Screening for Neuroprotective and Rapid Antidepressant-like Effects of 20 Essential Oils

Molecular mechanism of Chang Shen Hua volatile oil modulating brain cAMP-PKA-CREB pathway to improve depression-like behavior in rats

BACKGROUND

Depression is a common and complex mental illness that manifests as persistent episodes of sadness, loss of interest, and decreased energy, which might lead to self-harm and suicide in severe cases. Reportedly, depression affects 3.8 % of the world's population and has been listed as one of the major global public health concerns. In recent years, aromatherapy has been widely used as an alternative and complementary therapy in the prevention and treatment of depression; people can relieve anxiety and depression by sniffing plant aromatic essential oils. Acorus tatarinowii and Panax ginseng essential oils in Chang Shen Hua volatile oil (CSHVO) are derived from Acorus tatarinowii and Panax ginseng, respectively, the main medicines in the famous Chinese medicine prescription Kai Xin San (KXS), Then, these oils are combined with the essential oil of Albizia julibrissin flower to form a new Chinese medicine inhalation preparation, CSHVO. KXS has been widely used in the treatment of depression; however, whether CSHVO can ameliorate depression-like behavior, its pharmacological effects, and the underlying mechanisms of action are yet to be elucidated.

STUDY DESIGN AND METHODS

A rat model of chronic and unpredictable mild stimulation (CUMS) combined with orphan rearing was treated with CSHVO for 4 weeks. Using behavioral tests (sucrose preference, force swimming, tail suspension, and open field), the depression-like degree was evaluated. Concurrently, brain homogenate and serum biochemistry were analyzed to assess the changes in the neurotransmitters and inflammatory and neurotrophic factors. Furthermore, tissue samples were collected for histological and protein analyses. In addition, network pharmacology and molecular docking analyses of the major active compounds, potential therapeutic targets, and intervention pathways predicted a role of CSHVO in depression relief. Subsequently, these predictions were confirmed by in vitro experiments using a corticosterone (CORT)-induced PC12 cell damage model.

RESULTS

CSHVO inhalation can effectively improve the weight and depression-like behavior of depressed rats and regulate the expression of inflammatory factors and neurotransmitters. Hematoxylin-eosin, Nissl, and immunofluorescence staining indicated that compared to the model group, the pathological damage to the brain tissues of rats in the CSHVO groups was improved. The network pharmacological analysis revealed that 144 CSHVO active compounds mediate 71 targets relevant to depression treatment, most of which are rich in the cAMP signaling and inflammatory cytokine pathways. Protein-protein interaction analysis showed that TNF, IL6, and AKT are the core anti-depressive targets of CSHVO. Molecular docking analysis showed an adequate binding between the active ingredients and the key targets. In vitro experiments showed that compared to the model group, the survival rate of PC12 cells induced by CSHVO intervention was increased, the apoptosis rate was decreased, and the expression of inflammatory cytokines in the cell supernatant was improved. Western blot analysis and immunofluorescence staining confirmed that CSHVO regulates PC12 cells in the CORT model through the cAMP-PKA-CREB signaling pathway, and pretreatment with PKA blocker H89 eliminates the protective effect of CSHVO on CORT-induced PC12 cells.

CONCLUSIONS

CSHVO improves CORT-induced injury in the PC12 cell model and CUMS combined with orphan rearing-induced depression model in rats. The antidepressant mechanism of CSHVO is associated with the modulation of the cAMP-PKA-CREB signaling pathway.

Discovery of GluN2A subtype-selective N-methyl-d-aspartate (NMDA) receptor ligands

The N-methyl-d-aspartate (NMDA) receptors, which belong to the ionotropic Glutamate receptors, constitute a family of ligand-gated ion channels. Within the various subtypes of NMDA receptors, the GluN1/2A subtype plays a significant role in central nervous system (CNS) disorders. The present article aims to provide a comprehensive review of ligands targeting GluN2A-containing NMDA receptors, encompassing negative allosteric modulators (NAMs), positive allosteric modulators (PAMs) and competitive antagonists. Moreover, the ligands' structure-activity relationships (SARs) and the binding models of representative ligands are also discussed, providing valuable insights for the clinical rational design of effective drugs targeting CNS diseases.

