Tetrandrine exerts antidepressant-like effects in animal models: Role of brain-derived neurotrophic factor

New insights into anti-depression effects of bioactive phytochemicals

Depression is one of the most common psychological disorders, and due to its high prevalence and mortality rates, it imposes a significant disease burden. Contemporary treatments for depression involve various synthetic drugs, which have limitations such as side effects, single targets, and slow onset of action. Unlike synthetic medications, phytochemicals offer the benefits of a multi-target and multi-pathway mode of treatment for depression. In this literature review, we describe the pharmacological actions, experimental models, and clinical trials of the antidepressant effects of various phytochemicals. Additionally, we summarize the potential mechanisms by which these phytochemicals prevent depression, including regulating neurotransmitters and their receptors, the HPA axis, inflammatory responses, managing oxidative stress, neuroplasticity, and the gut microbiome. Phytochemicals exert therapeutic effects through multiple pathways and targets, making traditional Chinese medicine (TCM) a promising adjunctive antidepressant for the prevention, alleviation, and treatment of depression. Therefore, this review aims to provide robust evidence for subsequent research into developing phytochemical resources as effective antidepressant agents.

Depression-reminiscent Behavior Induced by Chronic Unpredictable Mild Stress Paradigm in Mice Substantially Abrogated by Diosmin

Background:

Diosmin has already been described and documented to be neuroprotective, antioxidant and anti-inflammatory. It may possess or hold depressionalleviating activity. Therefore, the purpose of the current research protocol is to investigate the depression-relieving proficiency of diosmin in stressed and unstressed mice.

Methods:

Male mice (Swiss albino) were imperiled to an unpredictable chronic stress paradigm every day for three sequential weeks, and depression-resembling behavioral despair was induced. Imipramine 15 mg/kg and diosmin (25, 50 and 100 mg/kg) were dispensed for 21 successive days to discrete groups of stressed and unstressed mice.

Results:

Both diosmin (100 mg/kg) and 15 mg/kg imipramine administration for 3 consecutive weeks substantially or significantly diminished the immobility period of mice imperiled to stress in comparison to stressed mice gauzed with the vehicle. Diosmin (25, 50 and 100 mg/kg) and imipramine considerably reinstated the diminished sucrose proclivity (sucrose preference percentage; %) in stressed mice, demonstrating their considerable or substantial depression-relieving effects. The locomotor activities of mice were not considerably altered by these drugs. Antidepressant-like activity of diosmin for immobility periods and preference for sucrose was observed to be analogous to imipramine. Diosmin (100 mg/kg) and imipramine substantially quashed CUMS- persuaded escalation of plasma corticosterone and nitrite levels, malondialdehyde levels and MAO-A activity in the brain of stressed mice. Both drugs also substantially reversed CUMS-prompted reduction in catalase activity and brain glutathione levels.

Conclusion:

Accordingly, diosmin revealed significant anti-depressive activity in mice imperiled to chronic mild unpredictable stress paradigm conceivably via mitigation of nitrosative and oxidative stress, reticence of brain MAO-A action, and sink drop of plasma corticosterone degrees.

Targeting autophagy to counteract neuroinflammation: A novel antidepressant strategy

Depression is a common disease that affects physical and mental health and imposes a considerable burden on afflicted individuals and their families worldwide. Depression is associated with a high rate of disability and suicide. It causes a severe decline in productivity and quality of life. Unfortunately, the pathophysiological mechanisms underlying depression have not been fully elucidated, and the risk of its treatment is still presented. Studies have shown that the expression of autophagic markers in the brain and peripheral inflammatory mediators are dysregulated in depression. Autophagy-related genes regulate the level of autophagy and change the inflammatory response in depression. Depression is related to several aspects of immunity. The regulation of the immune system and inflammation by autophagy may lead to the development or deterioration of mental disorders. This review highlights the role of autophagy and neuroinflammation in the pathophysiology of depression, sumaries the autophagy-targeting small moleculars, and discusses a novel therapeutic strategy based on anti-inflammatory mechanisms that target autophagy to treat the disease.

Sequentially Released Liposomes Enhance Anti-Liver Cancer Efficacy of Tetrandrine and Celastrol-Loaded Coix Seed Oil

Background

A sequential release co-delivery system is an effective strategy to improve anti-cancer efficacy. Herein, multicomponent-based liposomes (TET-CTM/L) loaded with tetrandrine (TET) and celastrol (CEL)-loaded coix seed oil microemulsion (CTM) were fabricated, which showed synergistic anti-liver cancer activities. By virtue of Enhanced Permeability and Retention (EPR) effect, TET-CTM/L can achieve efficient accumulation at the tumor site. TET was released initially to repair abnormal vessels and decrease the fibroblasts, and CTM was released subsequently for eradication of tumor tissue.

