Essential Oils and Their Constituents: An Alternative Source for Novel Antidepressants

Application of Cinnamomum burmannii Essential Oil in Promoting Wound Healing

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

Antidepressant and anxiolytic potential of Citrus reticulata Blanco essential oil: a network pharmacology and animal model study

Background

Citrus reticulata Blanco essential oil (CBEO) has attracted increasing attention as a potential treatment for depression and anxiety in recent years. However, there is limited evidence regarding the active compounds responsible for its therapeutic effects. In addition, substantial amounts of CBEO and prolonged therapy are often required. This study aims to investigate the rapid acting antidepressant and anxiolytic effects of CBEO, identify the underlying composition as well as optimize its dosage and duration.

Methods

CBEO composition was determined using gas chromatography-mass spectrometry (GC-MS), and the corresponding targets were obtained from the SwissTargetPrediction database. Depression-related targets were collected from DisGeNET, GeneCards, Therapeutic Target Database, and Online Mendelian Inheritance in Man. Subsequently, the overlap between CBEO and depression targets was utilized to build a network diagram depicting the relationship between the active ingredients and targets using Cytoscape software. The STRING database facilitated the construction of a protein-protein interaction network, and the Ma'ayan Laboratory Enrichment tool was employed for Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Wiki pathway analyses. Molecular docking was conducted using AutoDock Vina and Discovery Studio Visualizer. Topological analysis predicted the main antidepressant active ingredients in CBEO. A mixture of these compounds was prepared based on their relative GC-MS ratios. Tail suspension test, elevated plus maze, corticosterone-induced PC12 cells, and lipopolysaccharide (LPS)-induced BV2 cells were used to validate the antidepressant and anxiolytic potential of CBEO and CBEO's main bioactive constituents.

Results

CBEO contains 18 components that target 121 proteins. We identified 595 targets associated with depression; among them, 29 targets were located between essential oils and depression. Topological results revealed that linalool, p-cymene, α-terpinene, terpinen-4-ol, and α-terpineol were the major active compounds of CBEO in the management of depression. GO analysis identified G protein-coupled opioid receptor activity, phospholipase C-activating G protein-coupled receptor, and neuron projections that were mostly related to molecular functions, cellular components, and biological processes. Neuroactive ligand-receptor interactions, chemical carcinogenesis, and calcium signaling pathways were the major pathways identified in KEGG analysis. Molecular docking showed that the main bioactive ingredients of CBEO had favorable binding affinities for Protein-Protein Interaction's hub proteins, including OPRM1, PTGS2, ESR1, SLC6A4, DRD2, and NR3C1. These five compounds were then mixed at 0.8:5:0.6:2:1 (w/w) ratio to form a CBEO antidepressant active compound mixture. An acute intranasal treatment of CBEO (25 mg/kg) only demonstrated an antidepressant effect, whereas the main bioactive compounds combination (12.5 mg/kg) illustrated both antidepressant and anxiolytic effects in mice. Linalool, p-cymene, and terpinene-4-ol exhibited neuroprotective and anti-neuroinflammation in the in vitro study, while these effects were not observed for α-terpinene and α-terpineol.

Conclusion

Linalool, p-cymene, α-terpinene, terpinen-4-ol, and α-terpineol cymene might be mainly contributing to CBEO's antidepressant effect by regulating neuroactive ligand-receptor interaction, neuron projection, and receptor signaling pathway. A mixture of these compounds showed rapid antidepressant potential via intranasal administration, which was comparable to that of CBEO. The mixture also exhibited an anxiolytic effect while not seen in CBEO.

Investigation of the Molecular Mechanisms Underlying the Therapeutic Effect of Perilla frutescens L. Essential Oil on Acute Lung Injury Using Gas Chromatography-Mass Spectrometry and Network Pharmacology

OBJECTIVE

The present study aimed to investigate the molecular mechanism through which Perilla essential oil treats acute lung injury (ALI) through network pharmacology, molecular docking, and in vitro assays.

METHODS

Relevant ALI targets of the active ingredients of Perilla essential oil were predicted using the SwissTargetPrediction database and meta TarFisher database. These ALI targets were then screened using GeneCards and DisGeNET, and differentially expressed ALI target genes were identified using the Gene Expression Omnibus (GEO) database. Next, key targets were enriched using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Protein-protein interaction network analysis was performed to obtain targets with the highest degree values for molecular docking with Perilla essential oil active ingredients. For in vitro experiments, lipopolysaccharide (LPS) was used to induce an ALI inflammation model using RAW264.7 cells. The model cells were then treated with Perilla essential oil to detect the protein expression levels of vascular endothelial factor (NO), tumor necrosis factor (TNF-α), and p65 nuclear transcription factor in them.

