Not only serotonergic system, but also dopaminergic system involved in albiflorin against chronic unpredictable mild stress-induced depression-like behavior in rats

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.

Albiflorin Attenuates Neuroinflammation and Improves Functional Recovery After Spinal Cord Injury Through Regulating LSD1-Mediated Microglial Activation and Ferroptosis

Spinal cord injury (SCI) is a serious, prolonged, and irreversible injury with few therapeutic options. Albiflorin (AF) possesses powerful pharmacodynamic properties and exerts protective effects against neuroinflammation. However, no research has examined the neuroprotective effect of AF following SCI. Rats were received laminectomy to establish SCI animal model and treated with AF (20 mg/kg and 40 mg/kg). Behavioral experiments were conducted to assess the impacts of AF on motor function after SCI in rats. Hematoxylin-eosin (HE) staining, Nissl staining, and Prussian Blue staining were performed to observe histological changes, neuronal damage, and iron deposition, respectively. Transmission electron microscope was adopted to observe the ultrastructure of spinal cord tissues. Immunofluorescence assay was performed to examine neurons and microglia. ELISA assay was used to examine the production of cytokines. Western blot assay was used to detect the expression level of ferroptosis-related proteins. Microglia BV-2 cells were induced by LPS to mimic the neuroinflammatory condition. Cell viability was assessed by CCK-8 assay, and lipid peroxidase level was measured by C11 BODIPY 581/591 staining. Molecular docking technology was utilized to confirm the relationship between AF and LSD1. AF improved the motor functional recovery after SCI in rats. Meanwhile, AF attenuated neuron apoptosis and microglia activation, reduced the production of pro-inflammatory cytokines and iron accumulation, and inhibited spinal cord ferroptosis following SCI in rats. LSD1 was verified to be a target protein of AF, and AF could concentration-dependently downregulate LSD1 expression in injured spinal cords in vivo and LPS-induced BV-2 cells in vitro. In addition, AF not only inhibited ferroptosis through reducing lipid peroxidase and iron levels and regulating ferroptosis-related proteins, but also inhibited microglial activation and reduced pro-inflammatory cytokines production in LPS-induced BV-2 cells; however, these changes were partly counteracted by LSD1 overexpression. AF could reduce microglial activation and ferroptosis, attenuate neuroinflammation, and improve functional recovery following SCI by downregulating LSD1, providing novel therapeutic strategies for the treatment of SCI.

Escitalopram reversibility of the impacts following chronic stress on central 5-HT profiles - Implications to depression and anxiety

Stress is considered a crucial determinant influencing health capacity in modern society. Long-term stress makes individuals more susceptible to mental dysfunctions, among which depression and anxiety are two major mental disorders. The success of using selective serotonin reuptake inhibitors (SSRIs) to treat these two disorders highlights the involvement of the central serotonergic (5-HT) system. Later studies suggest both presynaptic and postsynaptic 5-HT profiles should be considered for the effects of SSRIs, making it difficult to interpret the etiological and therapeutic mechanisms underlying depression and anxiety. The present study aims to examine whether the intervention of escitalopram (Es, 5 mg/kg daily for 14 days) can reverse the behavioral phenotypes of both depression-like [by sucrose preference test (SPT) and forced swim test (FST)] and anxiety-like [by avoidance latency and escape latency in elevated-T maze (ETM)] behaviors, and the brain area-dependent neurochemical changes of 5-HT profiles of the terminal regions regarding both synaptic efflux and tissue levels in rats of chronic mild stress (CMS). Our results showed that: (i) Even mild stresses when presented in an unpredictable and long-term manner, can induce both depression-like and anxiety-like behaviors. (ii) Depressive profile indexed by SPT was more sensitive to reflect the Es effect than that of FST. (iii) Es did not significantly affect the CMS-induced anxiety-like symptoms indexed by ETM. (iv) Changes in the protein expression of 5-HT1A receptors in the prefrontal cortex and hippocampus were compatible with the treatment outcome. Our results contributed to the understanding of stress-induced mood dysfunction and the involvement of central 5-HT.

