Mechanism Of Essential Oil Research Articles

The protective effects and mechanisms of essential oil from Chimonanthus nitens Oliv. leaves in allergic rhinitis based on the NF-κB and T-bet/GATA-3 signaling pathways

Ethnopharmacological relevancePreliminary studies showed that Shanlameiye granules are derived from Chimonanthus nitens Oliv. Leaves ameliorate inflammatory responses in mice with Allergic Rhinitis (AR). The essential oil from Chimonanthus nitens Oliv. Leaves (CLO) have been identified as the key active substances in these granules. However, whether CLO constitutes the primary mechanism for the mitigation of AR-related inflammation by these granules has not yet been investigated. Aim of the studyThis experiment was to validate the effects and mechanism of CLO on inflammatory responses in RAW264.7 cells and AR rat model. Materials and methodsAn inflammatory model was induced in RAW264.7 cells by Lipopolysaccharide (LPS) & Interferon-gamma (IFN-γ) stimulation. AR rat model was established using both systemic and local challenges with Ovalbumin (OVA). ResultsIn cell experiments, CLO obviously decreased the secretion of cytokines and inhibited the NF-κB signaling pathway activation. In animal experiments, CLO decreased the number of eosinophils in the blood and lowered the levels of cytokines in nasal lavage fluid (NALF). Additionally, CLO inhibited the expression of STAT6, GATA-3, and p-p65, while increasing the expression of STAT4 and T-bet in the nasal mucosa. ConclusionIn AR rat model, CLO may play an anti-inflammatory role in AR rat model by regulating NF-κB and T-bet/GATA-3 signaling pathways.

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.

Analysis of Pharmacological Activities and Mechanisms of Essential Oil in Leaves of C. grandis 'Tomentosa' by GC-MS/MS and Network Pharmacology.

Citrus grandis 'Tomentosa,' a fruit epicarp of C. grandis 'Tomentosa' or C. grandis (L.) Osbeck is widely used in health food and medicine. Based on our survey results, there are also rich essential oils with bioactivities in leaves, but the chemical compounds in this part and relevant pharmacological activities have never been studied systematically. Therefore, this study was to preliminarily decipher the pharmacological activities and mechanisms of the essential oil in leaves of C. grandis 'Tomentosa' by an integrated network pharmacology approach. Essential oil compositions from leaves ofC. grandis 'Tomentosa' were identified using GC-MS/MS. And then, the targets of these oil compositions were predicted and screened from TCMSP, SwissTargetPrediction, STITCH and SEA databases. STRING database was used to construct the protein-protein interaction networks, and the eligible protein targets were input into WebGestalt 2019 to carry out GO enrichment and KEGG pathway enrichment analysis. Based on the potential targets, disease enrichment information was obtained by TTD databases. Cytoscape software was used to construct the component-target-disease network diagrams. Finally, 61 essential oil chemical components were identified by GC-MS/MS, which correspond to 679 potential targets. Biological function analysis showed 12, 19, and 12 GO entries related to biological processes, cell components and molecular functions, respectively. 43 KEGG pathways were identified, of which the most significant categories were terpenoid backbone biosynthesis, TNF signaling pathway and leishmaniasis. The component-target-disease network diagram revealed that the essential oil compositions in leaves of C. grandis 'Tomentosa' could treat tumors, immune diseases, neurodegenerative diseases and respiratory diseases, which were highly related to CHRM1, PTGS2, CASP3, MAP2K1 and CDC25B. This study may provide new insight into C. grandis 'Tomentosa' or C. grandis (L.) Osbeck and may provide useful information for future utilization and development.