Methods

TEM (transmission electron microscopy) and DLS (dynamic light scattering) were adopted to characterize the TET-CTM/L. Flow cytometry was adopted to examine the cellular uptake and cytotoxicity of HepG2 cells. The HepG2 xenograft nude mice were adopted to evaluate the anti-tumor efficacy and systemic safety of TET-CTM/L.

Results

TEM images of TET-CTM/L showed the structure of small particle size of CTM within large-size liposomes, indicating that CTM can be encapsulated in liposomes by film dispersion method. In in vitro studies, TET-CTM/L induced massive apoptosis toward HepG2 cells, indicating synergistic cytotoxicity against HepG2 cells. In in vivo studies, TET-CTM/L displayed diminished systemic toxicity compared to celastrol or TET used alone. TET-CTM/L showed the excellent potential for tumor-targeting ability in a biodistribution study.

Conclusion

Our study provides a new strategy for combining anti-cancer therapy that has good potential not only in the treatment of liver cancer but also can be applied to the treatment of other solid tumors.

Tetrandrine attenuates SNI-induced mechanical allodynia by inhibiting spinal CKLF1

Neuropathic pain (NP) is a prevalent clinical problem for which satisfactory treatment options are unavailable. Tetrandrine (TET), a bisbenzylisoquinoline alkaloid extracted from Stephania tetrandra S. Moore, possesses anti-inflammatory and immune-modulatory properties. Chemokine-like factor 1 (CKLF1) is known to play a crucial role in both peripheral and central inflammatory processes. This study aimed to investigate the potential anti-NP effects of TET and the involvement of CKLF1 in the action of TET. A male C57BL/6J mice model of NP caused by spared nerve injury (SNI) was established and mechanical withdrawal thresholds were measured using von Frey filaments. The results showed that TET improved mechanical allodynia in SNI mice and the propofol-induced sleep assay demonstrated that the TET group did not exhibit central inhibition, while the pregabalin (PGB) group showed significant central inhibition. Western blotting and immunofluorescence staining showed that TET significantly inhibited spinal protein expression levels of CKLF1, p-NF-κB/NF-κB, p-IKK/IKK, pro-inflammatory cytokines IL-1β and TNF-α, and increased protein expression levels of the anti-inflammatory cytokine IL-10, while inhibiting the expression levels of microglia and astrocyte markers IBA-1 and GFAP of SNI mice. Moreover, immunofluorescence double-labeling results revealed that CKLF1 was predominantly colocalized with microglia of the spinal cord (SC) in SNI mice. C19 (an antagonism peptide of CKLF1) alleviated SNI-induced mechanical pain hypersensitivity, while C27 (an analog peptide of CKLF1) induced mechanical allodynia in normal mice. TET significantly attenuated mechanical allodynia induced by C27 in mice. TET may effectively alleviate NP by reducing neuroinflammation and decreasing CKLF1.

Exploring the multifocal role of phytoconstituents as antidepressants

Depression is the most prevalent and devastating neuropsychiatric disorder. There are several conventional antidepressants used for the treatment of depression. But due to their undesired adverse effects, patient compliance is very poor. Thus, developing novel medications for the treatment of depression is a critical strategic priority for meeting therapeutic demands. Current research is looking for alternatives to traditional antidepressants to reduce undesired side effects and increase efficacy. Phytoconstituents provide a wide research range in antidepressant treatments. In the present article, we have conducted a comprehensive assessment of neurological evidence, which supports the usefulness of phytoconstituents in the treatment of the depressive disorder. Secondary plant metabolites including alkaloids, polyphenols, glycosides, saponins, and terpenoids were found to exhibit antidepressant action. Most of the phytoconstituents were found to mediate their antidepressant effect through the upregulation of brain-derived neurotrophic factor (BDNF), serotonin, noradrenaline, and dopamine. Some were also found to exert antidepressant effects by inhibiting the monoamine oxidase (MAO) activity and hypothalamic-pituitary-adrenal (HPA) axis overactivity.

Neurotrophic basis to the pathogenesis of depression and phytotherapy

Depression is a major neuropsychiatric disease that considerably impacts individuals’ psychosocial function and life quality. Neurotrophic factors are now connected to the pathogenesis of depression, while the definitive neurotrophic basis remains elusive. Besides, phytotherapy is alternative to conventional antidepressants that may minimize undesirable adverse reactions. Thus, further research into the interaction between neurotrophic factors and depression and phytochemicals that repair neurotrophic factors deficit is highly required. This review highlighted the implication of neurotrophic factors in depression, with a focus on the brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), vascular endothelial growth factor (VEGF), and nerve growth factor (NGF), and detailed the antidepressant activities of various phytochemicals targeting neurotrophic factors. Additionally, we presented future opportunities for novel diagnostic and therapeutic strategies for depression and provided solutions to challenges in this area to accelerate the clinical translation of neurotrophic factors for the treatment of depression.