Intranasal administration of the essential oil from Perillae Folium ameliorates social defeat stress-induced behavioral impairments in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Perillae Folium, the leaves and twigs of Perilla frutescens (L.) Britton, has been included in many traditional Chinese medicine herbal formulas to treat depression. However, the precise antidepressant mechanism of the essential oil from Perillae Folium (PFEO) has not been fully investigated.

AIM OF THE STUDY

To assess the effects and potential mechanisms of PFEO on depression using animal models and network pharmacology analysis.

MATERIALS AND METHODS

PFEO was intranasally administered to a mouse model of social defeat stress (SDS). The antidepressant effects of PFEO on SDS-induced mice were evaluated using behavioral tests. Enzyme-linked immunosorbent assay (ELISA) and western blot were performed to measure the levels of depression-related biomarkers in the hippocampus and serum of the mice. The chemical compounds of PFEO were determined using gas chromatography-mass spectrometry (GC-MS). Network pharmacology and molecular docking analyses were conducted to investigate the potential bioactive components of PFEO and the mechanisms underlying the antidepressant effects. To validate the mechanisms of the bioactive compounds, in vitro models using PC12 and BV2 cells were established and the blood-brain barrier (BBB) permeability was evaluated.

RESULTS

The intranasal administration of PFEO suppressed SDS-induced depression in mice by increasing the time spent in the social zone and the social interactions in the social interaction test and by decreasing the immobility time in the tail suspension and forced swimming tests. Moreover, the PFEO treatment reduced the SDS-induced anxiety-like behavior, as inferred from the increased activity in the central zone observed in the open field test and in the open arms observed in the elevated plus maze test. PFEO administration recovered the SDS-induced decrease in the levels of 5-HT, NE, gamma-aminobutyric acid (GABA), and p-ERK in the hippocampus of mice. Furthermore, the increased serum corticosterone level was also attenuated by the PFEO treatment. A total of 21 volatile compounds were detected in PFEO using GC-MS, among which elemicin (15.52%), apiol (15.16%), and perillaldehyde (12.79%) were the most abundant ones. The PFEO compounds targeted 32 depression-associated genes, which were mainly related to neural cells and neurotransmission pathways. Molecular docking indicated good binding affinities between the bioactive components of PFEO (apiol, β-caryophyllene, elemicin, and myristicin) and the key targets, including ACHE, IL1B, IL6, MAOB, SLC6A2, SLC6A3, SLC6A4, and tumor necrosis factor. Among the four compounds, β-caryophyllene, elemicin, and myristicin were more effective in reducing neurotoxicity and neuroinflammation. Elemicin showed the highest BBB permeability rate.

CONCLUSIONS

This study shows the antidepressant activities of PFEO in an SDS-induced mouse model and suggests its potential mechanisms of action: regulation of the corticosterone levels, hippocampal neurotransmitters, and ERK signaling. Apiol, β-caryophyllene, elemicin, and myristicin may be the main contributors to the observed effects induced by PFEO. Further studies are needed to fully elucidate the underlying mechanisms and the main PFEO bioactive components.

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.

Diversity in storage age enables discrepancy in quality attributes and metabolic profile of Citrus grandis "Tomentosa" in China