Augmentation therapy with tandospirone citrate in vascular depression patients with mild cognitive impairment: A prospective randomized clinical trial

Cognitive impairment is a prominent clinical manifestation of vascular depression (VaDep). The current study aimed to assess the efficacy of tandospirone citrate in VaDep cases with mild cognitive impairment (VaDep-MCI) as well as the role of plasma monoamine neurotransmitters during the treatment. In this single-blind, randomized controlled study, 116 participants were randomly assigned to the tandospirone (tandospirone citrate-escitalopram) and control (escitalopram) groups. The primary endpoints were changes in cognitive test scores from baseline to Week 8, including the Rey Auditory Verbal Learning Test (RAVLT), Semantic Verbal Fluency (SVF) test, Trail Making Test (TMT), Digital Span Test (DST) and Clock Drawing Test (CDT) scores. Generalized estimating equation models were used to examine repeated measures. The results showed that compared with the changes in the control group from baseline to Week 8, the tandospirone group showed more significant changes in SVF score at Weeks 4 (p < 0.05) and 8 (p < 0.001), and TMT (B-A) score at Week 8 (p < 0.05). RAVLT, DST and DCT scores were relatively stable in both groups during the study period. Moreover, mediation analysis showed that these results were not mediated by the alleviation of depression symptoms. Partial Spearman correlation analysis showed that only plasma 5-hydroxytryptamine (5-HT) was positively correlated with Hamilton Depression Rating Scale score after Bonferroni correction (r = 0.347, p < 0.001). Augmentation therapy with tandospirone citrate improved the executive and language functions of VaDep-MCI patients. Additionally, plasma 5-HT levels may serve as a potential biomarker of VaDep severity. These findings may provide clinical insights into the treatment of vascular depression.

Antidepressant effects of the traditional Chinese herbal formula Xiao-Yao-San and its bioactive ingredients

BACKGROUND

Depression is one of the most debilitating and severe psychiatric disorders and a serious public health concern. Currently, many treatments are indicated for depression, including traditional Chinese medicinal formulae such as Xiao-Yao-San (XYS), which has effective antidepressant effects in clinical and animal studies.

PURPOSE

To summarize current evidence of XYS in terms of the preclinical and clinical studies and to identify the multi-level, multi-approach, and multi-target potential antidepressant mechanisms of XYS and active components of XYS by a comprehensive search of the related electronic databases.

METHODS

The following electronic databases were searched from the beginning to April 2022: PubMed, MEDLINE, Web of Science, Google Scholar, and China National Knowledge Infrastructure.

RESULTS

This review summarizes the antidepressant mechanisms of XYS and its active ingredients, which are reportedly correlated with monoamine neurotransmitter regulation, synaptic plasticity, and hypothalamic-pituitary-adrenal axis, etc. CONCLUSION: XYS plays a critical role in the treatment of depression by the regulation of several factors, including the monoaminergic systems, hypothalamic-pituitary-adrenal axis, synaptic plasticity, inflammation, brain-derived neurotrophic factor levels, brain-gut axis, and other pathways. However, more clinical and animal studies should be conducted to further investigate the antidepressant function of XYS and provide more evidence and recommendations for its clinical application. Our review provides an overview of XYS and guidance for future research direction.

Antidepressive-Like Effect of Aegle marmelos Leaf Extract in Chronic Unpredictable Mild Stress-Induced Depression-Like Behaviour in Rats

Background

Depression is a psychiatric disorder leading to anhedonia and lack of interest and motivation. Depressive symptoms are triggered by stressful life events, and patients with major depression are at significantly increased risk of attempting suicide. The crucial concern in depression treatment with antidepressant medications is that few weeks are required to show the therapeutic effect along with moderate side effects. The use of herbal medications is a new strategy for the treatment of depression which is often based on medicinal plants.Aegle marmelos (L.) Corr. (family: Rutaceae) is reported to have several actions on the central nervous system producing beneficial effects in anxiety, Alzheimer's disease, Parkinson's disease, epilepsy, and convulsion. Thus, the current investigation designed to assess the antidepressant activity of the standardized hydroethanolic extract of Aegle marmelos (EAM) leaves in male rats exposed to the chronic unpredictable mild stress (CUMS) paradigm.