Advances in the Role and Mechanisms of Essential Oils and Plant Extracts as Natural Preservatives to Extend the Postharvest Shelf Life of Edible Mushrooms

China has a large variety of edible mushrooms and ranks first in the world in terms of production and variety. Nevertheless, due to their high moisture content and rapid respiration rate, they experience constant quality deterioration, browning of color, loss of moisture, changes in texture, increases in microbial populations, and loss of nutrition and flavor during postharvest storage. Therefore, this paper reviews the effects of essential oils and plant extracts on the preservation of edible mushrooms and summarizes their mechanisms of action to better understand their effects during the storage of mushrooms. The quality degradation process of edible mushrooms is complex and influenced by internal and external factors. Essential oils and plant extracts are considered environmentally friendly preservation methods for better postharvest quality. This review aims to provide a reference for the development of new green and safe preservation and provides research directions for the postharvest processing and product development of edible mushrooms.

Effective constituents of essential oil from Gleditsiae Fructus Abnormalis and anti-cerebral ischemia/reperfusion injury mechanism: based on GC-MS, network pharmacology, and experimental verification

Based on GC-MS and network pharmacology, the active constituents, potential targets, and mechanism of essential oil from Gleditsiae Fructus Abnormalis(EOGFA) against cerebral ischemia/reperfusion(I/R) injury were explored, and the effective constituents were verified by experiment. To be specific, GC-MS was used identify the constituents of the volatile oil. Secondly, the targets of the constituents and disease were predicted by network pharmacology, and the drug-constituent-target network was constructed, followed by Gene Ontology(GO) term enrichment and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment of the core targets. Molecular docking was performed to investigate the binding affinity between the active constituents and the targets. Finally, SD rats were used for experimental verification. The I/R injury model was established, and the neurological behavior score, infarct volume, and pathological morphology of brain tissue were measured in each group. The content of interleukin-1β(IL-1β), interleukin-6(IL-6), and tumor necrosis factor-alpha(TNF-α) was determined by enzyme-linked immunosorbent assay(ELISA), and the protein expression of vascular endothelial growth factor(VEGF) by Western blot. A total of 22 active constituents and 17 core targets were screened out. The core targets were involved in 56 GO terms and the major KEGG pathways of TNF signaling pathway, VEGF signaling pathway, and sphingolipid signaling pathway. Molecular docking showed that the active constituents had high affinity to the targets. The results of animal experiment suggested that EOGFA can alleviate the neurological impairment, decrease the cerebral infarct volume and the content of IL-1β, IL-6 and TNF-α, and down-regulate the expression of VEGF. The experiment verified the part results of network pharmacology. This study reflects the multi-component, multi-target, and multi-pathway characteristics of EOGFA. The mechanism of its active constituents is related to TNF and VEGF pathways, which provides a new direction for in-depth research on and secondary development of Gleditsiae Fructus Abnormalis.

Mechanism of essential oil from Schizonepeta tenuifolia in treatment of depression based on network pharmacology and experimental verification