Effects of Huolisu Oral Solution on Depression-Like Behavior in Rats: Neurotransmitter and HPA Axis

Background: Depression is a common mental disorder, and its morbidity rate is expected to rank second among all mental disorders by 2020. Hence, traditional Chinese medicines gradually attract the attention of many researchers because of their various targets and low toxicity. Huolisu oral solution (HLS) is a Chinese medicine compound preparation, which is present in the Chinese Pharmacopoeia. It is used clinically mainly for the treatment of neurasthenia, perimenopausal syndrome, and insomnia, or depression associated with cerebrovascular disease. Despite the fact that HLS has been used as an antidepressant in clinics, the underlying mechanism is still an untouched domain. To provide a theoretical basis for the clinical application, a series of assessment methods, such as the tail suspension test (TST), forced swim test (FST), and locomotor activity test in mice and rat models of chronic unpredictable mild stress (CUMS), have been conducted in our study.

Objective: The aim of the study was to explore the antidepressive effect and mechanism of HLS.

Methods: CUMS was induced in rats to simulate a depression-like behavior. Neurotransmitters and hormones were detected by enzyme-link immunosorbent assay (ELISA). Pathomorphology examination of the hippocampus was obtained by using the TSView 7 image analysis system. The active ingredients of HLS were also determined by high-performance liquid chromatography (HPLC).

Results: HLS could alleviate the depression-like behavior of the model rats. Biochemical analysis showed that HLS enhanced the levels of 5-hydroxytryptamine (5-HT), norepinephrine (NE), and dopamine (DA) in the hippocampus and diminished these in the serum of the CUMS rats. HLS could also decrease the concentration of corticosterone (CORT), adrenocorticotropic hormone (ACTH), and β-endorphin (β-EP) in blood. The pathohistological examination revealed that the hippocampus and adrenal gland were improved after treatment with HLS.

Conclusions: This study concluded that HLS could alleviate depression-like behaviors in the rats exposed to CUMS, and the potential mechanism may be related to the regulation of the monoamine neurotransmitters, the hypothalamic–pituitary–adrenal (HPA) axis, and the β-EP. These findings hint that HLS is likely to be a potentially effective agent for treating depression.

Natural Products for the Treatment of Post-stroke Depression

Post-stroke depression (PSD) is the most frequent and important neuropsychiatric consequence of stroke. It is strongly associated with exacerbated deterioration of functional recovery, physical and cognitive recoveries, and quality of life. However, its mechanism is remarkably complicated, including the neurotransmitters hypothesis (which consists of a monoaminergic hypothesis and glutamate-mediated excitotoxicity hypothesis), inflammation hypothesis, dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis, and neurotrophic hypothesis and neuroplasticity. So far, the underlying pathogenesis of PSD has not been clearly defined yet. At present, selective serotonin reuptake inhibitors (SSRIs) have been used as the first-line drugs to treat patients with PSD. Additionally, more than SSRIs, a majority of the current antidepressants complied with multiple side effects, which limits their clinical application. Currently, a wide variety of studies revealed the therapeutic potential of natural products in the management of several diseases, especially PSD, with minor side effects. Accordingly, in our present review, we aim to summarize the therapeutic targets of these compounds and their potential role in-clinic therapy for patients with PSD.

Intranasal co-delivery of berberine and evodiamine by self-assembled thermosensitive in-situ hydrogels for improving depressive disorder

The orally administrated antidepressants not only caused side effects such as dizziness, diarrhea, and drug resistance, but also worked slowly. Therefore, new antidepressants and preparations derived from natural medicines play an important role in the study of antidepressant drugs. It was reported that the two components of Zuojin pill, berberine (BBR) and evodiamine (EVO), were used in combination to improve depressive disorder. In our study, a self-assembled thermosensitive in-situ hydrogel was prepared to achieve sustained co-delivery of BBR and EVO. The preparation process of hydrogel consists of two steps, namely, the inclusion of the drugs and thermosensitive self-assembly of the hydrogel. In vitro experimental results indicated that the prepared hydrogel showed a good thermosensitive property under physiological temperature. The hydrogel had a slow and controlled release behavior for BBR and EVO, according with first-order equation. In vivo experimental results indicated that compared to intragastric administration of drug solution, the intranasal administration of hydrogel increased bioavailability of BBR and EVO, approximately 135 and 112 folds, respectively. The hydrogel at a low dose significantly reversed behavioral despair of the mice, improved depressive symptom of rats, and treated depressive disorder by regulating the abnormal levels of monoamine neurotransmitters (including 5-hydroxytryptamine, noradrenalin and dopamine) metabolism and related metabolic pathways such as purine, citrate cycle, scorbate and aldarate, butanoate, vitamin B6, and pyrimidine metabolism. Therefore, as a drug co-delivery system, the intranasally administrated hydrogels with a good release and high bioavailability provides a non-invasive therapeutic strategy for the clinical treatment of depression, which attains antidepressant effects by regulation of the monoamine neurotransmitters metabolism and related metabolic pathways.

