Essential Oils: Chemistry and Pharmacological Activities

Residual depletion of eugenol as an anesthetic in growing phase pacu (Piaractus mesopotamicus)

The aim of this study was to evaluate the pharmacokinetics of eugenol in pacu (Piaractus mesopotamicus) juveniles following exposure to an immersion bath. Pacu juveniles (n = 42) with an average weight of 546.40 ± 74.51 g and total length of 25.43 ± 1.52 cm were subjected to a bath with 100 mg L-1 eugenol previously dissolved in 95% ethanol (1:10). After a 10-min immersion, the fish were transferred to anesthetic-free aquaria for recovery. Blood, kidney, muscle, spleen, gills, and brain samples were collected at intervals 0, 0.5, 1.0, 3.0, 6.0, 12.0, and 24.0 h post-anesthesia. Pharmacokinetic parameters were calculated using non-compartmental methods. The highest eugenol concentrations were recorded immediately after anesthesia (0 h) in all tissues, in descending order: plasma > kidney > muscle > spleen > gills > brain. The plasma and brain half-lives of eugenol were 1.12 h and 0.73 h, respectively, with elimination constants of 0.62 and 0.95 per hour. In muscle and kidney tissues, the half-lives were 0.14 h and 0.09 h, with elimination constants of 4.97 and 7.44 per hour, respectively. In the spleen and gills, the half-lives were 0.21 h and 0.23 h, with elimination constants of 3.26 and 3.07 per hour. In conclusion, eugenol is rapidly absorbed and eliminated in growing phase pacu, reaching peak concentrations soon after anesthesia and showing a significant reduction up to 24 h.

Chemical Composition, Antifungal, and Cytotoxic Activities of Essential Oil From Brunfelsia uniflora Leaves

This study aimed to determine the phytochemical composition of the essential oil (EO) from Brunfelsia uniflora leaves and to evaluate its antifungal and cytotoxic activities. The EO was obtained by hydrodistillation and analyzed using GC-MS and GC-FID, leading to the identification of 39 compounds. The composition was predominantly terpenoid (65.7%), followed by non-terpenoid constituents (31.2%). The major compounds identified included phytol (13.2%), oleic acid (10.5%), phenylethyl alcohol (9.2%), and γ-eudesmol acetate (7.0%). The antifungal activity of the EO was evaluated against Candida species using the broth microdilution method. The EO exhibited strong inhibitory effects against C. albicans and C. orthopsilosis (MIC = 62.5 µg/mL), moderate activity against C. glabrata and C. rugosa (MIC = 250 µg/mL), and weak activity against C. tropicalis (MIC = 1000 µg/mL). The cytotoxic effects of the EO were assessed in human tumor cell lines (HeLa, MCF-7) and a nontumor fibroblast line (GM07492A). The EO demonstrated selective cytotoxicity toward HeLa (IC50 = 21.9 µg/mL) and MCF-7 (IC50 = 25.7 µg/mL), while exhibiting lower toxicity to fibroblasts (IC50 = 131.9 µg/mL). The selectivity indices (SI = 6.0 for HeLa, 5.1 for MCF-7) suggest its potential as a promising therapeutic candidate for antifungal and anticancer applications.

The Effect of Different Extraction Techniques on the Bioactive Characteristics of Dill (Anethum graveolens) Essential Oil

This study explores the extraction of Anethum graveolens essential oil (EO) using advanced techniques, including Superheated Steam Extraction (SHSE), and compares them with traditional methods such as Hydro Distillation (HD), Steam Distillation (SD), and Supercritical Carbon Dioxide Extraction (SCF-CO2). The novelty of this research lies in the comprehensive evaluation of SHSE, a relatively underexplored method, for its effectiveness in enhancing both yield and biological activities of the EO. This study provides a detailed comparative analysis of antioxidant and antimicrobial properties across different extraction methods. The SHSE method yielded essential oil with the highest antioxidant activity, including DPPH scavenging (87.48%) and total antioxidant capacity (measured by FRAP, 163.06 mg/L), outperforming traditional methods. The EO's high content of key components such as carvone, limonene, and dillapiole significantly contributes to its enhanced biological activities. These findings underscore the superior efficacy of SHSE in extracting essential oils, offering new insights into their potential applications in health and wellness, which set this study apart from previous work.

Plant-Derived Monoterpene Therapies in Parkinson's Disease Models: Systematic Review and Meta-Analysis

Monoterpenes (MTs) are plants' secondary metabolites and major components of essential oils (EOs), widely used in the pharmaceutical industry. However, its neuroprotective effects, particularly in Parkinson's disease (PD) have not been fully demonstrated. PD is a progressive neurological disorder marked by dopaminergic neuron loss in the substantia nigra, motor symptoms being the most reported ones. This review evaluates the evidence supporting the use of MTs as potential neuroprotective agents. PubMed, SCOPUS, Google Scholar, and ScienceDirect databases were searched for articles on MTs in murine models with any type of administration. The PRISMA guidelines were followed. After screening 405 records, 32 were included in the systematic review and 30 were included in the meta-analysis. Fifteen MTs, commonly found in EOs, were identified as potential therapeutic agents for PD. The meta-analysis revealed that MTs administration improved motor performance, increased tyrosine hydroxylase levels, reduced oxidative stress markers (malondialdehyde) and proinflammatory cytokines (IL-6, IL-1, TNF-α), and enhanced antioxidant enzymes (catalase, superoxide dismutase) in parkinsonian animals. The antioxidant and anti-inflammatory properties of MTs appear to be key mechanisms in mitigating dopaminergic neurodegeneration. However, further clinical research is essential to translate these findings into practical applications.

Utilizing Essential Oil Components as Natural Antifungal Preservatives in the Active Packaging of Bread

The use of essential oil components as natural antifungal preservatives in the active packaging of bread is an innovative approach that leverages the antimicrobial properties of these compounds to extend the shelf life of bread and ensure its safety. The aim of the present work was the thorough investigation of the antioxidant properties and antifungal activity of low-density polyethylene (LDPE or PE) nanocomposite films with organically modified montmorillonite (O) loaded with carvacrol (C) or thymol (T) as a function of time, starting from 2 months and concluding at 12 months. The films PE_OC and PE_OT were prepared through the evaporation/adsorption method, a green methodology developed by our group compatible with food packaging. For a comprehensive analysis of the synthesized films' oxygen permeability (OTR), measurements were employed, indicating that the incorporation of clay-bioactive nanocarriers into LDPE films reduced their oxygen permeability. A thorough analysis in terms of the antioxidant activity of the films was assessed at various intervals (2, 3, 6, and 12 months), showing high antioxidant activity for films PE_OC10 and PE_OT10 (polyethylene with 10% wt. organically modified montmorillonite loaded with carvacrol or thymol), even at 12 months. Based on the overall analysis, the PE_OC10 film was identified as the most effective option in the antifungal evaluation conducted using white bread, demonstrating substantial inhibition of fungal growth for up to six months.

Exploration of advanced omics tools and resources for the improvement of industrial oil crops

The rapid advancement in the field of omics approaches plays a crucial role in the development of improved industrial oil crops. Industrial oil crops are important for many sectors like food processing, biofuels, cosmetics, and pharmaceuticals, making them indispensable contributors to global economies and these crops serve as vital elements in a multitude of industrial processes. Significant improvements in genomics have revolutionized the agricultural sector, particularly in the realm of oil crops. Cutting-edge advancements have facilitated the efficient sequencing of genomes for key commercial oil crops. This breakthrough not only enhances our understanding of the genetic makeup of these crops but also empowers breeders with invaluable insights for targeted genetic manipulation and breeding programs. Moreover, integrating transcriptomics with genomic data has assisted in a new era of precision agriculture. This approach provides an in-depth understanding of molecular mechanisms involved in traits of interest, such as oil content, yield potential, and resistance to biotic and abiotic stresses. Proteomics methods are instrumental in deciphering the intricacies of protein structure, interactions, and function, while metabolomics and ionomics shed light on the intricate network of metabolites and ions within biological systems. Each omics discipline offers unique insights, and their integration holds the promise of enriching our understanding and furnishing invaluable insights for enhancing oil crops. This review delves into the efficacy and constraints of various omics approaches in the context of refining industrial oil crops. Moreover, it underscores the importance of multi-omics strategies and explores their convergence with genetic engineering techniques to cultivate superior oil crop varieties.

Recovery of Bioactive Compounds from the Biomass of Aromatic Plants After Distillation Using NADES: A Sustainable Alternative Extraction Method

The extraction processes for medicinal plants, particularly the distillation of aromatic plants, generate significant quantities of by-products, consisting of fibrous biomass and hydrosols. These by-products pose challenges for disposal and recovery. Consequently, it is imperative to make the entire highly energy-intensive process more sustainable by valorizing all derivatives. This study aims to recover polyphenols from the exhausted biomasses of Artemisia dracunculus, Echinacea purpurea, Helichrysum italicum (from the Asteraceae family), and Lavandula angustifolia, Lavandula × intermedia, Melissa officinalis, Salvia officinalis, Salvia sclarea, and Salvia rosmarinus (from the Lamiaceae family) after steam distillation. The residual biomasses were extracted using ethanol (conventional solvent) and different natural deep eutectic solvents (NADES) composed of choline chloride in combination with citric and lactic acids at different molar ratios. The NADES containing choline chloride and lactic acid at the molar ratio 1:1 (CLA11) exhibited the highest recovery of representative phenols of the plants, namely chicoric and rosmarinic acids. The CLA11 solvent demonstrated a stronger extractive capacity compared to ethanol in all the biomasses belonging to the Asteraceae and Lamiaceae families. Specifically, CLA11 extracts showed a higher number of compounds in UHPLC-HRMS and greater concentrations of chicoric and rosmarinic acids determined by HPLC-DAD than ethanol extracts. In conclusion, NADES were demonstrated to be a viable alternative system for the recovery of bioactive compounds that could be used to formulate new products for the food, pharmaceutical, and cosmetic industries. Moreover, the use of NADES can enhance the sustainability of the whole production chain of essential oils being environmentally friendly.