This paper aimed to explore the antidepressant effect of the essential oil from Schizonepeta tenuifolia Briq.(EOST) on the treatment of depression and its mechanism by using a combination of network pharmacology and the mouse model of lipopolysaccharide(LPS)-induced depression. The chemical components in EOST were identified using gas chromatography-mass spectrometer(GC-MS), and 12 active components were selected as the study objects. The targets related to EOST were obtained by Traditional Chinese Medicines Systems Pharmacology(TCMSP) and SwissTargetPrediction database. The targets related to depression were screened out through GeneCards, Therapeutic Target Database(TTD), and Online Mendelian Inheritance in Man(OMIM) database. The Venny 2.1 was applied to screen out the common targets of EOST and depression. The targets were imported into Cytoscape 3.7.2 to generate "drug-active component-diease-target" network diagram. The protein-protein interaction(PPI) network was constructed using STRING 11.5 database and Cytoscape 3.7.2, and the core targets were screened out. DAVID 6.8 database was used for Gene Ontology(GO) func-tional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis, and subsequently the enrichment results were visualized through the bioinformatics platform. The mouse model of depression was induced by intraperitoneally injecting with LPS in mice. Before modeling, mice were administrated orally with EOST. The antidepressant effect of EOST was evalua-ted by tail suspension test(TST), forced swimming test(FST), and novelty suppressed feeding test(NSFT) after modeling. The content of interleukin(IL)-1β was determined by enzyme-linked immunosorbent assay(ELISA), and the protein expression levels of IL-1β and pro IL-1β in the hippocampus were determined by Western blot. There were 12 main components and 179 targets in EOAT, of which, 116 targets were related to depression, mainly involved in neuroactive ligand-receptor interaction, calcium signaling pathway, and cyclic adenosine monophosphate(cAMP) signaling pathway. Biological processes such as synaptic signal transduction, G-protein coupled receptor signaling pathway, and chemical synaptic transmission were involved. Molecular functions such as neurotransmitter receptor activity, RNA polymerase Ⅱ transcription factor activity, and heme binding were involved. In mice experiments, the results showed that EOST at 100 mg·kg~(-1) and 50 mg·kg~(-1) significantly shortened the immobility time in TST and FST as well as the feeding latency in NSFT compared with the model group, decreased the levels of serum IL-1β and NO, and reduced the protein expression levels of IL-1β and pro IL-1β in the hippocampus. In conclusion, EOST shows a good antidepressant effect in a multi-component, multi-target, and multi-pathway manner. The mechanism may be attributed to the fact that EOST can down-regulate the protein expression levels of IL-1β and pro IL-1β, decrease the release of inflammatory factors, and reduce neuroinflammation response.

Essential oils for the treatment of skin anomalies: Scope and potential

• Skin diseases contribute significantly to worldwide morbidity and mortality. • With increasing prevalence of COVID-19, skin complications are rising in number. • Essential oils contain ingredients which can be used for the prevention/treatment of skin disorders. • The mechanism of essential oils in the treatment of major skin disorders such as eczema, atopic dermatitis, acne, psoriasis, skin cancer, fungal infections and so on, have been discussed. • This knowledge will help the formulation scientists and clinicians in designing a suitable delivery system for the treatment of skin anomalies. Skin diseases contribute significantly to worldwide morbidity and mortality. It is the most common of all human diseases which can affect people of any age group. Most importantly, it is seen that the COVID-19 pandemic have further detrimentally contributed to dermatological manifestations. Due to the enormous socioeconomic burden created by skin disorders, the dermatological treatments have been added in the WHO List of Essential Medicines. Some of the major predominant diseases are acne, psoriasis, eczema, fungal infections and skin carcinoma. As a matter of fact, focus on treatment of skin diseases should be arguably considered as a matter of global urgency. Although treatments are available, they face numerous challenges which limit patient acceptability. Essential oils have a long history of pharmacological use; however their role in the treatment of dermatological disorders is vague. Therefore, in this review, the potential and mechanism of different essential oils obtained from various sources in the treatment of major dermal disorders has been summarized. This will help the formulation scientists and the clinicians to develop suitable formulation strategies for the prevention and cure of skin diseases.

Alleviating effects of essential oil from Artemisia vulgaris on enteritis in zebrafish via modulating oxidative stress and inflammatory response

Artemisia vulgaris (A. vulgaris) is a traditional Chinese medicine widely distributed in China and contains many bioactive compounds with pharmacological effects. However, the anti-inflammatory effects and mechanism of essential oil from A. vulgaris on enteritis in fish are still unclear. In this study, in order to elucidate the underlying mechanism of essential oil from A. vulgaris on zebrafish enteritis, zebrafish were used for establishing animal models to observe the histopathological changes of intestines, determine the activities of immune-related enzymes and oxidative stress indicators, and the mRNA expression of genes in MyD88/TRAF6/NF-KB signaling pathways. The results showed that different doses of A. vulgaris essential oil could effectively alleviate zebrafish enteritis in a dose- and time-dependent manner by improving the intestinal histopathological damage, decreasing the intestinal oxidative stress, repairing the intestinal immune ability, changing the expression levels of IL-1β, IL-10 and genes in MyD88/TRAF6/NF-κB pathway. In addition, co-treatment with oxazolone and MyD88 inhibitor could alleviate the morphological damage, the induction of oxidative stress, and the levels of immune-related enzymes and the mRNA expression of genes in MyD88/TRAF6/NF-κB signaling pathway. Moreover, essential oil from A. vulgaris had more significantly therapeutic effects on enteritis of male zebrafish than that of female zebrafish. This result will clarify the therapeutic effect and anti-inflammatory mechanism of essential oil from A. vulgaris on zebrafish enteritis, and provide a theoretical basis for further research on the rationality of A. vulgaris to replace feed antibiotics.