RESULTS

Sixty-eight key targets of Perilla oil were identified for the treatment of ALI. These targets were found to be involved in biological processes related to peptides, response to lipopolysaccharides, the positive regulation of cytokine production, etc., using GO. The signaling pathways found to be associated with the targets included the AGE-RAGE signaling pathway in diabetic complications, the NF-kappa B signaling pathway, and small cell lung cancer and other inflammatory signaling pathways. The five key targets that showed good binding activity with Perilla oil active ingredients included TNF, RELA, PARP1, PTGS2, and IRAK4. In vitro assays showed that Perilla essential oil could significantly reduce NO and TNF-α levels and inhibit the phosphorylation of nuclear transcription factor P65, thus inhibiting the activation of NF-κB signaling pathway. Conclusion Perilla essential oil can play a role in the treatment of ALI by inhibiting the activation of the NF-κB signaling pathway and preventing an excessive inflammatory response. This study thus provides a reference for the in-depth study of the mechanisms through which Perilla essential oil treats ALI.

Essential Oils: Chemistry and Pharmacological Activities

In this review, we provide an overview of the current understanding of the main mechanisms of pharmacological action of essential oils and their components in various biological systems. A brief introduction on essential oil chemistry is presented to better understand the relationship of chemical aspects with the bioactivity of these products. Next, the antioxidant, anti-inflammatory, antitumor, and antimicrobial activities are discussed. The mechanisms of action against various types of viruses are also addressed. The data show that the multiplicity of pharmacological properties of essential oils occurs due to the chemical diversity in their composition and their ability to interfere with biological processes at cellular and multicellular levels via interaction with various biological targets. Therefore, these natural products can be a promising source for the development of new drugs.

Polymeric nanoparticles for enhanced delivery and improved bioactivity of essential oils

Essential oils are volatile constituents that give aromatic plants their characteristic odour. The application of these plant actives in food, agriculture, pharmaceutics, and cosmetics has been widely studied. Aromatherapy, a complementary therapy involving the use of essential oils to treat several diseases ranging from microbial infections to metabolic dysfunctions, has been utilised for centuries. Anticancer, antimicrobial, and anti-inflammatory activities are well-established among other pharmacological properties of these aromatic oils. The oils, which are composed mainly of terpene-based compounds, have also been explored as nutraceuticals, alternative green preservatives, and functional additives in foods. However, due to their physicochemical properties, viz high volatility and low aqueous solubility, essential oil delivery to target receptors were challenging when administered as chemotherapeutics. Hence, formulating essential oils with suitable excipients to enhance their delivery and bioavailability, invariably improving their bioactivity and therapeutic efficacy becomes expedient. Nanotechnology presents a unique strategy to develop a particulate delivery system for the controlled, sustained, and extended release of essential oils. In this review, we examine and summarize the trends and developments in the formulation of essential oils using polymeric nanoparticles.

Antidepressant Effects of Essential Oils: A Review of the Past Decade (2012-2022) and Molecular Docking Study of Their Major Chemical Components

Depression is a mental disorder that affects more than 300 million people worldwide. The medications available for treatment take a long time to exhibit therapeutic results and present several side effects. Furthermore, there is a decrease in the quality of life of people suffering from this affliction. Essential oils are traditionally used to relieve the symptoms of depression due to the properties of the constituents of these oils to cross the blood-brain barrier acting on depression-related biological receptors associated with reduced toxicity and side effects. In addition, compared to traditional drugs, they have several administration forms. This review provides a comprehensive assessment of studies on plants whose essential oil has exhibit antidepressant activity in the past decade and the mechanism of action of the major components and models tested. An additional in silico study was conducted with the frequent compounds in the composition of these essential oils, providing a molecular approach to the mechanism of action that has been reported in the past decade. This review is valuable for the development of potential antidepressant medications in addition to providing a molecular approach to the antidepressant mechanism of action of the major volatile compounds that have been reported in the past decade.

Preparation, Characterization, and Application of Modified Starch/Chitosan/Sweet Orange Oil Microcapsules