The role of essential oils as eco-friendly strategy to control biofilm collected in the Colosseum (Rome, Italy)

The control of biodeteriogenic microorganisms is essential for the management of heritage sites. Many conventional biocides are no longer available because they have lost their efficacy or have been withdrawn from the market due to their danger to humans and the environment. Therefore, new effective and sustainable biocides are needed, such as plant extracts that could be a good alternative. In this study, essential oils (EOs) of Ocimum basilicum L., Cinnamomum verum Presl, Lavandula angustifolia Mill., Origanum vulgare L., Thymus vulgaris L. and Melaleuca alternifolia Maiden & Betche were tested as green biocides against microorganisms collected from biofilms in the hypogeum of the Colosseum (Rome, Italy). Biocidal screening was first carried out on phototrophic microorganisms grown on BG11 agar culture medium. The efficacy was assessed by measuring photosynthetic activity with a mini-PAM portable fluorometer, and by determining morphological changes or the absence of autofluorescence using light microscopy and confocal laser scanning microscopy. The most effective EOs against phototrophs were further tested to inhibit the growth of heterotrophic fungi and bacteria in order to identify those with a broad-spectrum action. The EOs of cinnamon, oregano and thyme at 5% concentration (v/v) were the most effective against the microorganisms isolated from the biofilms in the Colosseum. These EOs represent a green alternative to traditional chemical biocides due to their activity against a wide range of microorganisms and their complex composition which suggests the potential to reduce the risk of microbial resistance. KEY POINTS: Biofilms collected from the Colosseum hypogeum were characterized EOs tested as biocides against phototrophs and heterotrophs in Colosseum biofilms. Cinnamon, oregano, and thyme EOs show broad-spectrum action at 5% concentration.

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

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

Chemical Characterization and Antibiotic-Enhancing Activity of the Essential Oils of Propolis of Melipona quadrifasciata quadrifasciata

This study investigated the chemical composition and potential antibacterial activity of the essential oils from the propolis of Melipona quadrifasciata quadrifasciata (MQP) in samples collected from the cities of Paranaguá and Guaratuba, Paraná, Brazil, during summer and winter. The chemical composition of the oils was analyzed by GC-MS, and their minimum inhibitory concentration (MIC) was determined against standard ATCC strains and some clinical isolates (Escherichia coli 06 and Staphylococcus aureus 10). The essential oils' MICs were determined using microdilution in 96-well plates and showed no significant antibacterial activity (MIC ≥ 1024 μg/mL) when used alone. However, the essential oils enhanced the action of norfloxacin, gentamicin, and ampicillin, especially against S. aureus 10. The chemical analysis identified 68 compounds, with β-bisabolene and β-caryophyllene as the predominant constituents. Subsequently, the antibiotic-enhancing activity against the clinical isolates was evaluated. The composition of the MQP oils varied according to seasonality and location, influenced by the microclimates of the cities. The results highlight the importance of MQP oils in enhancing antibiotic activity, particularly against Gram-positive bacteria, despite the lack of significant standalone antibacterial activity.

Phytochemistry and Anti-Inflammatory and Antioxidant Activities of Cinnamomum osmophloeum and Its Bioactive Constituents: A Review

Cinnamomum osmophloeum, commonly known as indigenous cinnamon, is a tree species native to Taiwan's hardwood forests. It has been extensively investigated for its chemical composition and bioactivities. Several reports have shown that C. osmophloeum leaves are rich in aromatic oils, which are grouped into various chemotypes based on their major constituents. Components of the volatile oils included phenylpropanoids, monoterpenoids, sesquiterpenoids, phenols, coumarins, and other miscellaneous compounds. In addition, other secondary metabolites previously identified in this species included flavonol glycosides, phenolic acids, lignans, proanthocyanidins, and cyclopropanoids. C. osmophloeum is widely recognized for its medicinal and industrial applications, particularly its essential oils. In general, essential oils exhibit remarkable anti-inflammatory and antioxidant actions, enabling them to modulate key inflammatory mediators and neutralize free radicals. This review explored the phytochemical composition of the essential oils and extracts from C. osmophloeum as well as therapeutic potential of this species, focusing on the action mechanisms and clinical potential. We hope that this review will contribute to a better understanding of the biological effects of this plant and its potential applications in the management of conditions associated with inflammation and oxidative stress.

Exploring the mechanism of action of huoermai essential oil for plateau insomnia based on the camp/CREB/BDNF/gabaergic pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional Huoermai therapy is a treatment for insomnia used by the Tibetan people living on the Tibetan plateau in China. This therapy involves the use of Myristica fragrans Houtt. and Carum carvi L., along with fomentation and massage, and has shown significant clinical effects. However, the mechanism of how Huoermai therapy treats plateau insomnia needs further clarification.

AIM OF THE STUDY

This study aimed to investigate the mechanism of action of Huoermai essential oil (HEO) in treating plateau insomnia, focusing on the cAMP/CREB/BDNF/GABAergic pathway.

METHODS

The major components of Huoermai essential oil were identified by Gas chromatography-mass spectrometry (GC-MS) for subsequent network pharmacology analysis. Proteomics techniques were employed to pinpoint disparities in brain tissue protein expression in a mouse model of plateau insomnia following Huoermai therapy administration, in conjunction with network pharmacology to forecast pathways related to hypoxia and insomnia. Plateau insomnia mouse model was established and the therapeutic impact of Huoermai essential oil was evaluated. Hematoxylin & Eosin staining(HE) was conducted to observe pathological damage to the cortex, hippocampus, thalamus and hypothalamus structures. Changes in serotonin (5-HT), melatonin (MT), adenosine (AD), cyclic adenosine monophosphate (cAMP) and malondialdehyde (MDA) levels in mouse brain tissue were gauged through enzyme-linked immunosorbent assay (ELISA) to assess sleep status and oxidative stress levels in mice. Molecular docking was employed to anticipate the target binding energy of Huoermai essential oil constituents. ELISA and Western Blot (WB) were used to ascertain the expression of cAMP/CREB/BDNF/GABAergic pathway.

RESULTS

The results indicated that HEO positively impacted intermittent hypobaric hypoxia-induced plateau insomnia in mice. Histological examination results showed that HEO ameliorated neuronal damage in specific regions of the brain affected by plateau insomnia, such as the cortex, hippocampus, thalamus, and hypothalamus. Through GC-MS analysis, 56 volatile oil components were identified. Subsequently, a combined network pharmacology and proteomics analyses led to selecting the cAMP/CREB/BDNF/GABAergic pathway for further study. ELISA experiments demonstrated that HEO treatment increased GABA and MT levels while significantly reducing 5-HT and adenosine levels in brain tissue of mice with plateau insomnia. WB results revealed that HEO ameliorated plateau insomnia by suppressing the hyperactivation of the cAMP pathway, increasing brain-derived neurotrophic factor (BDNF) levels and B-cell lymphoma-2 (BCL-2) expression, and alleviating hypoxia-induced oxidative stress. Moreover, molecular docking results showed strong binding affinity of all pharmacological components to their targets and proteins in the brain.

CONCLUSION

These results indicate that HEO significantly prolongs sleep duration in plateau insomniac mice and treats plateau insomnia by modulating levels of sleep-related regulators, modulating the cAMP pathway, increasing GABA receptor expression, and improving neuronal survival and anti-apoptosis.

Essential Oils as Antimicrobials against Acinetobacter baumannii: Experimental and Literature Data to Definite Predictive Quantitative Composition-Activity Relationship Models Using Machine Learning Algorithms

Essential oils (EOs) exhibit a broad spectrum of biological activities; however, their clinical application is hindered by challenges, such as variability in chemical composition and chemical/physical instability. A critical limitation is the lack of chemical consistency across EO samples, which impedes standardization. Despite this, evidence suggests that EOs with differing chemical profiles often display similar (micro)biological activities, raising the possibility of standardizing EOs based on their biological effects rather than their chemical composition. This study explored the relationship between EO chemical composition and antibacterial activity against carbapenem-resistant Acinetobacter baumannii. A dataset comprising 82 EOs with known minimal inhibitory concentration values was compiled using both experimental results and literature data sourced from the AI4EssOil database (https://www.ai4essoil.com). Machine learning classification algorithms including Support Vector Machines, Random Forest, Gradient Boosting, Decision Trees, and K-Nearest Neighbors were employed to generate quantitative composition-activity relationship models. Model performance was assessed using internal and external prediction accuracy metrics with the Matthews correlation coefficient as the primary evaluation metrics. Features importance analysis, based on the Skater methodology, identified key chemical components influencing EO activity. The single chemical components limonene, eucalyptol, alpha-pinene, linalool, beta-caryophyllene, nerol, beta-pinene, neral, and carvacrol were highlighted as critical to biological efficacy. The predictive capacity of the ML models was validated against a test set of freshly extracted and chemically characterized EOs. The models demonstrated a 91% prediction accuracy for new EO samples, and a strong correlation was observed between predicted features importance and experimental inhibitory values for six selected pure compounds (limonene, eucalyptol, alpha-pinene, linalool, carvacrol, and thymol). Additionally, the machine learning approach was extended to cytotoxicity data from 3T3-Swiss fibroblasts for 61 EOs. The analysis revealed the potential to design EOs with both high antibacterial activity and low cytotoxicity through blending or selective enrichment with identified key components. These findings pave the way for biologically standardized EOs, enabling their rational design and optimization for clinical applications.