Antibacterial activity and mechanism of essential oils in combination with medium-chain fatty acids against predominant bovine mastitis pathogens.

Bovine mastitis has become a significant economic importance for the dairy industry. Concerns regarding poor milk quality and emergence of bacterial resistance have necessitated to develop an alternative therapeutic approach to antibiotics for the treatment of mastitis. Saturated medium-chain fatty acids (MCFAs) and essential oils (EOs) are known natural antimicrobials, but their combined effect has not been investigated extensively. The objective of the present investigation was to examine the bactericidal effect of various combined treatments of eight EOs and three saturated MCFAs to inactivate predominant mastitis pathogens, including Staphylococcus aureus ATCC 29213; Escherichia coli ATCC 25922; Klebsiella pneumoniae ATCC 27736 and Streptococcus agalactiae ATCC 27956. The minimum inhibitory concentration (MIC) values confirmed that all the tested pathogens were variably susceptible to both EOs and saturated MCFAs. Among essential oils, carvacrol (CAR), trans-cinnamaldehyde (TC) and thymol (TM) showed the highest inhibitory activity at concentration 0·38-1·32 mg/mL. Carvacrol exhibited effective additive antibacterial activity in combined treatment with octanoic acid (OA) in terms of its fractional inhibitory index (0·63-0·88) and time-kill effect in reducing about 6 log CFU/mL bacterial cells in less than 5 min. The effort was also made to elucidate the mechanism of antibacterial action of CAR and OA against selected mastitis pathogens by observing changes in cell microstructure, permeability and integrity of cell membrane and their membrane potential. After adding CAR and OA at MIC level, there were obvious changes in cell morphology, leakage of small electrolytes and macromolecules at the initial few hours of treatment i.e. within 1-2 h were observed. Our results indicated that CAR and OA could be evaluated as alternatives or adjuncts to antibiotics as intramammary infusion or topical application to treat bovine mastitis, significantly improving the microbiological safety of milk.

Використання ароматерапії для лікування та профілактики гострих респіраторних захворювань у дітей

У статті висвітлено дані про історію ароматерапії, питання механізмів впливу на організм людини ефірних олій, особливості їх терапевтичного ефекту. Наведено основні принципи використання ефірних олій, особливості дозування та режими застосування ефірних олій у дітей. Описано способи застосування ефірних олій у профілактиці і лікуванні гострих респіраторних інфекцій у дітей.

Efficacy and mechanism of essential oil from Abies holophylla leaf on airway inflammation in asthma: Network pharmacology and in vivo study

BackgroundAsthma is one of the most common chronic inflammatory diseases of the airways. Essential oil from Abies holophylla leaf (EOA) has been reported to have anti-inflammatory property. This study aimed to predict the inhibitory effect of EOA against asthma by network analysis and to confirm the underlying mechanism of EOA on airway inflammation. Purpose and study designThe effects and underlying mechanisms of EOA on asthma were investigated by in silico network pharmacology and an experimental in vivo study. MethodsTo define the effectiveness of EOA on asthma, the network pharmacology was constructed using major components of EOA. EOA (0.0003 and, 0.03 v/v%) was aerosolized by nebulizer 3 times a week for 5 min for 7 weeks. After 3 weeks of treating the mice with EOA, asthma was induced by sensitizing them with ovalbumin (OVA) and PM10. The effects of EOA on the IL-17 related signaling pathway was confirmed using an asthmatic model. ResultsThe network analysis showed that EOA is highly associated with the IL-17-related signaling pathway. EOA inhibited respiratory epithelium hyperplasia, collagen deposition and goblet cell activation in the lung and trachea tissues. In addition, EOA reduced the number of eosinophils, lymphocytes and macrophages in BALF. Furthermore, in the asthmatic model of mice, we showed that EOA inhibited IL-17-related cytokines, increased Treg-related cytokines and decreased the TRAF6 and MAPK and, suppressed the nuclear transcriptional activities of NF-kB. ConclusionsThe network pharmacology and in vivo study indicated that EOA may have an inhibitory effect on airway inflammation in asthma exposure through the IL-17-related signaling pathway.