Aquatic products have an important role in global agriculture, but the challenges associated with preservation have limited their marketability. Essential oil (EO), such as sweet orange oil (SOEO), has been widely used for preservation due to its excellent antibacterial ability. However, the volatilization of EO limits its application in food preservation. In this study, SOEO was extracted from sweet orange peel by steam distillation and then stored in microcapsules. The components of the microcapsules were as follows: the porous starch was chosen as an adsorbed substrate to store SOEO (PS/SOEO), and sodium alginate (SA) and chitosan (CMCS) were used as shell material to delay the volatilization of SOEO using the sharp pore coagulation method. Our results showed that the main antibacterial ingredients in SOEO were aldehydes (33.93%) and d-limonene (15.38%). The microcapsules were of an irregular shape (oval), and the size of the microcapsules was 1.2 ± 0.1 cm as measured by a digital micrometer. Scanning electron microscopy (SEM) results showed that there were a lot of pores on the surface of the starch after modification, but sodium alginate and chitosan could well encapsulate these pores. The results of Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis also showed that SOEO was successful encapsulated into the porous starch. The results of compression test and releasing kinetics studies suggested that CMCS and SA improved the mechanical and slow-releasing ability of SOEO microcapsules. The best antibacterial performance was obtained when 0.8 g of SOEO microcapsules was added. Finally, the shelf life of crawfish could be extended to 6 days by SOEO microcapsule (1/10 g, SOEO microcapsule/crawfish) under room temperature. These results provide a systematic understanding of the antibacterial capabilities of sweet orange essential oil microcapsules, which can contribute to the development of preservation methods for aquatic products.

Inhalation Aromatherapy via Brain-Targeted Nasal Delivery: Natural Volatiles or Essential Oils on Mood Disorders

Mood disorders, also often referred to as affective disorders, are a group of psychiatric illnesses that severely impact mood and its related functions. The high medical expenditures have placed a significant financial burden on patients and their families. Aromatherapy is an alternative and complementary treatment that utilizes essential oils (EOs) or volatile oils (VOs) to achieve major therapeutic goals. In general, EOs are volatile chemicals that enter the body primarily through skin absorption and/or nasal inhalation. In addition, they can work through oral administration. Inhalation aromatherapy has shown unique advantages for treating mood disorders, especially depression, anxiety and mental disorders such as sleep disorder, which have been validated over the last decade through clinical and animal studies. Accumulating evidence has shown that EOs or VOs can bypass the blood-brain barrier to target brain tissue through the nasal-brain pathway. Subsequently, they act on the cerebral cortex, thalamus, and limbic system in the brain to improve symptoms of anxiety, depression and improve sleep quality. Here, we review the natural aromatic plants’ volatiles or essential oils used commonly as adjuncts to manage mood disorders and illustrate the mechanisms of inhalation aromatherapy, and mainly summarized the application of transnasal inhalation aromatherapy in depression, anxiety, and sleep disorders. We conclude that aromatherapy does not cause side-effects, which is vastly different from commonly used psychotropic drugs. Inhalation aromatherapy via brain-targeted nasal delivery offers potentially efficacious treatment for mental disorders and merits further study.

Essential Oils, Phytoncides, Aromachology, and Aromatherapy—A Review

Chemical compounds from plants have been used as a medicinal source for various diseases. Aromachology is a unique field that studies the olfactory effects after inhaling aromatic compounds. Aromatherapy is a complementary treatment methodology involving the use of essential oils containing phytoncides and other volatile organic compounds for various physical and mental illnesses. Phytoncides possess an inherent medicinal property. Their health benefits range from treating stress, immunosuppression, blood pressure, respiratory diseases, anxiety, and pain to anti-microbial, anti-larvicidal, anti-septic, anti-cancer effects, etc. Recent advancements in aromatherapy include forest bathing or forest therapy. The inhalation of phytoncide-rich forest air has been proven to reduce stress-induced immunosuppression, normalize immune function and neuroendocrine hormone levels, and, thus, restore physiological and psychological health. The intricate mechanisms related to how aroma converts into olfactory signals and how the olfactory signals relieve physical and mental illness still pose enormous questions and are the subject of ongoing research. Aromatherapy using the aroma of essential oils/phytoncides could be more innovative and attractive to patients. Moreover, with fewer side effects, this field might be recognized as a new field of complementary medicine in alleviating some forms of physical and mental distress. Essential oils are important assets in aromatherapy, cosmetics, and food preservatives. The use of essential oils as an aromatherapeutic agent is widespread. Detailed reports on the effects of EOs in aromatherapy and their pharmacological effects are required to uncover its complete biological mechanism. This review is about the evolution of research related to phytoncides containing EOs in treating various ailments and provides comprehensive details from complementary medicine.

Natural products for the treatment of stress-induced depression: Pharmacology, mechanism and traditional use

ETHNOPHARMACOLOGICAL RELEVANCE

Depression, one of the most common psychiatric disorders, is the fourth leading cause of long-term disability worldwide. A series of causes triggered depression, including psychological stress and conflict, as well as biological derangement, among which stress has a pivotal role in the development of depression. Traditional herbal medicine has been used for the treatment of various disorders including depression for a long history with multi-targets, multi-levels and multi-ways, attracting great attention from scholars. Recently, natural products have been commercialized as antidepressants which have become increasingly popular in the world health drug markets. Major research contributions in ethnopharmacology have generated and updated vast amount of data associated with natural products in antidepressant-like activity.