Drug Repurposing: An Emerging Tool for Drug Reuse, Recycling and Discovery

Drug repositioning or repurposing is a revolutionary breakthrough in drug development that focuses on rediscovering new uses for old therapeutic agents. Drug repositioning can be defined more precisely as the process of exploring new indications for an already approved drug while drug repurposing includes overall re-development approaches grounded in the identical chemical structure of the active drug moiety as in the original product. The repositioning approach accelerates the drug development process, curtails the cost and risk inherent to drug development. The strategy focuses on the polypharmacology of drugs to unlocks novel opportunities for logically designing more efficient therapeutic agents for unmet medical disorders. Drug repositioning also expresses certain regulatory challenges that hamper its further utilization. The review outlines the eminent role of drug repositioning in new drug discovery, methods to predict the molecular targets of a drug molecule, advantages that the strategy offers to the pharmaceutical industries, explaining how the industrial collaborations with academics can assist in the discovering more repositioning opportunities. The focus of the review is to highlight the latest applications of drug repositioning in various disorders. The review also includes a comparison of old and new therapeutic uses of repurposed drugs, assessing their novel mechanisms of action and pharmacological effects in the management of various disorders. Various restrictions and challenges that repurposed drugs come across during their development and regulatory phases are also highlighted.

Non-clinical toxicity of (+)-limonene epoxide and its physio-pharmacological properties on neurological disorders

The compound (+)-limonene epoxide has antioxidant, anxiolytic, and antihelminthic properties. However, investigations to determine its long-term exposure were not performed. We investigated the systemic toxicological profile after chronic exposure as well as the antidepressant and antiepileptic potentialities of (+)-limonene epoxide on mice. Initially, we evaluated acute toxicity on Artemia salina nauplii and cytotoxicity on mice erythrocytes and peripheral blood mononuclear cells (PBMC). Aftterwards, mice were chronically treated for 120 days by gavage with (+)-limonene epoxide (25, 50, and 75 mg/kg/day) and this exposure was assessed by pathophysiological measurements. For antidepressant and anticonvulsivant analysis, we performed the forced swimming and tail suspension protocols and pentylenetetrazol- and picrotoxin-induced seizures, respectively. (+)-Limonene epoxide showed a LC50 value of 318.7 μg/mL on A. salina shrimps, caused lysis of red blood cells at higher concentrations only but did not show cytotoxicity on PMBC, which suggests pharmacological safety if plasma concentrations do not exceed 100 μg/mL. Macroscopic, hematological, clinical chemistry, and nutritional changes were not detected, though focal areas of hepatic necrosis, inflammatory infiltrate, and karyolysis have been detected at 75 mg/kg/day. The compound inhibited the developing of pentylenetetrazol- and picrotoxin-induced seizures, decreased deaths, and reduced immobility times, mainly at 75 mg/kg. So, it reversed reserpine effects, suggesting antidepressant effects should be linked to serotonergic and/or adrenergic transmission. It is feasible that (+)-limonene epoxide plays a benzodiazepine-like anticonvulsive action and may be also recommended as an antidote for poisonings caused by central depressants.

Tetrandrine: a review of its anticancer potentials, clinical settings, pharmacokinetics and drug delivery systems

OBJECTIVES

Tetrandrine, a natural bisbenzylisoquinoline alkaloid, possesses promising anticancer activities on diverse tumours. This review provides systematically organized information on cancers of tetrandrine in vivo and in vitro, discuss the related molecular mechanisms and put forward some new insights for the future investigations.

KEY FINDINGS

Anticancer activities of tetrandrine have been reported comprehensively, including lung cancer, colon cancer, bladder cancer, prostate cancer, ovarian cancer, gastric cancer, breast cancer, pancreatic cancer, cervical cancer and liver cancer. The potential molecular mechanisms corresponding to the anticancer activities of tetrandrine might be related to induce cancer cell apoptosis, autophagy and cell cycle arrest, inhibit cell proliferation, migration and invasion, ameliorate metastasis and suppress tumour cell growth. Pharmaceutical applications of tetrandrine combined with nanoparticle delivery system including liposomes, microspheres and nanoparticles with better therapeutic efficiency have been designed and applied encapsulate tetrandrine to enhance its stability and efficacy in cancer treatment.

SUMMARY

Tetrandrine was proven to have definite antitumour activities. However, the safety, bioavailability and pharmacokinetic parameter studies on tetrandrine are very limited in animal models, especially in clinical settings. Our present review on anticancer potentials of tetrandrine would be necessary and highly beneficial for providing guidelines and directions for further research of tetrandrine.