Research Progress on Inhibition Mechanism and Application Mode of Essential Oil to Aspergillus flavus

Aspergillus flavus is a kind of common fungus. The aflatoxin produced by Aspergillus flavus threatens the lives and health of humans and animals. In recent years, aflatoxin poisoned incidents have occurred frequently. As a natural active substance, essential oil exerts strong inhibitory effect on Aspergillus flavus, which mechanism and application mode are still widely concerned in the world. This article mainly summarizes the dangers of Aspergillus flavus, the inhibitory effect and mechanism of essential oils on Aspergillus flavus, and the practising that essential oils inhibit Aspergillus flavus lately, for providing a theoretical basis about the implement of essential oils in inhibiting Aspergillus flavus.

Therapeutic Effect and Mechanisms of Essential Oils in Mood Disorders: Interaction between the Nervous and Respiratory Systems.

Essential oils (EOs) are extracted from plants and contain active components with therapeutic effects. Evidence shows that various types of EOs have a wide range of health benefits. In our previous studies, the potential of lavender EO for prevention and even treatment of depression and anxiety symptoms was demonstrated. The favourable outcomes may be due to multiple mechanisms, including the regulation of monoamine level, the induction of neurotrophic factor expression, the regulation of the endocrine system and the promotion of neurogenesis. The molecules of EOs may reach the brain and exert an effect through two distinctive pathways, namely, the olfactory system and the respiratory system. After inhalation, the molecules of the EOs would either act directly on the olfactory mucosa or pass into the respiratory tract. These two delivery pathways suggest different underlying mechanisms of action. Different sets of responses would be triggered, such as increased neurogenesis, regulation of hormonal levels, activation of different brain regions, and alteration in blood biochemistry, which would ultimately affect both mood and emotion. In this review, we will discuss the clinical effects of EOs on mood regulation and emotional disturbances as well as the cellular and molecular mechanisms of action. Emphasis will be put on the interaction between the respiratory and central nervous system and the involved potential mechanisms. Further evidence is needed to support the use of EOs in the clinical treatment of mood disturbances. Exploration of the underlying mechanisms may provide insight into the future therapeutic use of EO components treatment of psychiatric and physical symptoms.

Effect and mechanism of essential oil from Zanthoxylum bungeanum in microemulsion gel preparation on percutaneous delivery of complex components

This study aimed to investigate the transdermal enhancing effect of essential oil from Zanthoxylum bungeanum(Z. bungeanum oil) in microemulsion gel(ZO-ME-gel) on permeation of different components,and reveal the transdermal enhancing mechanism of ZO-ME-gel. A series of components with different log P values were selected as model drugs and encapsulated in ZO-ME-gel to simplify and characterize the complex components of traditional Chinese medicine. The transdermal behavior of the model drugs was further examined using the improved Franz diffusion cell method. Then attenuated total reflection Fourier transform infrared spectroscopy(ATR-FTIR),differential scanning calorimetry(DSC) studies and hematoxylin-eosin(HE) staining were used to investigate the effects of Z. bungeanum oil and ZO-ME-gel on keratin,intercellular lipids and microstructure of the stratum corneum(SC). The results showed that Z. bungeanum oil and ZO-ME-gel had a good transdermal enhancing effect on both hydrophilic and lipophilic drugs,and the best effect was achieved when log P value was-0. 5. The transdermal enhancing mechanism of Z. bungeanum oil and ZO-ME-gel was related to affecting the order of the SC lipids,changing lipid fluidity and protein conformation,and disrupting the integrity of the SC structure. 5% Z. bungeanum oil had greater transdermal enhancing effect and destruction of SC structure than ZO-ME-gel. These results suggested that Z. bungeanum oil loaded in microemulsion gel still had a good transdermal enhancing effect although the effect was not as great as Z. bungeanum oil itself,in addition,ZO-ME-gel was less irritating to the skin and safer to use,which had a guiding role in the development and clinical application of Z. bungeanum oil-containing traditional Chinese medicine topical preparations.