Synergistic Antibiofilm Effects of Chestnut and Linden Honey with Lavender Essential Oil Against Multidrug-Resistant Otitis Media Pathogens

BACKGROUND/OBJECTIVES

Bacterial resistance to antibiotics is a major problem in healthcare, complicated by the ability of bacteria to form biofilms. Complementary therapy for infectious diseases can rely on natural substances with antibacterial activity, e.g., essential oils and honeys. The aim of the study was to investigate the effects of linden and chestnut honeys, lavender essential oil, and their combinations against the multidrug-resistant otitis media pathogens Haemophilus influenzae, H. parainfluenzae, Moraxella catarrhalis, Pseudomonas aeruginosa, and Streptococcus pneumoniae. The efficacy of these natural substances was compared with each other and antibiotics used in clinical practice.

METHODS

Microscopic pollen analysis and physicochemical traits were used to confirm the botanical origin of honey samples. The antibiotic sensitivity of bacteria was tested with a disk diffusion assay. Minimum inhibitory concentrations were determined using a microdilution assay. A 24 h immature biofilm eradication test was performed with a crystal violet assay. The efficacy of combinations was tested with a checkerboard titration method. The DNA release of damaged bacterial cells was measured using a membrane degradation assay.

RESULTS

Lavender essential oil displayed more potent antibacterial activity compared to the honey samples. However, honey-essential oil combinations showed higher inhibition rates for biofilm eradication, with P. aeruginosa being the most resistant bacterium. The combined use of chestnut honey and lavender oil resulted in a higher degree of membrane degradation in a shorter time, and their synergistic effect was proven with checkerboard titration.

CONCLUSIONS

The combination of linden or chestnut honey with lavender essential oil was shown to be effective in the eradication of a 24 h immature biofilm formed by H. parainfluenzae, M. catarrhalis, and S. pneumoniae.

Prodrug Self-Assemblies Based on Plant Volatile Aldehydes with Improved Stability and Antimicrobial Activity Against Plant Pathogens

Plant volatile aldehydes (PVAs) such as cinnamaldehyde (Cin), citral (Cit), citronellal (Citr), and perillaldehyde (Per) have broad-spectrum antimicrobial activity and show great potential in agricultural sustainable production. However, most PVAs not only have very high volatility but also are easily degradable in environment, which seriously restricts their wide application. To address the inherent problems with PVAs, four prodrugs based on PVAs are fabricated by conjugating individually Cin, Cit, Citr, and Per to sodium bisulfite (Sod) through a simple addition reaction and subsequently self-assembled into nanoparticles (prodrug self-assemblies) in aqueous solutions. The results showed that pH of 7 and temperature of 35 °C are the optimal conditions for the formation of the prodrug self-assemblies with the highest self-assembly rates. The prepared prodrug self-assemblies are spherical nanoparticles with average particle sizes of 100-200 nm, almost no volatilization, and high surface activity and stability, and can respond to acidic and redox microenvironments to release PVAs. The prodrug self-assemblies showed synergistic antimicrobial activities against Sclerotinia sclerotiorum and Penicillium digitatum, and good biological safety to plants. Therefore, these findings have important implications for the efficient utilization of PVAs in agriculture, ensuring the safety of the ecological environment and realizing the sustainable development of agriculture.

The neuroprotective role of volatile oils: insights into chemical profiles, characteristics, neurochemical mechanisms, and preclinical studies in Alzheimer's disease

Volatile oils (VOs), synonymously termed essential oils (EOs), are highly hydrophobic liquids obtained from aromatic plants, containing diverse organic compounds for example terpenes and terpenoids. These oils exhibit significant neuroprotective properties, containing antioxidant, anti-inflammatory, anti-apoptotic, glutamate activation, cholinesterase inhibitory action, and anti-protein aggregatory action, making them potential therapeutic agents in managing neurodegenerative diseases (NDs). VOs regulate glutamate activation, enhance synaptic plasticity, and inhibit oxidative stress through the stimulation of antioxidant enzymes. They also reduce inflammation by inhibiting key inflammatory mediators and enzymes. Furthermore, VOs prevent neuronal apoptosis by modulating apoptosis-related proteins and caspases. Their anti-protein aggregation potential helps mitigate the accumulation of misfolded proteins, a hallmark of neurodegenerative disorders. Additionally, VOs inhibit cholinesterase enzymes, increasing acetylcholine levels, and improving neuronal communication. In addition to their neuroprotective action, it also exerts some toxic effects, such as genotoxicity, hepatotoxicity, embryotoxicity, and hypersensitivity, which are most commonly caused by the presence of monoterpenes in the volatile oils. This review examines the diverse functions of vasoactive oxidants (VOs) in neuroprotection, underscoring their therapeutic promise for various neurological conditions, with a particular emphasis on Alzheimer's disease.

Induction by caterpillars of stored and emitted volatiles in terpene chemotypes from populations of wild cotton (Gossypium hirsutum)

BACKGROUND

Upland cotton (Gossypium hirsutum) plants constitutively store volatile terpenes in their leaves, which are steadily emitted at low levels. Herbivory leads to a greater release of these stored volatiles. Additionally, damaged plants increase the accumulation of volatile terpenes in their leaves and begin to synthesize and emit other terpenes and additional compounds. This has been well characterised for cultivated G. hirsutum, but little is known about volatile production in response to herbivory in wild populations. We investigated how damage by a generalist herbivore species, the beet armyworm (Spodoptera exigua), affects leaf-stored and emitted volatiles in wild G. hirsutum plants and compared the responses of two known chemotypes. Wild cotton plants were grown in a greenhouse from seeds collected from four distinct locations covering sixteen populations, along the Yucatan coast (Mexico), from where this cotton species originates. We assessed whether the differences in leaf terpene profiles between the two chemotypes persisted upon herbivory, in leaves and in headspace emissions, and whether these chemotypes also differed in the production and release of herbivory-induced volatiles. In addition to chemotypic variation, we further investigated intraspecific variation in the volatile response to herbivory among genotypes, populations, and the four geographic regions.

RESULTS

The difference between the two chemotypes persisted after herbivory in the stored volatile profile of induced leaves, as well as in the emissions from damaged plants. Therefore, wild cotton chemotypes may differ in their airborne interactions with their environment. The specific terpenes distinguishing these chemotypes showed a weak inducibility, raising questions about their functions. Herbivory triggered changes in stored and emitted volatiles similar to what is known for cultivated varieties of G. hirsutum. However, we report for the first time on the emission of volatile aldoximes by cotton plants, which were only detected in the headspace upon herbivory, and displayed chemotypic and interpopulation variation. Intraspecific variation was also observed in the induced emissions of nitriles and certain terpenes. Moreover, chemotypes differed in their induction of (E)-β-ocimene stored in the leaves.

CONCLUSIONS

This comprehensive insight into herbivore-induced volatiles of wild cotton reveals variation in production and emission among populations. A full understanding of their ecological role may help in the development of future pest-management strategies for cotton crops.

Phytochemical profile and nematicidal potential of essential oil from Algerian wild Origanum vulgare subsp. glandulosum Defs

Background/aim

The root gall nematode Meloidogyne incognita constitute the most damaging species that infects many crops in Algeria. The intense use of harmful agricultural chemical products has incited research to develop alternative methods with natural and ecological advantages like essential oils extracted from plants. The objective of this study was to evaluate the efficacy of Origanum vulgare subsp. glandulosum Desf. (Lamiaceae) essential oil on the development of the root-knot nematode M. incognita in potted tomatoes.

Materials and methods

In pot trials, we assessed the activity of O. vulgare subsp. glandulosum essential oil at two concentrations of 0.75 and 0.37 mg/L against M. incognita. These dilutions were applied in two treatments to soil: the preventive treatment (pretomato planting), and the curative treatment (posttomato planting), using an artificially inoculated tomato under controlled conditions.

Results

The application of O. vulgare subsp. glandulosum essential oil was very effective at the pretomato planting treatment compared to the chemical treatments, and the inoculated control. We noted a reduction in number of roots and soil juveniles, galling index, and an increase in the tomato root and stem weights. The phytochemical screening of O. vulgare subsp. glandulosum revealed the presence of five classes of bioactive compounds (glycosides, saponins, flavonoids, tannins, and gallic tannins).

Conclusion

This study showed a potential nematicidal effect of O. vulgare subsp. glandulosum essential oil on root-knot nematode.

