.