Potential effect of herbal antidepressants on cognitive deficit: Pharmacological activity and possible molecular mechanism

ETHNOPHARMACOLOGICAL RELEVANCE

Cognitive symptom is a "core" symptom of major depressive disorder (MDD) patients with clear deficit in memory, social and occupational function, and may persist during the remitting phase. Therefore, the remission of cognitive symptom has been considered as one of the main objectives in the treatment of MDD. Herbal antidepressants have been used to treat MDD, and there has been great advances in the understanding of the ability of these herbs to improve cognitive deficit linked to brain injury and various diseases including depression, Alzheimer disease, diabetes and age-related disorders. This systematic review summarizes the evidence from preclinical studies and clinical trials of herbal antidepressants with positive effects on cognitive deficit. The potential mechanisms by which herbal antidepressants prevent cognitive deficit are also reviewed. This review will facilitate further research and applications.

MATERIALS AND METHODS

We conducted an open-ended, English restricted search of MEDLINE (PubMed), Web of Science and Scopus for all available articles published or online before 31 December 2019, using terms pertaining to medical herb/phytomedicine/phytochemical/Chinese medicine and depression/major depressive disorder/antidepressant and/or cognitive impairment/cognitive deficit/cognitive dysfunction.

RESULTS

7 prescriptions, more than 30 individual herbs and 50 phytochemicals from China, Japan, Korea and India with positive effects on the depressive state and cognitive deficit are reviewed herein. The evidence from preclinical studies and clinical trials proves that these herbal antidepressants exhibit positive effects on one or more aspects of cognitive defect including spatial, episodic, aversive, and short- and long-term memory. The action mode of the improvement of cognitive deficit by these herbal antidepressants is mediated mainly through two pathways. One pathway is to promote hippocampal neurogenesis through activating brain derived neurotrophic factor-tropomyosin-related kinase B signaling. The other pathway is to prevent neuronal apoptosis through the inhibition of neuro-inflammation and neuro-oxidation.

CONCLUSION

These herbal antidepressants, having potential therapy for cognitive deficit, may prevent pathological processes of neurodegenerative diseases. Furthermore, these herbal medicines should provide a treasure trove, which will accelerate the development of new antidepressants that can effectively improve cognitive symptom in MDD. Studies on their molecular mechanisms may provide more potential targets and therapeutic approaches for new drug discovery.

Intranasal delivery of icariin via a nanogel-thermoresponsive hydrogel compound system to improve its antidepressant-like activity

Although icariin has been reported to have antidepressant-like effects in different animal models, its poor oral bioavailability and low efficiency of delivery to the brain limit its application. In this study, icariin nanogels were prepared by reverse microemulsion methods to improve its poor water solubility. Then, we developed an icariin nanogel loaded self-assembled thermosensitive hydrogel system (icariin-NGSTH) to deliver icariin via a noninvasive, direct nose-to-brain delivery route for the treatment of depression. The in vivo distribution was investigated by fluorescence imaging with rhodamine B-labeled nanogels. The antidepressant efficacy of icariin-NGSTH was evaluated in behavioral despair tests and the chronic unpredictable mild stress (CUMS) model. The results showed that icariin-NGSTH had a zero-order kinetics release in the first 10 h. Icariin-NGSTH led to rapid brain distribution within 30 min. Icariin-NGSTH significantly reduced the duration of immobility in the tail suspension test (TST) and forced swim test (FST). Compared with oral administration, intranasally administered icariin-NGSTH had a fast-acting antidepressant effect in the TST and FST. Moreover, icariin-NGSTH increased body weight and sucrose preference, reversed abnormal plasma levels of testosterone, interleukin-6 (IL-6) and prostaglandin E₂ (PGE₂), and repaired neuronal damage in the hippocampi of CUMS rats. These results indicated that icariin-NGSTH at a low dose produced a significant antidepressant effect. As a complex drug delivery system, intranasally administered icariin-NGSTH is a rapid and effective treatment for depression, increasing the antidepressant-like activity of icariin.

Traditional Chinese Medicine in Depression Treatment: From Molecules to Systems

Depression is a multigenetic or multifactorial syndrome. The central neuron system (CNS)-orientated, single target, and conventional antidepressants are insufficient and far from ideal. Traditional Chinese Medicine (TCM) has historically been used to treat depression up till today, particularly in Asia. Its holistic, multidrug, multitarget nature fits well with the therapeutic idea of systems medicine in depression treatment. Over the past two decades, although efforts have been made to understand TCM herbal antidepressants at the molecular level, many fundamental questions regarding their mechanisms of action remain to be addressed at the systems level in order to better understand the complicated herbal formulations in depression treatment. In this Mini Review, we review and discuss the mechanisms of action of herbal antidepressants and their acting targets in the pathological systems in the brain, such as monoamine neurotransmissions, hypothalamic–pituitary–adrenal (HPA) axis, neurotropic factor brain-derived neurotrophic factor (BDNF) cascade, and glutamate transmission. Some herbal molecules, constituents, and formulas are highlighted as examples to discuss their mechanisms of action and future directions for comprehensive researches at the systems level. Furthermore, we discuss pharmacological approaches to integrate the mechanism of action from the molecular level into the systems level for understanding of systems pharmacology of TCM formulations. Integration of the studies at the molecular level into the systems level not only represents a trend in TCM study but also promotes our understanding of the system-wide mechanism of action of herbal antidepressant formulations.