Essential oils from Amorpha fruticosa against hepatocellular carcinoma based on network pharmacology

BACKGROUND

Amorpha fruticosa was used for treating burn, ambustion, carbuncle, and eczema in the traditional Chinese medicine. Although more and more attention has been paid to its biological activity recently, the antitumor activities of the essential oils (EOs) extracted from its leaves (AFLEO) and flowers (AFFEO), and their molecular mechanisms have never been reported up to now. The objective of present study was to examine the chemical compositions of AFLEO and AFFEO, then investigate the effects and pharmacological mechanism of EOs against hepatocellular carcinoma (HCC).

METHODS

The chemical compositions of EOs were examined using gas chromatography-mass spectrometry (GC-MS). The inhibitory effect of the EOs on HCC was evaluated by MTT assay. The detected components of AFLEO and AFFEO were performed ADME screening to examine their drug-likeness. Then a PPI network, compound-target network, compound-target-pathway network, gene ontology, and KEGG enrichment for HCC were applied to identify the targets and pathways for AFLEO and AFFEO against HCC. Molecular docking of the main components and their targets was performed to predict the binding affinity. Western blotting was used to verify the results.

RESULTS

30 components were identified from AFLEO, while 22 components from AFFEO. Both AFLEO and AFFEO inhibited the proliferation of HCC cells in a time and dose-dependent manner. 10 compounds of AFLEO and 9 compounds of AFFEO were screened out for further analysis. 28 hub targets of AFLEO and 40 hub targets of AFFEO were detected by PPI network. KEGG analysis revealed that pathways in cancer, chemical carcinogenesis - receptor activation and proteoglycans in cancer were related to the EOs against HCC. Molecular docking confirmed that the main component of the EOs has high affinity to the targets of HCC.

CONCLUSIONS

AFLEO and AFFEO may suppress HCC by acting on multiple targets and regulating multiple pathways.

Binary Combinations of Essential Oils: Antibacterial Activity Against Staphylococcus aureus, and Antioxidant and Anti-Inflammatory Properties

Background: The lack of new antimicrobial drugs and increased antimicrobial resistance has focused attention on the employment of essential oils (EOs) in human and veterinary medicine. The aim of this study was to test new binary associations between known and uncommon EOs. Methods: EOs from Origanum vulgare L., Juniperus communis L., Cistus ladaniferus L., Citrus aurantium L. var. amara were tested individually and in binary combinations to study, as follows: antibacterial activity against Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA) and Escherichia coli; antioxidant capacity via redox-based assays (DPPH, ABTS and FRAP); and anti-inflammatory activity via the bovine serum albumin denaturation inhibition assay. Results: O. vulgare L. showed good antibacterial activity against all strains (MIC = 0.03-0.12%, v/v), followed by C. ladaniferus L., and also had the best antioxidant and anti-inflammatory activities. Synergistic and additive effects were observed for the EO combinations O. vulgare L./C. ladaniferus L. and O. vulgare L./J. communis L. against S. aureus and MRSA, respectively. A reduction in biofilm was noted. Antioxidant and anti-inflammatory activities were also detected. Conclusions: The results suggest that EO combinations may be a promising strategy in veterinary settings for the treatment of infectious diseases caused by S. aureus, including drug-resistant and biofilm-forming strains accompanied by oxidative stress and inflammation.

Exploring Natural Deep Eutectic Solvents (NADES) for Enhanced Essential Oil Extraction: Current Insights and Applications

Essential oils (EOs) are highly valued in the cosmetic and food industries for their diverse properties. However, traditional extraction methods often result in low yields, inconsistent compositions, lengthy extraction times, and the use of potentially harmful solvents. Natural deep eutectic solvents (NADES) have emerged as promising alternatives, offering advantages such as higher efficiency, cost-effectiveness, biodegradability, and tunable properties. This review explores the application of NADES in enhancing EO extraction, focusing on current methodologies, key insights, and practical applications. It examines the factors that influence EO extraction with NADES, including the optimization of their physicochemical properties, extraction techniques, operational conditions, and the role of sample pretreatment in improving efficiency. Additionally, this review covers the chemical characterization and biological activities of EOs extracted using NADES. By providing a comprehensive overview, it highlights the potential of NADES to improve EO extraction and suggests directions for future research in this field.

Evaluating the multifaceted bioactivity of Syzygium aromaticum essential oil: the central role of eugenol

Background/aim

Syzygium aromaticum L. is a versatile plant traditionally used to treat digestive and respiratory issues, improve oral health, and relieve pain, particularly in regions such as Southeast Asia, South Asia, and parts of the Middle East. Its essential oil (EO), predominantly composed of eugenol, is rich in bioactive compounds. This study aims to clarify the specific contribution of eugenol to the antioxidant, antibacterial, antifungal, and insecticidal activities of S. aromaticum EO by comparing their individual effects. Additionally, density functional theory (DFT) calculations were employed to examine the antioxidant mechanism of eugenol and its role in enhancing the overall activity of the EO.

Materials and methods

The EO was obtained from S. aromaticum and analyzed using GC-MS to determine its composition. Antioxidant activity was assessed through the DPPH scavenging assay. Antibacterial and antifungal activities were evaluated using the disk diffusion method against various strains, while insecticidal and repellent effects were tested on Bruchus lentis at different concentrations and exposure times. Antioxidant mechanisms were investigated using DFT calculations.

Results

The findings underscore the strong antioxidant, antibacterial, antifungal, and insecticidal properties of S. aromaticum EO, with eugenol identified as the primary active component driving the antioxidant and insecticidal effects. Additionally, eugenol has been found to exhibit moderate scavenging activity in lipid media. However, its activity is higher in polar media, with a k overall = 1.70 ⊠ 106 M-1s-1 comparable to that of ascorbic acid. The single-electron transfer mechanism from the deprotonated state was found to play a decisive role under these conditions.

Conclusion

S. aromaticum EO exhibits remarkable antioxidant, antibacterial, antifungal, and insecticidal activities. A significant portion of these properties can be attributed to the presence of eugenol. This suggests that eugenol plays a critical role in the EO's overall efficacy, making S. aromaticum a promising candidate for applications in natural health products, pharmaceuticals, and agricultural pest management.

In Situ Gelling Dexamethasone Oromucosal Formulation: Physical Characteristics Influencing Drug Delivery

The study focuses on the development of an in situ gelling dexamethasone (DEX) oromucosal formulation designed for the treatment of aphthous stomatitis. Three series of formulations were prepared; a first series containing DEX suspended, a second series containing DEX and, in addition, mint essential oil (EO), and a third series containing EO and DEX solubilized in propylene glycol (PG). In the composition, polymers in the role of mucoadhesive agent were interchanged (hydroxypropyl methylcellulose (HPMC), hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC), methyl cellulose (MC), carboxymethyl cellulose (CMC), and sodium carboxymethyl cellulose (NaCMC). Specifically, DEX was incorporated at a concentration of 0.1% (w/w) in each formulation. The influence of mint EO and DEX solubilization on the physical properties (pH measurements, rheological analysis, swelling ability, and texture analysis) and in vitro drug release was studied. Key findings revealed that HPMC-based formulation containing mint EO and PG exhibited best swelling properties (700 ± 46% after 5 h), adequate adhesiveness and in vitro drug release (34.7 ± 5.9%). Furthermore, the irritation potential assessed via the hen's egg test on the chorioallantoic membrane (HET-CAM) demonstrated low irritancy risk. Finally, Fourier-transform infrared spectroscopy (FT-IR) showed no incompatibility between DEX and excipients. Overall, the research highlights the potential of mucoadhesive systems in improving the therapeutic efficacy of oromucosal drug delivery for managing painful oral lesions.

The Role of Essential Oils on Sleep Quality and Other Sleep-related Issues: Evidence from Clinical Trials

Essential oils (EOs) are a volatile mixture of bioactive compounds extracted from aromatic plants. The composition of EOs varies, which majorly depends on the extraction methods and plant parts. Aromatherapy using EOs has been reported for its several beneficial effects in humans. Aromatherapy is considered a complementary and/ or adjuvant therapeutic approach for treating several illnesses, especially to improve mental health and well-being. The incidence of sleep disorders, specifically insomnia, is nowadays increased, possibly due to urbanization and lifestyle. The studies showed that EOs-based treatments using lavender EO, bergamot EO, cinnamon EO, and rosemary EO (alone or in combinations) could improve sleep quality, duration, and deprivation in healthy subjects and patients, those who suffer from sleep-related issues. The current manuscript details the outcomes of EO-based treatments on the sleep quality of humans and the possible mechanisms associated with the health-promoting properties of EOs. Also, the toxicity and adverse effects of EOs have been discussed. The study indicated that EOs are potent adjuvant therapeutic candidates to manage mood-associated complications in humans. Moreover, the aromatherapeutic field requires detailed studies on toxicity and dose determination, which could provide safe and effective therapeutic results.

A review on essential oils: A potential tonic for mental wellbeing in the aging population?

Mental wellbeing is crucial to a good quality of life. With progression in life, mental health can deteriorate, leading to multiple disorders, such as depression, anxiety, stress, and insomnia. Essential oils, from various sources, have a long history of use in aromatherapy. Herein, we review the current literature related to the psychological effects of essential oils, emphasizing their impact on mood regulation, stress reduction, sleep disturbances, and cognitive function. Various mechanisms, such as alterations to the neurotransmitter system, endocrine changes, and anti-oxidant activity are reviewed. The non-invasive nature of essential oils suggests they have a promising role as adjuncts to conventional therapies for improving the mental health of the aging population.