Methods

Rats were divided in 5 groups. The control group was not subjected to experimental CUMS paradigm, while 4 other groups were subjected to CUMS paradigm to induce depression-like behaviour from day 1 to day 28. Following the CUMS paradigm, 4 groups were divided as CUMS disease control, CUMS+EAM (150 mg/kg, p.o.), CUMS+EAM (300 mg/kg, p.o.), and CUMS+imipramine (15 mg/kg, p.o.), and treatment was given for seven consecutive days to the respective groups (day 29 to day 35). Behavioural parameters such as open field test, forced swim test, sucrose feeding test, and tail suspension test on day 1, day 28, and day 35 were measured, and biochemical parameters such as plasma corticosterone level, serotonergic system (5-HT, 5-HIAA, and 5-HT/5-HIAA), mitochondrial function, and proinflammatory mediators (TNF-α, IL-1β, and IL-6) were estimated in hippocampus (HIP) and prefrontal cortex (PFC) regions of the brain on day 35, after the behavioural observations. On the other hand, phytochemical profile of Aegle marmelos was done.

Results

On day 35, EAM (300 mg/kg) significantly reduced the immobility time during the tail suspension test from 208.66 ± 4.72 s to 108.83 ± 4.81 s and forced swim test from 200.16 ± 4.12 s to 148.5 ± 4.58 s. It also enhanced the behavioural parameters in the open field test such as ambulation from 26.5 ± 2.14 to 56.5 ± 1.80, rearing from 8.33 ± 0.71 to 19 ± 0.57, time spent in centre from 9.16 ± 0.9 to 17.16 ± 0.79 s, total distance travelled from 2.36 ± 0.12 to 4.68 ± 0.10 m, and anhedonia in the sucrose feeding test from 109.33 ± 1.08 to 135.83 ± 3.91 mL. The stimulation of the HPA axis resulting elevated corticosterone level caused by CUMS was reduced by EAM (300 mg/kg) from 80.12 ± 2.020 to 48.25 ± 2.407 μg/dL. Furthermore, EAM (300 mg/kg) increase CUMS-induced changes in serotonin (5-HT) level in HIP and PFC from 3.132 ± 0.09586 to 4.518 ± 0.1812 and 4.308 ± 0.1593 to 5.262 ± 0.1014 ng/mg protein, respectively. EAM (300 mg/kg) significantly attenuated the CUMS-induced changes in proinflammatory cytokine production and mitochondrial function in HIP and PFC. One group used to determine the acute toxicity as per OECD-23 standard protocol which resulted that 300 mg/kg EAM has no significant acute toxicity. Total phenolic content and total flavonoid content of standardized hydroalcoholic extract of AM was found 95.024 ± 2.431 and 36.820 ± 3.41, respectively, and additional identification tests showed the presence of alkaloids, tannins, saponins, cardiac glycosides, flavonoids, and terpenoids.

Conclusion

On the basis of findings, EAM can be inferred as a potential antidepressant-like effect of this plan in preclinical research.

The modulatory effects of alkaloid extracts of Cannabis sativa, Datura stramonium, Nicotiana tabacum and male Carica papaya on neurotransmitter, neurotrophic and neuroinflammatory systems linked to anxiety and depression

This study investigated the modulatory effects of alkaloid extracts of Cannabis sativa (CSAE), Datura stramonium (DSAE), Nicotiana tabacum (NTAE) and male Carica papaya (CMAE) on neurotransmitter, neurotrophic and neuro-inflammatory systems linked to anxiety and depression. Male Wistar rats were orally administered the alkaloid extracts in doses of 5, 50, 500, and 2000 mg/kg for 90 days. On day 91, neurobehavioural studies were evaluated, rats were sacrificed, brain hippocampus removed and tissue homogenate prepared. Biochemical, cytokine and neurotransmitter metabolisms were estimated in the hippocampus. Expressions of genes linked to anxiety and depression were evaluated by RT-qPCR. Results showed CSAE, NTAE and CMAE act as anxiolytic and antidepressant agents by depleting TNF-α, IL-1β and reactive oxygen species concentrations, and monoamine oxidase, angiotensin 1-converting enzyme and acetylcholinesterase activities while elevating IL-10 and dopamine concentrations and glutamate dehydrogenase activity at doses of 5, 50 and 500. Same doses of CSAE, NTAE and CMAE also depleted the gene expressions of GSK3β, JNK, NF-ĸB, and Nesfatin-1 while increasing expressions of CREB, BDNF, serotonin and Nrf2. However, administration of DSAE and 2000 mg/kg CSAE, NTAE and CMAE had adverse modulatory effects on the neurochemical concentrations and activities as well as the gene expressions of the evaluated neurotransmitter, neurotrophic and inflammatory systems. In conclusion, the study established the sub-chronic instrumentalization potential of CSAE, CMAE, and NTAE for anxiolytic and anti-depressive moods, though their use may be associated with dependence and addiction, which may result in more detrimental effects than any therapeutic potential they may proffer.