AIMS OF THE REVIEW

This review aims to briefly discuss the pathological mechanism, animal models of stress-induced depression, traditional use of herbal medicines and especially recapitulate the natural products with antidepressant activity and their pharmacological functions and mechanism of action, which may contribute to a better understanding of potential therapeutic effects of natural products and the development of promising drugs with high efficacy and low toxicity for the treatment of stress-induced depression.

MATERIALS AND METHODS

The contents of this review were sourced from electronic databases including PubMed, Sci Finder, Web of Science, Science Direct, Elsevier, Google Scholar, Chinese Knowledge On frastructure (CNKI), Wan Fang, Chinese Scientific and Technological Periodical Database (VIP) and Chinese Biomedical Database (CBM). Additional information was collected from Yao Zhi website (https://db.yaozh.com/). Data were obtained from April 1992 to June 2021. Only English language was applied to the search. The search terms were 'stress-induced depression', 'pathological mechanism' in the title and 'stress', 'depression', 'animal model' and 'natural products' in the whole text.

RESULTS

Stress-induced depression is related to the monoaminergic system, hypothalamic-pituitary-adrenal (HPA) axis, neuronal plasticity and a series of inflammatory factors. Four main types of animal models of stress-induced depression were represented. Fifty-eight bioactive phytochemical compounds, fifty-six herb medicines and five formulas from traditional Chinese medicine were highlighted, which exert antidepressant effects by inhibiting monoamine oxidase (MAO) reaction, alleviating dysfunction of the HPA axis and nerve injury, and possessing anti-inflammatory activities.

CONCLUSIONS

Natural products provide a large number of compounds with antidepressant-like effects, and their therapeutic impacts has been highlighted for a long time. This review summarized the pathological mechanism and animal models of stress-induced depression, and the natural products with antidepressant activity in particular, which will shed light on the action mechanism and clinical potential of these compounds. Natural products also have been a vital and promising source for future antidepressant drug discovery.

Effectiveness of aromatherapy for intrapartum and postpartum emotional problems among parturient women: A meta-analysis of randomized controlled trials

AIM

Perinatal negative emotions are common in parturient women, but the problems are often ignored. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) that investigated the effectiveness of aromatherapy for intrapartum anxiety (IPA) and postpartum emotional symptoms (PES).

METHODS

We searched PubMed, Embase, Cochrane library, and ClinicalTrials.gov to identify suitable RCTs for analysis, and the study was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

RESULTS

Nine RCTs were included. The meta-analysis showed aromatherapy reduced IPA during the early to active phase (standardized mean difference [SMD]: -1.56 [-2.55, -0.61]) and during the transition phase (SMD: -3.30 [-4.97, -1.63]) when compared with controls. For the postpartum period, the meta-analyses showed a reduction of postpartum depression (PPD) at week 2 (SMD: -0.43 [-0.82, -0.03]), and a non-significant trend toward the reduction of PPD at weeks 4-6 (SMD: -0.70 [-1.40, 0.01]).

CONCLUSION

Our study found some evidence supporting the effectiveness of aromatherapy in reducing intrapartum anxiety and PES. We recommend the optional use of aromatherapy for intrapartum and postpartum care.

Integrated Network Pharmacology and GC-MS-Based Metabolomics to Investigate the Effect of Xiang-Su Volatile Oil Against Menopausal Depression

Menopausal depression perplexes a great number of women in later life. Xiangfu-Zisu (Xiang-Su), a traditional Chinese herbal pair composed of rhizomes of Cyperus rotundus L. (Xiangfu) and leaves of Perilla frutescens (L.) Britt. (Zisu), is frequently reported with antidepressant-like effects. The volatile oil from Xiangfu and Zisu has shown good antidepressant action, but its mechanism is still unclear. This study aimed to investigate the pharmacological mechanism of Xiang-Su (XS) volatile oil against menopausal depression through gas chromatography–mass spectrometry (GC-MS)-based network pharmacology and metabolomics. First, ADME screening was performed on actual detected components of XS volatile oil to obtain active constituents, and then duplicates of active constituent–related targets and menopausal depression–related targets were collected. These duplicates were considered as targets for XS volatile oil against menopausal depression, followed by GO and KEGG enrichment analyses. It showed that a total of 64 compounds were identified in XS volatile oil, and 38 active compounds were screened out. 42 overlapping genes between 144 compound-related genes and 780 menopausal depression–related genes were obtained. Results showed that targets of SLC6A4 and SLC6A3, regulation of serotonergic and dopaminergic synapses, were involved in the antidepressant mechanism of XS volatile oil. Next, antidepressant-like effect of XS volatile oil was validated in menopausal rats by ovariectomy (OVX) combined with chronic unpredictable mild stress (CUMS). Behavioral tests, biochemical analysis, and GC-MS–based non-targeted plasma metabolomics were employed to validate the antidepressant effect of XS volatile oil. Experimental evidence demonstrated that XS volatile oil reversed behavioral parameters in the sucrose preference test (SPT), open-field test (OFT), forced swim test (FST), and serum estradiol levels in OVX rats. Furthermore, results of metabolomics indicated that XS volatile oil mainly acts on regulating metabolic pathways of phenylalanine, tyrosine and tryptophan biosynthesis, tyrosine metabolism, and tryptophan metabolism, which were corresponding with the above-predicted results. These data suggest that network pharmacology combined with metabolomics provides deep insight into the antidepressant effect of XS volatile oil, which includes regulating key targets like SLC6A4 and SLC6A3, and pathways of serotonergic and dopaminergic synapses.