Antimicrobial activity of essential oil components against Escherichia coli depends on the food components present in a food matrix

Despite numerous studies evaluating the antimicrobial activity of essential oil components (EOCs) against different microorganisms, the effect of the composition of the matrix in which they are applied remains unexplored. Hence, the effect of different food components (i.e., proteins, lipids, carbohydrates, acids, ethanol) on vanillin antimicrobial activity was carried out by assessing the growth of E. coli at different incubation times (0, 1, 4, 8 and 24 h). Based on these outcomes, the food components that most adversely affected vanillin antimicrobial activity were subsequently tested with four other EOCs (i.e., carvacrol, eugenol, geraniol, thymol). The effective concentration of antimicrobials after coming into contact with food components was quantified. The results indicated that bovine serum albumin (BSA), sunflower oil and carbohydrates partially or completely inhibited the antimicrobial efficacy of the tested EOCs, and the inhibition rate depended on the specific EOC-food component combination. Geraniol was notably the most efficient with BSA present. Eugenol performed best with sunflower oil. Carvacrol, eugenol, geraniol and thymol were more effective than vanillin with D-lactose present. This study confirmed that loss of EOCs' effective concentration due to an interaction with food constituents is a significant cause of antimicrobial activity inhibition. These findings underscore the importance of considering matrix composition when selecting antimicrobials to combat a particular strain in real food applications.

Thyme Essential Oil as a Potential Tool Against Common and Re-Emerging Foodborne Pathogens: Biocidal Effect on Bacterial Membrane Permeability

Over the past decade, foodborne diseases have become a significant public health concern, affecting millions of people globally. Major pathogens like Salmonella spp., Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus contaminate food and cause several infections. This study investigates the potential of thyme essential oil (Thy-EO) as a natural antimicrobial agent against most common and re-emerging foodborne bacteria, including S. enterica, Yersinia enterocolitica, and L. monocytogenes. Preliminary tests provided qualitative evidence of Thy-EO's efficacy by evaluating its antibacterial activity through direct contact and vapor phase exposure. Then, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were defined to quantitatively evaluate the bacteriostatic and bactericidal effects of Thy-EO, revealing a strong inhibitory effect against S. enterica, Y. enterocolitica and L. monocytogenes. Additionally, Thy-EO exerted rapid bactericidal kinetics characterized by the disruption of bacterial cell membrane integrity over time. Results highlight Thy-EO's potential as an alternative antimicrobial agent, demonstrating that treatment with Thy-EO significantly and irreversibly affects the growth of the tested foodborne pathogens.

Deciphering the Antimicrobial and Antibiofilm Efficiency of Thyme Essential Oil Encapsulated Zeolitic Imidazole Framework-8 Against Foodborne Pathogens

Food Packaging using antibacterial substances plays a vital role in food industry in controlling contamination caused by food borne pathogens. Stability and pH dependent degradation characteristics of zeolitic imidazole framework-8 (ZIF-8) makes its suitable candidate for biomedical applications. The present study focuses on thyme essential oil (TEO) encapsulated in ZIF-8 to achieve a synergistic antibacterial effect and prolonged drug release, aiming to extend the shelf life of food products. Optical, structural and surface characterizations of TEO encapsulated within ZIF-8 (ZIF-8@TEO) reveals successful incorporation of TEO into ZIF-8 nanoparticles. High drug loading and pH dependent release rate with higher release rate at acidic condition (75%) makes ZIF-8 a promising drug delivery system. ZIF-8@TEO exhibited potent antimicrobial against Staphylococcus aureus, Bacillus subtilius and Pseudomonas aeruginosa, also attenuated the biofilm forming ability of these food borne pathogens. In vitro and in vivo toxicity studies reveal the non-hemolytic and non-toxic nature indicating its biocompatible nature. The results of the study reveal that ZIF-8@TEO nanoconjugate can be used for the development of novel antibacterial nanocomposite-based films for food packaging applications.

Efficacy of foliar application of Chlorella vulgaris extract on chemical composition and biological activities of the essential oil of spearmint (Mentha spicata L.)

The microalgal have an essential role in agriculture, where they are used as biofertilizers. This study aimed to determine the effect of C. vulgaris extract on the chemical composition and biological activities of the Essential Oil (EO) of Mentha spicata. The extract of C. vulgaris was prepared and applied at three different concentrations (50, 75, and 100 %). The EOs of M. spicata were analyzed by gas chromatography-mass spectrometry (GC-MS). The DPPH radical scavenging capability and Ferric Reducing Antioxidant Power (FRAP) techniques were used to assess the antioxidant activity of EOs. The antimicrobial activity of EO was evaluated using the microdilution method against Staphylococcus aureus. The results of GC-MS analysis of EOs identified 46 components, with Carvone (77.5-65.4 %), Limonene (10.31-6.9 %), β-elemene (1.56-0.98 %), and Caryophyllene (10.92-4.77 %) being the predominant constituents. From the highest concentration ranged from 100 % C. vulgaris extract to control respectively, yield and EO content ranged from 171.24 to 131.74 g/m2 and 0.34 to 0.18 %, respectively; Antioxidant activity by DPPH and FRAP methods varied from 1.56 to 4.45 mg/mL, and 405.63 to 68.68 μMFe2+/g, respectively; the Minimum Inhibitory Concentrations (MIC) ranged from 2.4 to 9.6 mg/mL in various treatments. The results indicated that the C. vulgaris extract significantly increased the yield, EO%, Carvone, Limonene, and antioxidant and antibacterial activities compared to the control. The extract of C. vulgaris showed promise as a biofertilizer to enhance the yield, chemical composition, and biological activities of M. spicata.

In Vitro Evaluation of the Antifungal Properties of Bixa orellana L. Essential Oil from the Ecuadorian Amazon Against Candida albicans (ATCC 10231)

Essential oils are investigated due to their biological activity, and the Amazon rainforest, with its rich biodiversity, is a promising source of therapeutic compounds. The aim of this study was to evaluate the essential oil from the leaves of Bixa orellana as an antifungal agent, thus contributing to the search for alternatives that can address the growing resistance to conventional antifungals. B. orellana leaves were collected in the Ecuadorian Amazon and their essential oil was obtained by steam distillation. Their chemical composition was analysed by Gas Chromatography-Mass Spectrometry (GC-MS) and their antifungal activity against Candida albicans was evaluated using the Kirby-Bauer disc diffusion method (ATCC 10231), with nystatin as a positive control. GC-MS analysis revealed the presence of 60 compounds, the main ones being dihydroedulan (27.5%), β-caryophyllene (10.3%), nerolidol (7.21%), trans-β-bergamotene (5.73%), α-santalene (4.94%) and trans-α-bergamotene (4.26%). The essential oil showed moderate antifungal activity against C. albicans, producing an inhibition halo of 13 mm in diameter, which is 48% of the inhibition observed with nystatin (27 mm). The presence of sesquiterpenes, such as β-caryophyllene, known for its membrane-disrupting properties, probably contributes to the observed antifungal effects. The study highlights the potential of B. orellana essential oil as a natural antifungal agent; however, further research is required to evaluate its efficacy against a wider range of pathogenic fungi, its possible synergistic effects with conventional antifungals and its safety and efficacy in vivo.

Evaluation of the Antibacterial and Antioxidant Properties of Chemical Constituents of the Roots of Woodfordia uniflora: An Integrated Approach of Experimental and Computational Study

Woodfordia uniflora is a medicinal plant used for the treatment of malaria, toothache, and stomach problems. The root parts of the plant are also used for healing liver disorders. Silica gel chromatography separation of CH2Cl2/MeOH (1:1) and MeOH extracts of roots of W. uniflora result in the isolation of three compounds, namely, bergenin (1), β-sitosterol (2), and epigallocatechin 3-gallate (3), reported herein for the first time from the plant. The structure of the isolated compounds was elucidated using NMR (1D and 2D) techniques. Disk diffusion and DPPH assay were used to evaluate the antibacterial and antioxidant activities, respectively. Molecular docking was done by the AutoDock Vina 4.2 program. The pharmacokinetics and toxicity profile of compounds were predicted by Swiss ADME and Pro Tox II online servers. GC-MS analysis roots of W. uniflora result in the identification of five compounds, of which palmitic acid (34.9%) was the major constituent. The antibacterial activity result indicated that the oil extract had promising activity against P. aeruginosa, E. coli, S. pyogenes, and S. aureus with IZ of 14.3 ± 0.81, 15.0 ± 0.0, 15.6 ± 0.47, and 17.6 ± 0.47 mm, respectively, at 5 mg/mL, compared to ciprofloxacin (1Z 27-30.0 ± 0.0 mm) at 30 μg/mL. MeOH and CH2Cl2/MeOH (1:1) extract showed inhibition against E. coli (IZ of 13.6 ± 0.47 mm) and P. aeruginosa (IZ of 10.0 ± 0.0 mm), respectively, at 200 mg/mL. Bergenin (1) and β-sitosterol (2) also displayed maximum inhibition of E. coil (IZ of 11.6 ± 0.47) and S. aureus (11.0 ± 0.0 mm), respectively, at 5 mg/mL. The antioxidant activity results showed that CH2Cl2/MeOH (1:1) and MeOH extracts, bergenin (1), and compound 3 displayed potent scavenging DPPH radical with a percentage of inhibition of 76.8 ± 0.12, 77.8 ± 0.08, 71.4 ± 0.08, and 91.2 ± 0.16, respectively, compared to ascorbic acid (93.2% ± 0.04%) at 100 μg/mL. The molecular docking analysis showed that all compounds (1-3) exhibited minimum binding energy toward PDB ID: 1HD2 (-5.2 to -6.3 kcal/mol), compared to ascorbic acid (-5.6 kcal/mol), and toward PDB ID: 1DNU (-8.0 to -10.7 kcal/mol) receptors, compared to ascorbic acid (-5.7 kcal/mol). Toward the PDB ID: 4FM9 receptor, β-sitosterol (2) and compound 3 exhibited the best binding free energy of -9.1 and -9.8 kcal·mol, respectively, compared to vosaroxin (-7.8 kcal/mol). The drug-likeness analysis result indicated that bergenin (1) and β-sitosterol (2) obeyed four and five criteria of Lipinski's rule, respectively, and are more likely to be administered orally. The in silico toxicity analysis showed none of the compounds would be cytotoxic, mutagenic, or hepatotoxic. The in vitro antioxidant and antibacterial results supported by in silico analysis demonstrated that the roots of W. uniflora have the potential to be therapeutic agents for bacterial infections and free radical-inducing diseases.