Neuroplasticity-related mechanisms underlying the antidepressant-like effects of traditional herbal medicines

Traditional herbal medicine can offer efficacious and safe alternative pharmacotherapies for depression. The ability of an herbal medicine to produce neuroadaptive processes, that enhance neuroplasticity and cellular resilience in response to chronic stress, may point to its antidepressant potential. We suggest that among many investigated herbal medicines, those that can enhance neuroplasticity may have stronger therapeutic potential. The current article presents a summary of traditional herbal medicines, which are thought to exert antidepressant-like effects in chronic stress models via neuroplasticity enhancement. Brain-derived neurotrophic factor (BDNF) is a biomarker for neuroplasticity-related mechanisms compromised in depression and recovered by conventional antidepressants, including synaptic plasticity, cell survival, neurogenesis and spine formation. We therefore presumed that if an herbal medicine up-regulates BDNF in the hippocampus and/or prefrontal cortex (PFC), its antidepressant-like effect is mediated, at least partially, via neuroplasticity-related mechanisms. Literature search was performed using the general terms depression, stress, neuroplasticity and herbal medicines. Screening of retrieved preclinical studies revealed 30 traditional herbal medicines: 8 single herbs, 15 bioactive constituents, and 7 herbal formulas. The antidepressant-like effects of these medicines were associated with reversal of chronic stress-induced impairment in neuroplasticity, most notably by BDNF up-regulation, activation of BDNF downstream signaling pathways and increase in neurogenesis in the hippocampus and/or PFC/frontal cortex. In light of the ability of these medicines to enhance neuroplasticity, we suggest that they may be suitable candidates for clinical investigation in depressed individuals. Once their efficacy, tolerability and safety will be substantiated, they may serve as natural alternatives to conventional antidepressants.

Antidepressant-like effects of Marasmius androsaceus metabolic exopolysaccharides on chronic unpredictable mild stress-induced rat model

Marasmius androsaceus (M. androsaceus), a medicinal fungus, has various pharmacological activities including antidepression. The present study investigated the effects of exopolysaccharides obtained during M. androsaceus submerged fermentation in a chronic unpredictable mild stress (CUMS)‑induced depression rat model. Similar to fluoxetine (positive drug), 4‑week administration of M. androsaceus exopolysaccharides (MEPS) at doses of 6, 30 and 150 mg/kg strongly enhanced bodyweight gain and sucrose consumption, and reduced the immobility time in forced swimming test and tail suspension test in CUMS rats. MEPS resulted in significant enhancement on the levels of noradrenalin, dopamine, 5‑hydroxytryptamine (5‑HT), and 5‑hydroxyindoleacetic acid in the serum and hypothalamus of CUMS rats, as detected by ELISA. Western blotting results revealed that MEPS upregulated the protein expression levels of tyrosine hydroxylase in the hypothalamus of CUMS rats. In conclusion, these results confirmed the antidepressant‑like effects of MEPS, and suggested that the monoamine neurotransmitter system is involved in its antidepressive effects in a CUMS rat model. The present study provided evidence for the clinical application of MEPS as an effective agent against depression.

Mental Health Comorbidities in Pediatric Chronic Pain: A Narrative Review of Epidemiology, Models, Neurobiological Mechanisms and Treatment

Chronic pain during childhood and adolescence can lead to persistent pain problems and mental health disorders into adulthood. Posttraumatic stress disorders and depressive and anxiety disorders are mental health conditions that co-occur at high rates in both adolescent and adult samples, and are linked to heightened impairment and disability. Comorbid chronic pain and psychopathology has been explained by the presence of shared neurobiology and mutually maintaining cognitive-affective and behavioral factors that lead to the development and/or maintenance of both conditions. Particularly within the pediatric chronic pain population, these factors are embedded within the broader context of the parent-child relationship. In this review, we will explore the epidemiology of, and current working models explaining, these comorbidities. Particular emphasis will be made on shared neurobiological mechanisms, given that the majority of previous research to date has centered on cognitive, affective, and behavioral mechanisms. Parental contributions to co-occurring chronic pain and psychopathology in childhood and adolescence will be discussed. Moreover, we will review current treatment recommendations and future directions for both research and practice. We argue that the integration of biological and behavioral approaches will be critical to sufficiently address why these comorbidities exist and how they can best be targeted in treatment.