Essential oils for agitation in dementia [rELOAD]: A pragmatic, cluster-randomized, placebo-controlled, pilot feasibility trial

BACKGROUND

Clinical guidelines recommend non-pharmacological interventions as the first line of treatment for agitation in dementia. One intervention that shows some promise as a treatment for agitation is essential oils. The objective of this study was to provide preliminary evidence of the effectiveness and feasibility of using topically-administered, individualized essential oil preparations for the alleviation of agitation in persons with dementia.

METHODS

We conducted a 10-week pragmatic, cluster-randomized, placebo-controlled, pilot feasibility trial to compare the effectiveness of topically-administered, individualized essential oil preparations to control (placebo) preparations. Outcomes included frequency and severity of agitation, quality of life, frequency of antipsychotic medication use and physical restraint, incidence of adverse events, and trial feasibility. Participants with dementia and clinically significant agitation were recruited from five residential aged-care facilities across regional South Australia.

RESULTS

Thirty-eight participants were randomized from five sites. Accounting for random effects, we found statistically significant differences between the intervention and control groups in Pittsburgh Agitation Scale (PAS) aberrant vocalization sub score, Cohen Mansfield Agitation Inventory (CMAI) verbally agitated sub score and CMAI total score at week 4, but not at weeks 8 (post-intervention) or 10 (follow-up). No significant time-group interactions were observed for other PAS/CMAI scores or sub scores, quality of life - Alzheimer's disease total score, or frequency of physical restraint or as-needed antipsychotic medication. No adverse events were reported in any group.

CONCLUSIONS

The study findings highlight some promising effects of topically-administered, individualized essential oil preparations for agitation in dementia, and indicate that a large multi-center, cluster-randomized controlled trial of this treatment is feasible.

TRIAL REGISTRATION

Australian New Zealand Clinical Trial Registry [ACTRN12617001159347].

Selective Serotonin Reuptake Inhibitors and Nutraceutical Combination in Major Depression Disorder: A Case-Control Study

INTRODUCTION

Major depressive disorder (MDD) is a primary cause of disability in adults, affecting daily functioning and decreasing quality of life. The focus on the role of nutraceuticals as adjunctive treatments to improve antidepressant response is paying growing interest. The study aims to compare the antidepressants response in the utilization of selective serotonin reuptake inhibitors (SSRIs) versus a combination of SSRIs and nutraceutical supplements based on S-Adenosyl methionine (SAMe), N-acetylcysteine (NAC) and folate in terms of efficacy and tolerability.

METHODS

A case-control study was carried out between March 2018 and September 2019. Cases and controls were evaluated through the following scales: Hospital Anxiety Depression Scale (HADS); Clinical Global Impression (CGI); Patient Global Impression of Improvement (PGI-I); Antidepressant Adverse Events checklist (AES).

RESULTS

A significant difference between the two groups of patients emerged at T₁ in the HADS-A (p = 0.004) score and in the CGI score (p = 0.01), due to a major improvement in patients with a nutraceutical co-prescription. At T₃ a significant statistical difference emerged, showing a greater improvement at HADS-D in the case group (p = 0.006), confirmed by a higher remission rate in patients taking a nutraceutical co-prescription. No differences in terms of adverse events emerged.

CONCLUSION

This study shows promising data about the role of nutraceuticals as adjunctive treatment in major depressive disorder to improve SSRIs efficacy, with good tolerability. More data are needed to confirm these results, particularly about the role of nutraceuticals to decrease the latency of SSRIs response.