Phytochemical composition and antimicrobial potential of Stevia rebaudiana Bertoni extract and its topical spray formulation against animal skin pathogens

Background and Aim

The rise of antimicrobial resistance in veterinary medicine is a significant concern, particularly for pathogens responsible for skin infections. Although Stevia rebaudiana Bertoni (stevia) has demonstrated effective antimicrobial properties, there is limited research on its efficacy against animal skin pathogens. This study aimed to identify natural compounds in stevia extract, develop a topical spray formulation, and assess its effectiveness against six common bacterial and fungal pathogens associated with animal skin infections.

Materials and Methods

The aerial parts of stevia plants were extracted using hexane in a Soxhlet apparatus. Total phenolic and flavonoid contents were quantified using colorimetric assays. The volatile oil content was analyzed using gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity of stevia extract against Staphylococcus pseudintermedius, Malassezia pachydermatis, Microsporum canis, Microsporum gypseum, Microsporum gallinae, and Trichophyton mentagrophytes was evaluated using broth microdilution and time-kill tests. Environmental scanning electron microscopy (E-SEM) and leakage studies were conducted to assess the extract's impact on microbial morphology and cell membrane integrity. The antimicrobial efficacy and stability of a topical spray formulation containing stevia extract were evaluated using time-kill and freeze-thaw testing.

Results

The stevia extract yield was 3.59% of the dry plant weight with 259.96 ± 23.66 mg gallic acid equivalent (GAE)/g extract of total phenolics and 247.41 ± 19.92 mg quercetin equivalent (QE)/g extract of total flavonoids. GC-MS analysis identified major volatile components, including N-acetyl-14, 15, 16-trinorlabd-8(17)-en-13-amine (37.70% of peak area), phytol (11.02% of peak area), (-)-spathulenol (9.46% of peak area), n-hexadecanoic acid (8.01% of peak area), and (diphenylphosphinoyloxymethyl) dimethylsilane (7.59% of peak area). The minimum inhibitory concentration of the extract against the tested microorganisms ranged from 0.25 to 128.00 mg/mL. Time-kill kinetics exhibited time- and concentration-dependent germicidal effects. E-SEM and cell leakage analyses indicated that stevia extract compromised microbial cell membrane integrity. A spray formulation containing 10% w/w stevia extract displayed excellent eradication efficacy, achieving a 99.9999% reduction of S. pseudintermedius and a 99.999% reduction of M. pachydermatis and dermatophytes, with good stability after six freeze-thaw cycles.

Conclusion

Stevia extract is an effective antimicrobial against S. pseudintermedius, M. pachydermatis, Mi. canis, Mi. gypseum, Mi. gallinae, and T. mentagrophytes in vitro. Future research will investigate the pharmaceutical properties and toxicity profiles of purified compounds and determine appropriate dosages and clinical efficacy.

Terpenoids as principal bioactive compound of Cissampelos oppositifolia essential oils: enhancing synergistic efficacy with conventional antibiotics

Background

The rise of antibiotic resistance imposes the search for novel antimicrobial strategies as natural products or its combination with antibiotics. This study investigates the synergistic effects of terpenoids from Cissampelos oppositifolia (C. oppositifolia) essential oil in combination with antibiotics against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The aims were to evaluate the antimicrobial efficacy, analyze functional group modifications and assess molecular interaction.

Methods

Essential oil was extracted from C. oppositifolia by hydro-distillation. The EO was analyzed for terpenoid content via Thin Layer Chromatography (TLC). Antimicrobial activity was assessed using the disc diffusion method and Minimum Inhibitory Concentration determinations (MIC) by broth dilution followed by bactericidal essay (Time-killing). FTIR and UV spectroscopy were employed to detect functional group modifications in terpenoid-antibiotic combinations. Molecular docking studies assessed interaction energies between terpenoids and antibiotics.

Results

TLC identified α-pinene, δ-carene, and caryophyllene in the EO. δ-Carene exhibited the highest synergy with antibiotics, showing the lowest MIC of 0.04 mg/mL against S. aureus ATCC-43300 and 0.05 mg/mL against E. coli MTCC-739. Time-kill assays demonstrated that α-pinene, δ-carene, and caryophyllene achieved complete bacterial eradication by 4 hours in combination with amoxicillin against E. coli, and by 2 hours against S. aureus in combination with erythromycin. FTIR analysis revealed peak shifts at 1599, 1774, and 2259 cm-1 for amoxicillin + α-pinene, and new peaks at 1648 and 1287 cm-1 for δ-carene + erythromycin. UV spectra indicated potential complex formations. Docking studies showed δ-carene's strong interaction with erythromycin and amoxicillin, with interaction energies of -96.10 and -87.75 kcal/mol, respectively.

Conclusion

Terpenoids from C. oppositifolia enhance the antimicrobial efficacy of antibiotics. Functional group modifications and complex formations suggest that these interactions may contribute to synergistic effects. These findings support the potential use of terpenoid-antibiotic combinations in overcoming antibiotic resistance and warrant further investigation into their mechanisms of action.

Anticholinesterase and Anti-Inflammatory Activities of the Essential Oils of Sawdust and Resin-Rich Bark from Azorean Cryptomeria japonica (Cupressaceae): In Vitro and In Silico Studies

Alzheimer's disease (AD), a multifactorial neurodegenerative disorder characterized by severe cognitive impairment, affects millions of people worldwide. However, AD therapy remains limited and mainly symptomatic-focused, with acetylcholinesterase (AChE) inhibitors being the major available drugs. Thus, AD is considered by the WHO as a disorder of public health priority. Among several strategies that have been identified to combat AD, the use of natural multi-target drug ligands (MTDLs) appears to be a promising approach. In this context, we previously found that the essential oils (EOs), obtained via hydrodistillation, from Azorean Cryptomeria japonica sawdust (CJS) and resin-rich bark (CJRRB) were able to exert antioxidant activity via different mechanisms of action. Therefore, in the present work, these EOs were screened for their (i) in vitro anti-AChE and anti-butyrylcholinesterase (BChE) activities, evaluated by a modified Ellman's assay; (ii) in vitro anti-inflammatory potential, using the albumin denaturation method; and (iii) toxicity against Artemia salina. The CJRRB-EO exhibited both anti-AChE and anti-BChE activities (IC50: 1935 and 600 µg/mL, respectively), whereas the CJS-EO only displayed anti-BChE activity, but it was 3.77-fold higher than that of the CJRRB-EO. Molecular docking suggested that α-pinene and ferruginol compounds contributed to the anti-AChE and anti-BChE activities, respectively. Moreover, the anti-inflammatory activity of the CJS-EO, the CJRRB-EO, and diclofenac was 51%, 70%, and 59% (at a concentration of only 2.21 μg/mL), respectively, with the latter two presenting comparable activity. Concerning the EOs' potential toxicity, the CJRRB-EO exhibited a lower effect than the CJS-EO (LC50: 313 and 73 µg/mL, respectively). Overall, the EOs from C. japonica biomass residues, chiefly the CJRRB-EO, displayed antioxidant, anticholinesterase, and anti-inflammatory activities in a concentration-dependent manner. These properties demonstrate that these residues may be suitable natural MTDLs for AD complementary therapy when administered through aromatherapy, or, alternatively, could serve as low-cost sources of valuable ingredients, such as α-pinene.