The Antidepressant Effect of Angelica sinensis Extracts on Chronic Unpredictable Mild Stress-Induced Depression Is Mediated via the Upregulation of the BDNF Signaling Pathway in Rats

Angelica sinensis (AS), a traditional Chinese herbal medicine, has pharmaceutical effects on menstrual illness, cerebrovascular diseases, cardiovascular diseases, and cognitive impairments. However, until recently, few studies had explored its antidepressant effect. The current study attempts to investigate the effect of AS extracts on chronic unpredictable mild stress- (CUMS-) induced depression in rats. Male SD rats were exposed to a CUMS-inducing procedure for 5 weeks, resulting in rodent depressive behaviors that included reduced sucrose consumption and lessened sucrose preference ratios in sucrose preference test, prolonged immobility times and decreased struggling time in force swim test, and decreased locomotor activity in open field test. Moreover, the expression of brain derived neurotrophic factor (BDNF) and the phosphorylation of cAMP-response element binding protein (CREB) and extracellular signal-regulated protein kinase (ERK 1/2) were markedly decreased in the hippocampus in depressed rats. However, chronically treating the depressed rats with AS (1 g/kg) normalized their depression-related behaviors and molecular profiles. In conclusion, in the present study, we show that AS extracts exerted antidepressant effects that were mediated by the BDNF signaling pathway: in AS-treated depressed rats, the expression of the BDNF protein and the phosphorylation of its downstream targets (ERK 1/2, CREB) were upregulated in the hippocampus.

Antidepressant-like effects of albiflorin extracted from Radix paeoniae Alba

ETHNOPHARMACOLOGY RELEVANCE

Albiflorin, a monoterpene glycoside, is a main component of Radix paeoniae Alba, which could be a Chinese herbal medicine used in the treatment of psychiatric disorders. However, the exact role of albiflorin in depression is poorly understood.

AIM OF THE STUDY

The current study aimed to evaluate the antidepressant effect of albiflorin in mice and rats, and the possible mechanism was also determined.

MATERIALS AND METHODS

The antidepressant-like effects of albiflorin was determined by using animal models of depression including forced swim and tail suspension tests in mice and chronic unpredictable stress (CUS) in rats. The acting mechanism was explored by determining the effect of albiflorin on the expression of brain-derived neurotrophic factor (BDNF) in the hippocampus by western blot and the levels of monoamine in the hippocampus by HPLC.

RESULTS

Our results showed that 7 days treatment with albiflorin significantly decreased immobility time in the forced swimming test (FST) and the tail suspension test (TST) at doses of 3.5, 7.0 and 14.0mg/kg without alter the locomotor activity in mice. Moreover, western blot analysis showed that albiflorin could increase the expression of BDNF in the hippocampus. We further exposed rats to a chronic unpredictable stress (CUS) protocol for a period of 35d to induce depressive-like behaviors. We found that chronic treatment with albiflorin, at doses of 7.0 and 14.0mg (i.g., once daily for 35d), restored the sucrose preference in CUS rats. In the open-field test, albiflorin significantly increased the number of crossings and rearings in the CUS rats at three doses. Moreover, chronic treatment with albiflorin up-regulated the hippocampal BDNF expression levels and the hippocampal 5-HT, 5-HIAA, and NA levels.

CONCLUSION

Albiflorin produced significant antidepressant-like effects, which were closely related to the hippocampal 5-HT/NE increase and BDNF expression. Our data indicated that albiflorin could be a potential anti-depressant drug.

The influence of dizocilpine on the reserpine-induced behavioral and neurobiological changes in rats

Clinical studies have demonstrated that a single dose of ketamine produces complete remission within 24h in some depression patients. The ability of ketamine to produce fast-acting antidepressant-like effects in animal models depends on rapid synthesis of brain-derived neurotrophic factor (BDNF). Here we examined effects of a single dose dizocilpine, a non-competitive NMDA receptor antagonist, on the behavioral and neurobiological changes in rats treated with a single high dose reserpine, which is a monoamine re-uptake blocker and depletes monoamines in the brain with the outcome of depression-like symptoms in animals. A single high dose reserpine (4.0mg/kg) was given to rats intraperitoneally. Forty-eight hours later, the rats showed depressive symptoms as evidenced by decreased locomotor activity in the open field and increased immobility time in the forced swim test. Meanwhile, the treatment decreased BDNF levels and neurogenesis in the hippocampus. Pretreatment of a single dose dizocilpine (0.30mg/kg), however, prevented all the reserpine-induced changes, except for GluN1 subunit. These results are suggestive of the involvement of neurogenesis and BDNF in the rapid-acting antidepressant-like behavioral effects of the NMDA receptor antagonists in the reserpinized rats.