Anxiolytic effects of essential oils may involve anti-oxidant regulation of the pro-oxidant effects of ascorbate in the brain

Essential oils (EOs) absorbed via inhalation are consistently reported to produce anxiolytic effects. The underlying neurochemical mechanisms, however, are not well understood. High concentrations of ascorbate in the human brain (~10 mM in neurons) implicates this compound as a key signaling molecule and regulator of oxidative stress. In this study, we demonstrate the significant in vitro capacity of ascorbate to produce H₂O₂ in the presence of oxygen at physiological pH values, peaking at ~400 μM for ascorbate levels of 1.0 mg/mL (5.6 mM). In comparison, individual EOs and selected neurotransmitters at similar concentrations produced <100 μM H₂O₂. Systematic studies with binary and ternary mixtures containing ascorbate indicated that EOs and neurotransmitters could variably enhance (pro-oxidant, POX) or suppress (anti-oxidant, AOX) the production of H₂O₂ versus the ascorbate control, depending on the concentration ratios of the components in the mixture. Moreover, the AOX/POX chemistry observed with binary mixtures did not necessarily predict effects with ternary mixtures, where the POX ascorbate chemistry tended to dominate. A model is proposed to account for the ability of compounds with electron-donating capacity to catalytically regenerate ascorbate from intermediate oxidized forms of ascorbate, thus driving H₂O₂ production and exerting a net POX effect; whilst compounds that irreversibly reacted with oxidized forms of ascorbate suppressed the production of H₂O₂ and produced an overall AOX effect. Since the anxiolytic effects of different EOs, including extracts of Lavendula angustifolia (lavender) and Salvia rosmarinus (rosemary), were associated with AOX regulation of H₂O₂ production by ascorbate, it can be concluded that these anxiolytic effects are potentially related to the AOX properties of EOs. In contrast, EOs driving POX effects (eg, Junipenus communis (Juniper) berry EO) are proposed to be more useful for their potential anti-microbial or cancer cytotoxic applications.

Behavioural and biochemical indications of the antidepressant activities of essential oils from Monodora myristica (Gaertn) seed and Xylopia aethiopica (Dunal) fruit in rats

Monodora myristica and Xylopia aethiopica are two underutilised spices that are hypothesized to be important in the management and treatment of certain stress-induced diseases such as depression. The present study was designed to test the anti-depressant effects of the essential oils of Monodora myristica (EOMM) and Xylopia aethiopica (EOXA) and the possible underlying mechanisms in a chronic unpredictable mild stress (CUMS) - induced depression in the rat. Forty-two male Wistar rats were assigned to seven groups (n = 6); group I received corn oil (p.o, unstressed control), group II (stressed control) administered corn oil, groups III-IV received EOMM (150 & 300 mg/kg, p.o), groups V – VI received EOXA (150 & 300 mg/kg, p.o) whereas group VII had fluoxetine (10 mg/kg, p.o in d/w). Corn oil served as the vehicle for the delivery of the essential oils and the doses were administered via gastric intubation to rat once daily for six consecutive weeks from the 2nd week. Open-field, tail suspension (TST), and forced swimming (FST) tests were used to evaluate the behavioural activity in addition to the biochemical parameters (catalase, superoxide dismutase, reduced glutathione, monoamine oxidase, corticosterone, protein carbonyl compound, malondialdehyde and nitric oxide). The result showed that the administration of EOMM (150 and 300 mg/kg b.wt.) and EOXA (150 and 300 mg/kg b.wt.) during CUMS significantly ameliorated these behavioural activities and some biochemical parameters in rats. EOMM and EOXA exhibited significant antidepressant-like effects in a rat model of CUMS. At treatment doses of especially 300 mg/kg b.wt, the antidepressant effects of EOMM and EOXA are comparable to a standard antidepressant drug, fluoxetine (Prozac ™). The EOXA especially at a dose of 300 mg/kg b.wt is more effective than EOMM even at 300 mg/kg dose level in ameliorating depression in stressed rats. In conclusion, the study revealed that both the EOXA and EOMM relieved depression-like states through the mitigation of oxidative stress with a reduction in serum Corticosterone (CORT) and brain Monoamine Oxidase-A (MAO-A) levels.