The folk proverb "the older, the better" is usually used to describe the quality of Citrus grandis "Tomentosa" (CGT) in China. In this study, CGT aged for 6-, 12-, 16-, and 19-years were collected for the investigation of infusion color, main bioactive components, antioxidant activity, metabolic composition, and pathway. The results found that infusion color, the total phenolic and flavonoid, and antioxidant activity of CGT were obviously changed by aging process. Through untargeted metabolomics, 55 critical metabolites were identified to in discrimination of CGT with different storage ages, mainly including phenylpropanoids, lipids, and organic oxygen compounds. Twenty compounds that showed good linear relationships with storage ages could be used for year prediction of CGT. Kyoto encyclopedia of genes and genomes enrichment pathway analysis uncovered important metabolic pathways related to the accumulation of naringin, kaempferol, and choline as well as the degradation of benzenoids, thus supporting that aged CGT might be more beneficial to health. Correlation analysis provided that some key metabolites with bitter taste and biological activity were involved in the darkening and reddening of CGT infusion during aging, and total phenolic and flavonoid were more strongly associated with the antioxidant activity of CGT. This study systematically revealed the quality changes and key metabolic pathways during CGT aging at first time. PRACTICAL APPLICATION: This study reveals the differences in quality attributes and metabolic profile between CGT with different storage ages, providing guidance for consumers' consumption, and also providing more scientific basis for the quality evaluation and improvement of CGT.

Perry Disease: Bench to Bedside Circulation and a Team Approach

With technological applications, especially in genetic testing, new diseases have been discovered and new disease concepts have been proposed in recent years; however, the pathogenesis and treatment of these rare diseases are not as well established as those of common diseases. To demonstrate the importance of rare disease research, in this paper we focus on our research topic, Perry disease (Perry syndrome). Perry disease is a rare autosomal dominant neurodegenerative disorder clinically characterized by parkinsonism, depression/apathy, weight loss, and respiratory symptoms including central hypoventilation and central sleep apnea. The pathological classification of Perry disease falls under TAR DNA-binding protein 43 (TDP-43) proteinopathies. Patients with Perry disease exhibit DCTN1 mutations, which is the causative gene for the disease; they also show relatively uniform pathological and clinical features. This review summarizes recent findings regarding Perry disease from both basic and clinical perspectives. In addition, we describe technological innovations and outline future challenges and treatment prospects. We discuss the expansion of research from rare diseases to common diseases and the importance of collaboration between clinicians and researchers. Here, we highlight the importance of researching rare diseases as it contributes to a deeper understanding of more common diseases, thereby opening up new avenues for scientific exploration.

Lead Identification Through In Silico Studies: Targeting Acetylcholinesterase Enzyme Against Alzheimer's Disease

AIMS

In this work, we aimed to acquire the best potential small molecule for Alzheimer's disease (AD) treatment using different models in Biovia Discovery Studio to identify new potential inhibitors of acetylcholinesterase (AChE) via in silico studies.

BACKGROUND

The prevalence of cognitive impairment-related neurodegenerative disorders, such as AD, has been observed to escalate rapidly. However, we still know little about the underlying functions, outcome predictors, or intervention targets causing AD.

OBJECTIVES

The objective of the study was to optimize and identify the lead compound to target AChE against Alzheimer's disease.

METHODS

Different in silico studies were employed, including the pharmacophore model, virtual screening, molecular docking, de novo evolution model, and molecular dynamics.

RESULTS

The pharmacophoric features of AChE inhibitors were determined by ligand-based pharmacophore models and 3D QSAR pharmacophore generation. Further validation of the best pharmacophore model was done using the cost analysis method, Fischer's randomization method, and test set. The molecules that harmonized the best pharmacophore model with the estimated activity < 1 nM and ADMET parameters were filtered, and 12 molecules were subjected to molecular docking studies to obtain binding energy. 3vsp_EK8_1 secured the highest binding energy of 65.60 kcal/mol. Further optimization led to a 3v_Evo_4 molecule with a better binding energy of 70.17 kcal/mol. The molecule 3v_evo_4 was subjected to 100 ns molecular simulation compared to donepezil, which showed better stability at the binding site.

CONCLUSION

A lead compound, 3v_Evo_4 molecule, was identified to inhibit AChE, and it could be further studied to develop as a drug with better efficacy than the existing available drugs for treating AD.