Chemical composition and biological activities of essential oils from Cymbopogon schoenanthus (L.) Spreng.: a Saharan plant from Ghardaïa region (Algeria)

The essential oils (EOs) of Cymbopogon schoenanthus (L.) Spreng. collected from Ghardaïa Province were analyzed for their chemical composition by GC-MS analysis. The results showed fifty-one identified compounds representing 94.34% of the whole EOs, with β-eudesmol (11.35%) and α-elemol (10.84%) as major compounds. The TAC, DPPH, and FRAP antioxidant activities of the EOs were moderate, while an important inhibition of 63.54 ± 2.41% was obtained for the β-carotene bleaching assay. The results of the antibacterial activity show that gentamicin had an inhibition zone of 21.66 ± 0.57 mm while Bacillus cereus was the most sensitive species (inhibition zone of 20.75 ± 0.50 mm). The wound-healing activity results showed contraction percentages on the 20th day of 99.35 ± 0.12%, which was similar to the positive control 1% allantoin (98.33 ± 0.17%). Our results show that C. schoenanthus is a source of many bioactive compounds with well-known antioxidant, antibacterial and wound-healing properties.

Assessment of physicochemical characteristics and bioactive compounds of the essential oil of wild herbs aromatic from Andean region of South Perú

Essential oils are a subject of study due to the heterogeneity of their components, which vary according to the genus and species of the plant material. The objective of this study was the physicochemical characterization and bioactive components of the essential oil (EO) extracted from wild punamuña (Satureja Boliviana) and runtuhuayra (Clinopodium Weberbaueri (Mansf.) Govaerts) herbs from high Andean areas of southern Peru. The extraction of the EO from both species was carried out using the steam distillation technique, the density characterization using gravimetric methods and the acidity, peroxide index and refraction by analytical methods recommended by the Norma Tecnica Peruana (NTP). The bioactive compounds were quantified using gas chromatography coupled to a mass spectrometry detector (GC-MS). A better EO performance was obtained from punañuna 0.38% (w/w) compared to runtuhuayra 0.28% (w/w); In both samples, the density and refractive index were similar values (0.93-0.94) g/mL and (1.528-1.520) (p>0.05) respectively; However, the acid and peroxide index showed a significant difference between the samples studied (p<0.05). 37 bioactive compounds synthesized as secondary metabolites in Satureja Boliviana EO were identified, with the majority being monoterpenes (62%) highlighted by menthone, L-menthone, pulegone and 3-cyclohexen-1-one. 2-isopropyl-5-methyl, linalool, α-cadinene and α-cadinol; Meanwhile, in the EO of Clinopodium Weberbaueri, 28 compounds were detected and quantified, in which monoterpenes predominate (61%) made up of pulegone (45.67%); isomenthol (13.85%), menthone (6.05%), carvacrol (5.39%), and also D-limonene; o-cymene; 3-octanol; β-pinene and α-terpineol successively. This characterization of the EO of the aforementioned samples reveals recent a new additive or ingredient alternative for the industry due to its biological value associated with antioxidant, antimicrobial, anti-inflammatory activities and psychotherapeutics.

Investigating the Synergistic Effects of Carvacrol and Citral-Edible Polysaccharide-Based Nanoemulgels on Shelf Life Extension of Chalkidiki Green Table Olives

Modern bioeconomy and sustainability demands lead food technology in the development of novel biobased edible food preservatives. Herein, the development and characterization of novel polysaccharide (xanthan gum and kappa-carrageenan)-based nanoemulgels (NGs) enhanced with essential oil derivatives; pure citral (CT); pure carvacrol (CV); and various CT:CV ratios (25:75, 50:50, and 75:25) are presented. The obtained NGs are applied as active edible coatings for extending the shelf life of Protected Designation of Origin (PDO) green table olives of Chalkidiki. The zeta potential demonstrated the high stability of the treatments, while light scattering measurement and scanning electron microscopy images confirmed the <100 nm droplet size. EC50 indicated high antioxidant activity for all the tested samples. The fractional inhibitory concentration (FIC) confirmed the synergistic effect of NG with a CT:CV ratio at 50:50 against Staphylococcus aureus and at CT:CV ratios 25:75 and 75:25 against E. coli O157:H7. NG coatings with CT:CV ratios at 50:50 and at 25:75 effectively controlled the weight loss at 0.5%, maintained stable pH levels, and preserved the visual quality of green olives on day 21. The synergistic effect between CT and CV was confirmed as they reduced the spoilage microorganisms of yeasts and molds by 2-log [CFU/g] compared to the control and almost 1 log [CFU/g] difference from pure CT and CV-based NGs without affecting the growth of beneficial lactic acid bacteria crucial for fermentation. NGs with CT:CV ratios at 50:50 and at 25:75 demonstrated superior effectiveness in preventing discoloration and maintaining the main sensory attributes. Overall, shelf life extension was achieved in 21 compared to only 7 of the uncoated ones. Finally, this study demonstrates the potential of polysaccharide-based NGs in mixtures of CT and CV for the shelf life extension of fermented food products.

Antibacterial Effects of Essential Oils on P. aeruginosa, Methicillin-Resistant S. aureus, and Staphylococcus spp. Isolated from Dog Wounds

Background: Essential oils exhibit several biological activities such as antimicrobial, antioxidant, proliferative, and anti-inflammatory. This study was aimed at investigating the antimicrobial effects and cytotoxic activities of niaouli, palmarosa, and clove essential oils. Methods: Content analyses of these essential oils were carried out by gas chromatography-mass spectrometry. The antibacterial activity was screened against methicillin-resistant S. aureus ATCC 43300, P. aeruginosa ATCC 27853, P. aeruginosa PAO1, S. aureus ATCC 25923, and 44 isolates (22 P. aeruginosa isolates, 4 S. aureus isolates, and 18 Staphylococcus spp. isolates) obtained from dogs with previous wound infections who were included in the current study. The antimicrobial effects of essential oils were investigated using disk diffusion and minimum inhibition/bactericidal concentration methods. Additionally, the antibiofilm, protease, elastase, and gelatinase activities of the essential oils were evaluated. Different concentrations of each essential oil ranging from 10 to 1000 µg/mL were also analyzed in terms of cell viability by WST-8 assay in primary canine fibroblast cells. Results: The fibroblast cell viabilities of palmarosa, niaouli, and clove oils at a 1000 µg/mL concentration were 75.4%, 96.39%, and 75.34%, respectively. All the EOs were found to have bactericidal effects with MBCs/MICs of 0.015 to 0.5 µL/mL against P. aeruginosa, Staphylococcus isolates (p < 0.001). Palmarosa was found to have the largest inhibition zone diameter (20.5 ± 6.6, 16.4 ± 2.3) compared to other essential oils in the disk diffusion test against Staphylococcus spp. and P. aeruginosa (p < 0.001). But none of the EOs reduced protease, elastase, and gelatinase activities, which are some of the virulence properties of the tested bacteria. Conclusions: These results showed that palmarosa, niaouli, and clove essential oils act as potential antibacterial agents for dogs against P. aeruginosa, methicillin-resistant S. aureus, and Staphylococcus spp., without damaging the skin.

Integration of CRISPR/Cas9 with multi-omics technologies to engineer secondary metabolite productions in medicinal plant: Challenges and Prospects

Plants acts as living chemical factories that may create a large variety of secondary metabolites, most of which are used in pharmaceutical products. The production of these secondary metabolites is often much lower. Moreover, the primary constraint after discovering potential metabolites is the capacity to manufacture sufficiently for use in industrial and therapeutic contexts. The development of omics technology has brought revolutionary discoveries in various scientific fields, including transcriptomics, metabolomics, and genome sequencing. The metabolic pathways leading to the utilization of new secondary metabolites in the pharmaceutical industry can be identified with the use of these technologies. Genome editing (GEd) is a versatile technology primarily used for site-directed DNA insertions, deletions, replacements, base editing, and activation/repression at the targeted locus. Utilizing GEd techniques such as clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 (CRISPR-associated protein 9), metabolic pathways engineered to synthesize bioactive metabolites optimally. This article will briefly discuss omics and CRISPR/Cas9-based methods to improve secondary metabolite production in medicinal plants.

Comparing diverse extraction methodologies to infer the performance of 1,8-cineole extraction from Eucalyptus cinerea: process optimization, kinetics, and interaction mechanisms

Eucalyptus oil is highly valued for its anti-inflammatory, antiviral, and antibacterial qualities. Research has shown that it is a powerful combatant against cancer cells, making it an extremely interesting area of research. For the first time, the present study proposes to extract 1,8-cineole from Eucalyptus cinerea leaves using different extraction methodologies, namely, hydro-distillation (HD), Soxhlet (SE), ultrasonication (UE), and microwave (ME) extraction techniques. In conventional extraction, HD yielded a maximum of 72.85% 1,8-cineole using a minimum solid-solvent ratio of 1 : 10 g mL-1 within 3 h compared to SE. The first-order kinetic equation was applied in the HD experimental dataset to understand the extraction mechanism. In modern extraction technology, ME achieved the highest yield of 1,8-cineole (95.62%) at the optimal solid-solvent ratio of 2 g mL-1, extraction time of 4.5 min, and irradiation power of 640 W using the response surface methodology (RSM). Furthermore, the kinetic analysis of UE was investigated using three different empirical models. The chemical components of the essential oil extracted using each extraction method were identified as oxygenated monoterpenes, sesquiterpenes, and oxygenated sesquiterpenes using gas chromatography. Following extraction using various techniques, the morphology of spent leaves lost its distinct texture, their oil glands were entirely distorted, and their vascular bundles could still be identified. It was observed that the hydrogen bond interaction between the solvent molecule and 1,8-cineole-like value-added components played a role in the extraction. Among the investigated techniques, the solvent-free ME method is the most environmentally acceptable method and could effectively extract essential oil from E. cinerea leaves.