Halogen Complexes of Anionic N-Heterocyclic Carbenes

The lithium complexes [(WCA-NHC)Li(toluene)] of anionic N-heterocyclic carbenes with a weakly coordinating anionic borate moiety (WCA-NHC) reacted with iodine, bromine, or CCl4 to afford the zwitterionic 2-halogenoimidazolium borates (WCA-NHC)X (X=I, Br, Cl; WCA=B(C6 F5 )3 , B{3,5-C6 H3 (CF3 )2 }3 ; NHC=IDipp=1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene, or NHC=IMes=1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene). The iodine derivative (WCA-IDipp)I (WCA=B(C6 F5 )3 ) formed several complexes of the type (WCA-IDipp)I⋅L (L=C6 H5 Cl, C6 H5 Me, CH3 CN, THF, ONMe3 ), revealing its ability to act as an efficient halogen bond donor, which was also exploited for the preparation of hypervalent bis(carbene)iodine(I) complexes of the type [(WCA-IDipp)I(NHC)] and [PPh4 ][(WCA-IDipp)I(WCA-NHC)] (NHC=IDipp, IMes). The corresponding bromine complex [PPh4 ][(WCA-IDipp)2 Br] was isolated as a rare example of a hypervalent (10-Br-2) system. DFT calculations reveal that London dispersion contributes significantly to the stability of the bis(carbene)halogen(I) complexes, and the bonding was further analyzed by quantum theory of atoms in molecules (QTAIM) analysis.

Investigation of Potential Antioxidant, Thrombolytic and Neuropharmacological Activities of Homalomena aromatica Leaves Using Experimental and In Silico Approaches

The leaves of Homalomena aromatica are traditionally used in Bangladesh for the treatment of different chronic ailments. The purpose of this study was to explore in vitro antioxidant, thrombolytic activities, and in vivo neuropharmacological effects of methanolic extract of Homalomena aromatica (MEHA) leaves. Antioxidant activity of MEHA was assessed by a DPPH free radical scavenging assay and total phenolics content, total flavonoids content were also measured. The thrombolytic activity was determined by percentage of clot lysis and neuropharmacological activities by hole board, tail suspension, forced swimming and elevated plus maze tests. The results showed that the IC₅₀ value of the extract against DPPH was 199.51 μg/mL. Quantitative analysis displayed higher contents of phenolics and flavonoids (147.71 mg gallic acid equivalent/g & 66.65 mg quercetin equivalent/g dried extract, respectively). The extract also showed a significant clot lysis (33.31%) activity. In case of anxiolytic activity, the elevate plus maze (EPM) test demonstrated an increase in time spent in open arms, and in case of hole board test, the number of head dipping was also significantly increased (p < 0.05). All the test compared with control (1% Tween in water) and standard (diazepam 1 mg/kg), significant dose (200 & 400 mg/kg) dependent anxiolytic activity was found. In antidepressant activity, there was a significant decrease in period of immobility in both test models (tail suspension and forced swimming) (p < 0.05). Moreover, 13 compounds were identified as bioactive, showed good binding affinities to xanthine oxidoreductase, tissue plasminogen activator receptor, potassium channel receptor, human serotonin receptor targets in molecular docking experiments. Furthermore, ADME/T analysis revealed their drug-likeness, likely pharmacological actions and non-toxic upon consumption. Taken together, our finding support the traditional medicinal use of this plant, which may provide a potential source for future drug discovery.

Anxiety Therapeutic Interventions of β-Caryophyllene: A Laboratory-Based Study

The bicyclic sesquiterpene β-caryophyllene (BCP) has diverse biological activities, including antioxidant, anti-inflammatory, antidiabetic, and analgesic effects. This study evaluates anxiolytic, toxicity, and antioxidant effects of BCP using in vitro and in vivo test models. The anxiolytic effects were tested in Swiss albino mice ( Mus musculus) by applying the elevated plus-maze, rota-rod, light and dark, and hiding sphere models, while the toxicity was evaluated by brine shrimp ( Artemia salina) lethality bioassay. Additionally, the antioxidant capacity was tested by using 2,2-diphenyl-1-picrylhydrazyl radical, 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid hydroxyl radical scavenging, and the Saccharomyces cerevisiae test model. The results suggest that BCP exerted a dose-dependent anxiolytic-like effect on the experimental animals. It did not show toxicity in A. salina at 24 hours. BCP showed a concentration-dependent free-radical-scavenging capacity, similar to the standard antioxidant Trolox. It also showed protective and repair capacities against hydrogen peroxide-induced damaging effects in isogenic and wild-type S. cerevisiae strains. Taken together, BCP exerted antioxidant and protective effects, which can be targeted to treat neurological diseases and disorders such as anxiety.