Phytochemical identification of Xiaoer Huanglong Granule and pharmacokinetic study in the rat using its seven major bioactive components

Xiaoer Huanglong Granule is the only Chinese Patent Medicine widely used for treating attention deficit hyperactivity disorder. However, not much is known on the bioactive components and pharmacokinetics of Xiaoer Huanglong Granule even after it was successfully introduced into clinical use. This study analyzed the components in the medication and rat plasma after oral administration with the help of UNIFI platform and Masslynx. A total of 119 and 37 components were detected in the medication and plasma, respectively, using ultra performance liquid chromatography - tandem mass spectrometer. We established a rapid and sensitive simultaneous determination of 1 triterpene saponin, 3 monoterpene glycosides, and 3 lignans in rat plasma by solid-phase extraction. The determination was accomplished within 7.50 min via gradient elution. The values of lower limit of quantification were validated at 0.08 ng/mL for tenuifolin, 0.8 ng/mL for lactiflorin, 1.828 ng/mL for albiflorin, 2 ng/mL for paeoniflorin, gomisin B, and gomisin D, 10 ng/mL for schisandrin. The results from validations of other methods were all acceptable (RSD ≤ 14.94%). This is the first report on the identification and pharmacokinetics studies of components in Xiaoer Huanglong Granule. Moreover, the pharmacokinetic behavior of lactiflorin was studied for the first time. This article is protected by copyright. All rights reserved.

Alginate nanogels-based thermosensitive hydrogel to improve antidepressant-like effects of albiflorin via intranasal delivery

Depression is a primary public health problem. However, current antidepressants work slowly, and together with side effects. Herein, the alginate nanogels were constructed to load albiflorin (albiflorin nanogels), which further formed albiflorin nanogel loaded self-assembled thermosensitive hydrogel system (albiflorin-NGSTH) and were used to improve its antidepressant effects. The nanogel showed a nano-scaled particle size and stronger antioxidant activity. Rheological studies showed that albiflorin-NGSTH had a sol-gel transition at approximately 28 °C. Albiflorin-NGSTH quickly entered the brain by intranasal delivery, and had a continuously release for albiflorin. Preliminary results of mice behavioral despair tests found that albiflorin-NGSTH had no effects on independent exploratory behavior and anxiety of the mice, and significantly decreased immobility duration of the mice in tail suspension test (TST). Moreover, the intranasally administrated albiflorin-NGSTH at a low dose improved depressive behavior, decreased levels of proinflammatory cytokines, and repaired neuronal damage of chronic unpredictable mild stress (CUMS) rats, which indicated an excellent potential for depression therapy. The treatment of albiflorin-NGSTH on depressive disorder was achieved by regulating signal pathway related to depression. Therefore, albiflorin-NGSTH has an excellent potential for clinical application in intranasal drug delivery systems.

Antidepressant-like effects of albiflorin involved the NO signaling pathway in rats model of chronic restraint stress

The depressant-like effects of albiflorin (AF) were studied on stressed chronic restraint stress (CRS) rats. Experimental rats were subjected to immobilization stress for a daily 6 h-restraining in a plastic restrainer for continuous 21 d and were treated with 30 or 15 mg·kg^-1 of AF for 21 d. Control rats were maintained in completely non stressed conditions. Behavioral tests and biochemical analysis were applied to investigating a regulatory mechanism of anti-stress of AF. Treatment with AF significantly restored the depressant-like behaviors. Besides, AF increased the levels of 5-hydroxytryptophan (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), noradrenaline (NE) and dopamine (DA) in the hippocampus and increased the level of brain-derived neurotrophic factor (BDNF) in serum and protein expression in hippocampus. In addition, AF decreased the levels of hypothalamo-pituitary-adrenal (HPA) cascade, reduced the level of NO and cGMP in serum and inhibited the overexpression of 5-HT_2AR mRNA and protein expression. Taken together, AF can modulate the NO-mediated network pathway in the hippocampus against stress-induced depressive-like behaviors. These physiological and behavioral changes allow rats to avoid potential deleterious effects of stress that may result from chronically elevated levels of glucocorticosteroids over days.