Investigation of the antidepressant effects of exopolysaccharides obtained from Marasmius androsaceus fermentation in a mouse model

Marasmius androsaceus, a well‑known medical fungus, possesses antihypertensive, analgesic and antioxidant effects. Exopolysaccharide (EPS), produced by microorganism secretion, exerts various types of biological activities. The present study aimed to investigate the antidepressant‑like effect of the EPS produced during Marasmius androsaceus submerge fermentation (MEPS). Based on the assessment of acute toxicity and behavior, a forced swimming test (FST), tail suspension test (TST), 5‑hydroxytryptophan‑induced head‑twitch assessment and reserpine‑induced hypothermia assessment were performed. The administration of MEPS for 7 days enhanced mouse locomotor and balance ability in the mice. Similar to the results following treatment with fluoxetine, which was used as positive control drug, MEPS significantly decreased the duration of immobility in the FST and TST, increased head twitches in the 5‑HTP‑induced head‑twitch test and enhanced rectal temperature in resperpine‑induced hypothermia. MEPS altered the abnormal concentrations of 5‑hydroxytryptamine, 5‑hydroxyindoleacetic acid, dopamine and norepinephrine in the hypothalamus in the resperine‑induced mouse model. Additionally, an increase in the expression of tyrosine hydroxylase and a reduction in the level of dopamine transporter in the hypothalamus were noted following 7 days of MEPS administration. Taken together, the EPS produced during MEPS exhibited antidepressant‑like effects, which may be associated with its regulation on the dopaminergic system. The results of the present study provide experimental evidence supporting the clinical use of MEPS as an effective agent against depression.

The Functional Study of a Chinese Herbal Compounded Antidepressant Medicine--Jie Yu Chu Fan Capsule on Chronic Unpredictable Mild Stress Mouse Model

Jie Yu Chu Fan capsule (JYCF) is a new compounded Chinese herbal medicine for the treatment of depression. The present study was designed to explore the antidepressant effects and the possible mechanisms of JYCF by using chronic unpredictable mild stress (CUMS) mouse model and comparing results to that of fluoxetine. Behavioral tests including an open field test, sucrose preference test and forced swim test were performed to evaluate the antidepressant effects of JYCF. The concentrations of monoamine neurotransmitters and metabolic products including norepinephrine (NE), 5-hydroxytryptamine (5-HT), dopamine (DA), 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC) in the cerebral cortex and hippocampus of mice were determined by means of high performance liquid chromatography with electrochemical detection (HPLC-EC). The results show that a successful mouse CUMS model was established through 5 weeks of continuous unpredictable stimulation, as indicated by the significant decrease in sucrose preference and locomotor activity and increase in immobility time in the forced swim test. Chronic treatment of JYCF (1.25, 2.5 and 5 g/kg) and fluoxetine (20mg/kg) significantly reversed the CUMS-induced behavioral abnormalities. JYCF (1.25, 2.5 and 5 g/kg) significantly increased NE in CUMS mouse prefrontal cortex (P < 0.01, P < 0.01, P < 0.05 respectively) and 5-HT in hippocampus (P < 0.05). In summary, our findings suggest that JYCF exerts comparable antidepressant-like effects to that of fluoxetine in CUMS mice. Besides, the antidepressant-like effect of JYCF is mediated by the increase of monoaminergic transmitters including 5-HT and NE.

Tetrandrine protects mouse retinal ganglion cells from ischemic injury

This study aimed to determine the protective effects of tetrandrine (Tet) on murine ischemia-injured retinal ganglion cells (RGCs). For this, we used serum deprivation cell model, glutamate and hydrogen peroxide (H₂O₂)-induced RGC-5 cell death models, and staurosporine-differentiated neuron-like RGC-5 in vitro. We also investigated cell survival of purified primary-cultured RGCs treated with Tet. An in vivo retinal ischemia/reperfusion model was used to examine RGC survival after Tet administration 1 day before ischemia. We found that Tet affected RGC-5 survival in a dose- and time-dependent manner. Compared to dimethyl sulfoxide treatment, Tet increased the numbers of RGC-5 cells by 30% at 72 hours. After 48 hours, Tet protected staurosporine-induced RGC-5 cells from serum deprivation-induced cell death and significantly increased the relative number of cells cultured with 1 mM H₂O₂ (P<0.01). Several concentrations of Tet significantly prevented 25-mM-glutamate-induced cell death in a dose-dependent manner. Tet also increased primary RGC survival after 72 and 96 hours. Tet administration (10 μM, 2 μL) 1 day before retinal ischemia showed RGC layer loss (greater survival), which was less than those in groups with phosphate-buffered saline intravitreal injection plus ischemia in the central (P=0.005, n=6), middle (P=0.018, n=6), and peripheral (P=0.017, n=6) parts of the retina. Thus, Tet conferred protective effects on serum deprivation models of staurosporine-differentiated neuron-like RGC-5 cells and primary cultured murine RGCs. Furthermore, Tet showed greater in vivo protective effects on RGCs 1 day after ischemia. Tet and ciliary neurotrophic factor maintained the mitochondrial transmembrane potential (ΔΨm) of primary cultured RGCs and inhibited the expression of activated caspase-3 and bcl-2 in ischemia/reperfusion-insult retinas.