(-)-cis-Carveol, a Natural Compound, Improves β-Amyloid-Peptide 1-42-Induced Memory Impairment and Oxidative Stress in the Rat Hippocampus

Alzheimer's disease (AD) could be considered a multifactorial neurodegenerative disorder characterized by the accumulation of the β-amyloid-peptide (Aβ) within the brain leading to cognitive deficits, oxidative stress, and neuroinflammation. The present work was carried out to investigate the neuroprotective effect of (-)-cis-carveol (1% and 3%, for 21 days) against the β-amyloid-peptide 1-42- (Aβ1-42-) induced AD. Twenty-five rats were divided into five groups (n = 5/group): the first group-control (sham-operated); the second group-Aβ1-42 (1 mM) that received donepezil treatment (5 mg/kg, as the positive reference drug in the Y-maze and the radial arm maze tests); the third group-Aβ1-42 (1 mM); the fourth and fifth groups-Aβ1-42 (1 mM) that received (-)-cis-carveol treatment groups (1% and 3%). The results of this study demonstrated that (-)-cis-carveol improved Aβ1-42-induced memory deficits examined by using Y-maze and radial arm maze in vivo tests. Also, the biochemical analyses of the hippocampus homogenates showed that (-)-cis-carveol reduced hippocampal oxidative stress caused by Aβ1-42. Our results suggested that the use of (-)-cis-carveol may be suitable for decreasing AD-related symptoms.

S-Adenosylmethionine (SAMe) monotherapy for depression: an 8-week double-blind, randomised, controlled trial

RATIONALE

Dysregulation of the one carbon cycle is documented in depression. Thereby, S-adenosylmethionine (SAMe), a one-carbon cycle nutraceutical compound with a favourable side effect profile, has a theoretical rationale for efficacy. However, further controlled studies are required to confirm SAMe's efficacy.

OBJECTIVES

To test the efficacy of SAMe versus placebo in unmedicated DSM-5 diagnosed (major depressive disorder) (MDD) patients with mild-to-moderate levels of depressive symptoms.

METHODS

We conducted an 8-week, double-blind, randomised controlled trial testing 800 mg/day of SAMe monotherapy versus placebo in 49 patients with MDD (Montgomery-Åsberg Depression Rating Scale [MADRS] score 14-25) who were not currently taking antidepressants. One-carbon cycle biomarkers, brain-derived neurotropic factor (BDNF), and relevant single nucleotide polymorphisms (SNPs) were analysed as potential treatment moderators.

RESULTS

A clinically relevant differential reduction from baseline to week 8 of 3.76 points occurred on the primary outcome (MADRS) in favour of SAMe. This however was not significant (p = 0.13) on an adjusted linear mixed model, notwithstanding a medium to large effect size of 0.72. A high placebo response rate of 53% occurred (> 50% reduction on MADRS). Exploratory analyses showed that SAMe was however effective in reducing depression amongst participants with milder depression severity (MADRS ≤ 22, p = 0.045). Response was not moderated by BDNF, SNPs, or one-carbon cycle biomarkers, although increased folate concentrations were correlated with improved symptoms in the SAMe group (r = - 0.57, p = 0.026). The treatment was safe and well tolerated.

CONCLUSIONS

Although a differential reduction in depression symptoms between groups was observed in favour of SAMe, the results of this pilot study were not statistically significant.

TRIAL REGISTRATION

ANZCTR-Australian New Zealand Clinical Trials Registry; No.: ACTRN12613001299796; URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=364900.

Lead optimization for promising monoamine oxidase inhibitor from eugenol for the treatment of neurological disorder: synthesis and in silico based study

Natural based inhibitors of monoamine oxidase are promising drug candidates for the treatment of several neurodegenerative and neuropsychological disorders including depression, anxiety, Parkinson’s disease and Alzheimer’s disease. In the present study we designed and synthesized the eugenol based derivatives and investigated them for human MAO inhibitory potential as promising candidates for therapeutics of neurological disorders. Moreover, radical scavenging activity of designed derivatives was tested by and H₂O₂ and DPPH scavenging methods. Eugenol based derivatives were designed and synthesized for human MAO inhibitory action. The in silico and in vitro models were utilized for the evaluation of hMAO inhibition. The insight into molecular interactions among the compounds and both hMAO-A and hMAO-B active site was achieved by molecular docking studies. The two spectrophotometric titrations techniques were used to evaluate antioxidant potential. Compounds 5b and 16 were found as most active hMAO-A inhibitors with IC₅₀ values of 5.989 ± 0.007 µM and 7.348 ± 0.027 µM respectively, through an appreciable selectivity index value of 0.19 and 0.14 respectively. In case of hMAO-B inhibition compounds 13a and 13b were found as most active hMAO-B inhibitors with IC₅₀ values of 7.494 ± 0.014 µM and 9.183 ± 0.034 µM receptively and outstanding value of selectivity index of 5.14 and 5.72 respectively. Radical scavenging assay showed that compounds 5b, 5a, 9b, 9a were active antioxidants. The findings of present study indicated excellent correlation among dry lab and wet lab hMAO inhibitory experiments. Interestingly, the compounds exhibiting better MAO inhibition activity was also appeared as good antioxidant agents.

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

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