Antimicrobial and antibiofilm efficacy and mechanism of essential oil from Citrus Changshan-huyou Y. B. chang against Listeria monocytogenes

Listeria monocytogenes (L. monocytogenes) is an important foodborne pathogen which may cause listeriosis and poses potential risks to human health. The aim of this study was to estimate the efficacy of essential oil from Citrus Changshan-huyou Y.B. Chang (Huyou) on both planktonic cells and biofilm against L. monocytogenes, and further to elucidate the potential mechanism of this action. Results showed that Citrus Changshan-huyou Y.B. Chang essential oil (Huyou EO) exhibited significantly in vitro antimicrobial ability against L. monocytogenes, both of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations confirmed the physical damage, considerable morphological alteration and the leakage of intracellular constituents. Meanwhile, XTT and crystal violet (CV) assay indicated that Huyou EO was able to destroy preformed biofilm through decreasing the biomass and cellular activity. SEM, confocal scanning laser microscopy (CLSM) and COMSTAT analysis revealed the extensive disruption and architectural changes of biofilm. Moreover, the potential antimicrobial mechanisms were demonstrated by RNA sequencing. Enriched GO analysis identified 8 terms related to cellular components (CC), 50 terms for biological processes (BP) and 21 terms for molecular functions (MF). 35 pathways were significantly enriched in KEGG analysis. The transcriptome analysis offered novel antimicrobial molecular mechanisms of Huyou EO.

Antibacterial Activity and Mechanisms of Essential Oil from Citrus medica L. var. sarcodactylis.

In this work, antibacterial activity of finger citron essential oil (FCEO, Citrus medica L. var. sarcodactylis) and its mechanism against food-borne bacteria were evaluated. A total of 28 components in the oil were identified by gas chromatography-mass spectrometry, in which limonene (45.36%), γ-terpinene (21.23%), and dodecanoic acid (7.52%) were three main components. For in vitro antibacterial tests, FCEO exhibited moderately antibacterial activity against common food-borne bacteria: Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Micrococcus luteus. It showed a better bactericidal effect on Gram-positive bacteria than Gram-negative. Mechanisms of the antibacterial action were investigated by observing changes of bacteria morphology according to scanning electron microscopy, time-kill analysis, and permeability of cell and membrane integrity. Morphology of tested bacteria was changed and damaged more seriously with increased concentration and exposure time of FCEO. FCEO showed a significant reduction effect on the growth rate of surviving bacteria and lead to lysis of the cell wall, intracellular ingredient leakage, and consequently, cell death.

Inhalational aromatherapy for post-operative pain: The disturbed evidence

Analgesic therapy is the standard approach for postoperative pain which have some adverse effects. Integrative medicine can provide pain therapy without annoying side effects. The inhalational aromatherapy (AT) with essential oils has been widely applied for pain management. Application of AT in management of postoperative pain is challenging with doubtful results. There is insufficient evidence about the safety and efficacy of inhalational AT for pain reduction after surgery. To obtain conclusive results, researchers should conduct large-scale studies, consider the multifactorial aspects of pain and understand the different mechanisms of essential oils.