Inflammatory Pathways in Overweight and Obese Persons as a Potential Mechanism for Cognitive Impairment and Earlier Onset Alzeihmer's Dementia in the General Population: A Narrative Review

The overweight status or obesity can be confirmed through classical methods such as the body mass index (BMI) and the waist-to-hip ratio (WHR). Apart from metabolic issues such as atherosclerosis, liver steatosis, or diabetes mellitus, long-term obesity or overweight status can pose a risk for cardiovascular and neurovascular complications. While some acute adverse events like coronary syndromes of strokes are well-documented to be linked to an increased body mass, there are also chronic processes that, due to their silent onset and evolution, are underdiagnosed and not as thoroughly studied. Through this review, we aimed to collect all relevant data with regard to the long-term impact of obesity on cognitive function in all ages and its correlation with an earlier onset of dementia such as Alzheimer's disease (AD). The exact mechanisms through which a decline in cognitive functions occurs in overweight or obese persons are still being discussed. A combination of factors has been acknowledged as potential triggers, such as a sedentary lifestyle and stress, as well as a genetic predisposition, for example, the apolipoprotein E (ApoE) alleles in AD. Most research highlights the impact of vascular dysfunction and systemic inflammation on the nervous system in patients with obesity and the subsequent neurological changes. Obesity during the early to mid-ages leads to an earlier onset of cognitive dysfunction in various forms. Also, lifestyle intervention can reverse cognitive dysfunction, especially dieting, to encourage weight loss.

Effects of Anxious Depression on Antidepressant Treatment Response

Anxious depression represents a subtype of major depressive disorder and is associated with increased suicidality, severity, chronicity and lower treatment response. Only a few studies have investigated the differences between anxious depressed (aMDD) and non-anxious depressed (naMDD) patients regarding treatment dosage, serum-concentration and drug-specific treatment response. In our naturalistic and prospective study, we investigated whether the effectiveness of therapy including antidepressants (SSRI, SNRI, NaSSA, tricyclics and combinations) in aMDD patients differs significantly from that in naMDD patients. In a sample of 346 patients, we calculated the anxiety somatization factor (ASF) and defined treatment response as a reduction (≥50%) in the Hamilton Depression Rating Scale (HDRS)-21 score after 7 weeks of pharmacological treatment. We did not observe an association between therapy response and the baseline ASF-scores, or differences in therapy outcomes between aMDD and naMDD patients. However, non-responders had higher ASF-scores, and at week 7 aMDD patients displayed a worse therapy outcome than naMDD patients. In subgroup analyses for different antidepressant drugs, venlafaxine-treated aMDD patients showed a significantly worse outcome at week 7. Future prospective, randomized-controlled studies should address the question of a worse therapy outcome in aMDD patients for different psychopharmaceuticals individually.

Deep-Brain Subthalamic Nucleus Stimulation Enhances Food-Related Motivation by Influencing Neuroinflammation and Anxiety Levels in a Rat Model of Early-Stage Parkinson's Disease

Deep-brain subthalamic nucleus stimulation (DBS-STN) has become a well-established therapeutic option for advanced Parkinson's disease (PD). While the motor benefits of DBS-STN are widely acknowledged, the neuropsychiatric effects are still being investigated. Beyond its immediate effects on neuronal circuits, emerging research suggests that DBS-STN might also modulate the peripheral inflammation and neuroinflammation. In this work, we assessed the effects of DBS-STN on food-related motivation, food intake pattern, and the level of anxiety and compared them with markers of cellular and immune activation in nigrostriatal and mesolimbic areas in rats with the 6-OHDA model of early PD. To evaluate the potential mechanism of observed effects, we also measured corticosterone concentration in plasma and leukocyte distribution in peripheral blood. We found that DBS-STN applied during neurodegeneration has beneficial effects on food intake pattern and motivation and reduces anxiety. These behavioral effects occur with reduced percentages of IL-6-labeled cells in the ventral tegmental area and substantia nigra pars compacta in the stimulated brain hemisphere. At the same brain structures, the cFos cell activations were confirmed. Simultaneously, the corticosterone plasma concentration was elevated, and the peripheral blood lymphocytes were reduced after DBS-STN. We believe that comprehending the relationship between the effects of DBS-STN on inflammation and its therapeutic results is essential for optimizing DBS therapy in PD.