Synthesis and Thermal Properties of Bio-Based Janus Ring Siloxanes Incorporating Terpenes and Terpenoids

A mild and highly selective hydrosilylation method was employed to synthesize five novel well-defined Janus ring siloxanes bearing terpenes and terpenoids, which are the main bioactive components of essential oils. The characterization of these new bio-sourced molecular materials, derived from hydrosilyl-substituted all-cis-cyclotetrasiloxane, was conducted through comprehensive analyses using multinuclear NMR, infrared spectroscopy, elemental analysis, and mass spectroscopy. The thermal stability of the newly synthesized Janus rings was investigated, and the siloxane skeleton was shown to confer an enhanced thermal stability compared with free terpenes and terpenoids.

Investigation of physicochemical and antibacterial properties of dill (Anethum graveolens L.) microencapsulated essential oil using fluidized bed method

The present study delves into the encapsulation of dill essential oil utilizing the fluidized bed coating methodology. The investigation focused on the impact of essential oil concentration and the application of maltodextrin and arabic gum as the primary and secondary coating agents. The dominant compounds in the dill essential oil were identified as limonene (32.32%), carvone (35.43%), and cis-dihydrocarvone (5.43%). The antimicrobial potency of the dill essential oil was evaluated, demonstrating notable inhibition against Streptococcus mutans with inhibition zone diameters ranging from 5.4 mm to 16 mm for concentrations between 250 μg/mL and 2000 μg/mL. For Streptococcus sobrinus, the inhibition zones measured from 6.6 mm to 18 mm across the same concentration gradient. An increase in maltodextrin concentration was associated with a decrease in moisture content, bulk density, and tapped density, while it improved microencapsulation efficiency and loading capacity. In contrast, a higher concentration of arabic gum increased moisture content, loading capacity, and encapsulation efficiency, but reduced bulk density and tapped density. Elevating the essential oil concentration increased all physicochemical properties of the microcapsules, except for tapped density. The optimal conditions for microencapsulation involve using a 2000 ppm concentration of dill essential oil with 75% maltodextrin and 0.1% arabic gum as carrier agents. Scanning electron microscopy images indicated that the microcapsule particles were nearly spherical with a smooth, intact surface. The release rate of phenolic compounds in a simulated saliva environment reached its maximum at 98.32% after 20 min, showcasing an efficient release profile.

Vapor-Phase Essential Oils as Antifungal Agents against Penicillium olsonii Causing Postharvest Cherry Tomato Rot

Recent reports of P. olsonii causing postharvest rot of cherry tomatoes emphasize the need for effective strategies to prolong fruit shelf life. This study is the first to explore the use of essential oils (EOs), recognized for their antimicrobial properties, as a potential method to prevent postharvest losses from P. olsonii. Antifungal activity was tested for ten EOs at a concentration of 625 μL/L using the vapor diffusion method. Thyme, wild thyme, savory, oregano, and marjoram completely inhibited fungal growth over 14 days. Thyme EO, at a minimum inhibitory concentration (MIC) of 250 μL/L, fully inhibited all strains, while oregano, wild thyme, and savory were effective at 500 μL/L. Marjoram EO showed weaker activity. The lowest IC90 values, ranging from 35.72 to 162.72 μL/L, were estimated for thyme and oregano. In cherry tomatoes, oregano EO completely halted P. olsonii growth at 250 μL/L; thyme was effective for seven days; wild thyme and savory for two days. Thyme EO prevented P. olsonii spore germination at 500 μL/L for seven days, though germination occurred at half that concentration. The IC90 values varied between 256.2 and 138.7 μL/L depending on the strain. The vapor phase of EOs at 125 μL/L influenced the sensory characteristics of cherry tomatoes; however, for thyme and oregano, this effect was not negative due to their culinary association with tomato flavor. The selected EOs could be used to control and prevent postharvest fruit losses, but further research is needed to optimize their application.

Methods for Determination of Antimicrobial Activity of Essential Oils In Vitro-A Review

Essential oils (EOs) have been gaining popularity in the past decades among researchers due to their potential to replace conventional chemicals used in the fight against pests, pathogenic and spoilage microbes, and oxidation processes. EOs are complex mixtures with many chemical components, the content of which depends on many factors-not just the plant genus, species, or subspecies, but also chemotype, locality, climatic conditions, phase of vegetation, method of extraction, and others. Due to this fact, there is still much to study, with antimicrobial effect being one of the key properties of EOs. There are many methods that have been frequently used by researchers for in vitro evaluation; however, although the research has been going on for decades, an internationally accepted standard is still missing. Most of methods are based on time-proven standards used for the testing of antibiotics. Due to the specific properties of EOs and their components, such as volatility and hydrophobicity, many modifications of these standard procedures have been adopted. The aim of this review is to describe the most common methods and their modifications for the testing of antimicrobial properties of EOs and to point out the most controversial variables which can potentially affect results of the assays.

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.

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.

Hydroxypropyl Cellulose Hydrogel Containing Origanum vulgare ssp. hirtum Essential-Oil-Loaded Polymeric Micelles for Enhanced Treatment of Melanoma

Origanum vulgare ssp. hirtum essential oil (OEO) is a natural oil with high therapeutic potential. For some applications, however, the development of novel formulations is still needed to improve the bioavailability and stability of OEO. In this study, we describe the fabrication of an original nanocomposite hydroxypropyl cellulose (HPC) physical hydrogel, containing OEO-loaded polymeric micelles, for topical delivery. The concentration of the main active compounds of OEO-carvacol and thymol-was determined using gas chromatography (GC) analysis. OEO was first encapsulated into Pluronic F127 micelles, and then embedded into HPC gel. Micellar and gel formulations of pure polymers and OEO-containing systems were characterized by dynamic light scattering (DLS) and rheology measurements, respectively. Selected formulations were evaluated for cytotoxicity and antiproliferative activity. The hydrogel formulation of HPC with micellar OEO (8% HPC, 2% F127, 1% OEO) exhibited sustained release of the oil and selectivity towards SH-4 tumor cells (an in vitro model of melanoma).

Nail Lacquer Containing Origanum vulgare and Rosmarinus officinalis Essential Oils and Biogenic Silver Nanoparticles for Onychomycosis: Development, Characterization, and Evaluation of Antifungal Efficacy

Onychomycosis is a common fungal nail infection for which new antifungals are needed to overcome antimicrobial resistance and the limitations of conventional treatments. This study reports the development of antifungal nail lacquers containing oregano essential oil (OEO), rosemary essential oil (REO), and biogenic silver nanoparticles (bioAgNPs). The formulations (F) were tested against dermatophytes using agar diffusion, ex vivo nail infection, and scanning electron microscopy techniques. They were evaluated for their pharmacotechnical characteristics and by FTIR-PAS to assess permeation across the nail. F-OEO and F-OEO/bioAgNPs were promising candidates for the final nail lacquer formulation, as they permeated through the nail and showed antifungal efficacy against dermatophytes-contaminated nails after 5 days of treatment. Treated nails exhibited decreased hyphae and spores compared to the untreated control; the hyphae were atypically flattened, indicating loss of cytoplasmic content due to damage to the cytoplasmic membrane. The formulations were stable after centrifugation and thermal stress, maintaining organoleptic and physicochemical characteristics. Both F-OEO and F-OEO/bioAgNPs had pH compatible with the nail and drying times (59-90 s) within the reference for nail lacquer. For the first time, OEO and bioAgNPs were incorporated into nail lacquer, resulting in a natural and nanotechnological product for onychomycosis that could combat microbial resistance.

Toxicity and enzymatic mechanism of Citrus spp. essential oils and major constituents on Haemaphysalis longicornis (Acari: Ixodidae) and non-target Harmonia axyridis (Coleoptera: Coccinellidae)

Plant essential oils (EOs)-based acaricides have been recognized as environmentally-friendly alternatives to synthetic acaricides because of their low toxicity against non-target species. Despite this, there are knowledge gaps regarding the toxicity mechanisms of plant EOs against non-target species. Here, the toxicology and enzymatic mechanism of Citrus reticulata and Citrus lemon EOs were evaluated against the vector pest, Haemaphysalis longicornis, and non-target ladybird beetle, Harmonia axyridis. Both EOs were mainly composed of d-Limonene, followed by β-Myrcene and γ-Terpinene in C. reticulata, and (-)-β-Pinene and γ-Terpinene in C. lemon. Citrus reticulata and C. lemon EOs were toxic to Hae. longicornis, with 50 % lethal concentration (LC50) values estimated at 0.43 and 0.98 μL/mL via nymphal immersion test, and 42.52 and 46.38 μL/mL via spray application, respectively. Among the constituents tested, β-Myrcene was the most effective, with LC50 values of 0.17 and 47.87 μL/mL via immersion and spray treatment, respectively. A significant mortality of non-target Har. axyridis was found when treated by the EOs at concentrations two times greater than LC50 estimated against H. longicornis. The biochemical assay revealed that the EOs induced changes in the antioxidant enzyme activity of superoxide dismutases, catalase, and glutathione peroxidase in Hae. longicornis and Har. axyridis. The results demonstrated the acaricidal potential of citrus EOs and their major constituents for tick control, revealed the risk of the EOs to non-target species, and provided relevant insights into the mechanisms underlying their toxicity.

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.