Chemical composition, antibacterial activity of Cyperus rotundus rhizomes essential oil against Staphylococcus aureus via membrane disruption and apoptosis pathway

The chemical composition, antibacterial activity and mechanism of essential oil from Cyperus rotundus rhizomes against Staphylococcus aureus were investigated in this study. Results showed that α-cyperone, cyperene and α-selinene were the major components of the essential oil. The essential oil exhibited strong antibacterial activity against S. aureus with the minimum inhibitory concentration (MIC) and minimum bactericide concentration (MBC) were 10 and 20 mg/mL respectively, and the antibacterial effects increased with increasing essential oil concentrations and treatment time. The electric conductivity, cell membrane integrity, NPN uptake, and membrane potential assays demonstrated that essential oil disrupted the membrane integrity of S. aureus. Electron microscope observations further confirmed that essential oil destroyed cell membrane. Moreover, we found that essential oil could induce cells death of S. aureus through apoptosis pathway based on apoptosis analysis. These findings suggested that essential oil mainly exerted antibacterial activity by damaging cell membrane and membrane-mediated apoptosis pathway.

Anti-cryptococcus Activity and Mechanism of Essential Oil from Coreopsis tinctoria Flowering on Cryptococcus

The essential oil (EO) extracted from the flower of Coreopsis tinctoria Nutt. is a kind of plant-derived natural therapeutics against Cryptococcus neoformans. In our study, the anti-cryptococcal effects of the EO were observed from various aspects, such as minimal inhibitory concentration, minimum fungicidal concentration, germ tube formation, and biomass. The results indicated that the EO had potent antifungal activities on C. neoformans and that it was more effective than the commonly used antifungal agents fluconazole and amphotericin B. To further elucidate the mechanism of the antifungal action, the effect of the EO on the plasma membrane and the mitochondria of C. neoformans were investigated. The lesion in the plasma membrane was detected through flow cytometry and was further verified through the inhibition of ergosterol synthesis. The essential oil caused morphological changes in the cells of C. neoformans and a reduction in the ergosterol quantity. Moreover, mitochondrial membrane potential, mitochondrial ATPase, succinate dehydrogenase (SDH), and malate dehydrogenase (MDH) were detected. The reactive oxygen species (ROS) accumulation was examined through fluorometric assay. Decreased SDH, MDH, and ATPase in C. neoformans cells were also observed in a dose-dependent manner. The above dysfunctions of the mitochondria caused ROS accumulation in C. neoformans. A reduction in cell viability was prevented through the addition of L-cysteine, and this reduction indicates that ROS is an important mediator of the antifungal action of the EO. In summary, EO from C. tinctoria flower showed anti-cryptococcus activity. Its mechanism of action is to disrupt the permeability barrier of the plasma membrane and the mitochondrial dysfunction-induced ROS accumulation in C. neoformans. With better antifungal activity than the commonly used antifungal agents and less possibility to induce drug resistance, the EO can be used as a potential anti-cryptococcal agent.

In vitro antifungal activity and mechanism of essential oil from fennel (Foeniculum vulgare L.) on dermatophyte species.

Fennel seed essential oil (FSEO) is a plant-derived natural therapeutic against dermatophytes. In this study, the antifungal effects of FSEO were investigated from varied aspects, such as MIC and minimum fungicidal concentration, mycelia growth, spore germination and biomass. The results indicated that FSEO had potent antifungal activities on Trichophyton rubrum ATCC 40051, Trichophyton tonsurans 10-0400, Microsporum gypseum 44693-1 and Trichophyton mentagrophytes 10-0060, which is better than the commonly used antifungal agents fluconazole and amphotericin B. Flow cytometry and transmission electron microscopy experiments suggested that the antifungal mechanism of FSEO was to damage the plasma membrane and intracellular organelles. Further study revealed that it could also inhibit the mitochondrial enzyme activities, such as succinate dehydrogenase, malate dehydrogenase and ATPase. With better antifungal activity than the commonly used antifungal agents and less possibility of inducing drug resistance, FSEO could be used as a potential antidermatophytic agent.