From CGRP to PACAP, VIP, and Beyond: Unraveling the Next Chapters in Migraine Treatment

Migraine is a neurovascular disorder that can be debilitating for individuals and society. Current research focuses on finding effective analgesics and management strategies for migraines by targeting specific receptors and neuropeptides. Nonetheless, newly approved calcitonin gene-related peptide (CGRP) monoclonal antibodies (mAbs) have a 50% responder rate ranging from 27 to 71.0%, whereas CGRP receptor inhibitors have a 50% responder rate ranging from 56 to 71%. To address the need for novel therapeutic targets, researchers are exploring the potential of another secretin family peptide, pituitary adenylate cyclase-activating polypeptide (PACAP), as a ground-breaking treatment avenue for migraine. Preclinical models have revealed how PACAP affects the trigeminal system, which is implicated in headache disorders. Clinical studies have demonstrated the significance of PACAP in migraine pathophysiology; however, a few clinical trials remain inconclusive: the pituitary adenylate cyclase-activating peptide 1 receptor mAb, AMG 301 showed no benefit for migraine prevention, while the PACAP ligand mAb, Lu AG09222 significantly reduced the number of monthly migraine days over placebo in a phase 2 clinical trial. Meanwhile, another secretin family peptide vasoactive intestinal peptide (VIP) is gaining interest as a potential new target. In light of recent advances in PACAP research, we emphasize the potential of PACAP as a promising target for migraine treatment, highlighting the significance of exploring PACAP as a member of the antimigraine armamentarium, especially for patients who do not respond to or contraindicated to anti-CGRP therapies. By updating our knowledge of PACAP and its unique contribution to migraine pathophysiology, we can pave the way for reinforcing PACAP and other secretin peptides, including VIP, as a novel treatment option for migraines.

Insula Connectivity Abnormalities Predict Impulsivity in Chronic Heroin Use Disorder: A Cross-Sectional Resting-State fMRI Study

Patients with heroin use disorder (HUD) often exhibit trait impulsivity, which may be an important factor in and a good predictor of addiction. However, the factor structure of HUD trait impulsivity (motor, attentional, and nonplanning) and its neural correlates are not yet known. A total of 24 male volunteers with HUD and 16 healthy control volunteers were recruited for this cross-sectional study. The Barratt Impulsiveness Scale (BIS-11) and resting-state functional magnetic resonance imaging (rs-fMRI) were employed using the insula as a seed point in an effort to understand the association between trait impulsivity and its intrinsic factors and functional connectivity (FC) between the insula and the whole brain. The HUD group in this study exhibited higher total trait impulsivity scores, motor impulsivity, and nonplanning impulsivity than the control group. Changes in FC between the right insula and the lateral occipital cortex and the right angular gyrus were significantly positively correlated with total trait impulsivity scores, motor impulsivity, and nonplanning impulsivity, whereas changes in the FC between the left insula and the left superior frontal gyrus and left frontopolar brain region were significantly negatively correlated with trait impulsivity. Thus, the insula may serve as an important biomarker for identifying trait impulsivity and its intrinsic factor structure in patients with HUDs.

Investigation of the Mechanical Response of the Foot Structure Considering Push-Off Angles in Speed Skating

The push-off angle is an important factor affecting speed-skating performance. However, quantitative evidence for the relationship between the push-off angle and foot injury is incomplete. This study aimed to establish a three-dimensional (3D) finite element model (FEM) and investigate the mechanical responses of foot structures to stress and strain to explore the relationship between injury and movement. A 3D FEM was reconstructed using CT and 3D scan data and validated by comparing the FEM-predicted and in vivo measurement data in the balanced standing state. A push-off angle obtained from a video of a champion was loaded into the FEM. The error rates of validation were less than 10%. With a decrease in the push-off angle, the stress on the metatarsal increased; the stress on the talus, ankle joint cartilage and plantar fascia decreased, as did the strain on the ankle joint cartilage and plantar fascia. The FEM was considered reasonable. Not all foot structures had an increased risk of injury with a decrease in the push-off angle from 70° to 42°. The FEM established in this study provides a possibility for further determining and quantifying the relationship between foot injury and skating technique.