Medicinal Plants in the Treatment of Depression: Evidence from Preclinical Studies

Medicinal plants and their extracts are natural remedies with enormous potential for treating various diseases, including depression and anxiety. In the case of depression, hundreds of plants have traditionally been used in folk medicine for generations. Different plant extracts and natural products have been analyzed as potential antidepressant agents with validated models to test for antidepressant-like effects in animals, although other complementary studies have also been employed. Most of these studies focus on the possible mediators implicated in these potential effects, with dopamine, serotonin, and noradrenaline being the principal neurotransmitters implicated, both through interference with receptors and with their metabolism by monoamino oxidases, as well as through neuro-endocrine and neuroprotective effects. There are approximately 650 reports of antidepressant-like medicinal plants in PubMed; 155 of them have been compiled in this review, with a relevant group yielding positive results. Saffron and turmeric are the most relevant species studied in both preclinical and clinical studies; St. John's wort or kava have also been tested extensively. To the best of our knowledge, no review to date has provided a comprehensive understanding of the biomolecular mechanisms of action of these herbs or of whether their potential effects could have real benefits. The purpose of this narrative review is to provide an update regarding medicinal plants from the year 2000 to the present to examine the therapeutic potential of these antidepressant-like plants in order to contribute to the development of new therapeutic methods to alleviate the tremendous burden that depression causes worldwide.

Genus Paeonia: A comprehensive review on traditional uses, phytochemistry, pharmacological activities, clinical application, and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Paeonia, which comprises approximately 52 shrubs or herbaceous perennials around the world, is the only genus of the Paeoniaceae and is pervasively distributed in Asia, southern Europe, and North America. Many species of the genus Paeonia have been used for centuries in ethnomedical medical systems.

AIM OF THE REVIEW

The present study aims to summarize the traditional uses, clinical applications, and toxicology of the genus Paeonia, to critically evaluate the state-of-the-art phytochemical and pharmacological studies of this genus published between 2011 and 2020, and to suggest directions for further in-depth research on Paeonia medicinal resources.

MATERIALS AND METHODS

Popular and widely used databases such as PubMed, Scopus, Science Direct, and Google Scholar were searched using the various search strings; from these searches, a number of citations related to the traditional uses, phytochemistry, biological activities, clinical application, and toxicology of the genus Paeonia were retrieved.

RESULTS

The use of 21 species, 2 subspecies, and 7 varieties of the genus Paeonia as traditional herbal remedies has been reported, and many ethnomedicinal uses, such as the treatment of hematemesis, blood stasis, dysmenorrhea, amenorrhea, epilepsy, spasms, and gastritis, have been recorded. The roots and root bark are the most frequently reported parts of the plants used in medicinal applications. In phytochemical investigations, 451 compounds have been isolated from Paeonia plants to date, which contains monoterpenoid glucosides, flavonoids, tannins, stilbenes, triterpenoids and steroids, and phenols. Studies of their pharmacological activities have revealed the antioxidant, anti-inflammatory, antitumour, antibacterial, antiviral, cardiovascular protective, and neuroprotective properties of the genus Paeonia. In particular, some bioactive extracts and compounds (total glucosides of peony (TGP), paeonol, and paeoniflorin) have been used as therapeutic drugs or tested in clinical trials. In addition to the "incompatibility" of the combined use of "shaoyao" and Veratrum nigrum L. roots in traditional Chinese medicine theory, Paeonia was considered to have no obvious toxicity based on the available toxicological tests.

CONCLUSION

A large number of phytochemical and pharmacological reports have indicated that Paeonia is an important medicinal herb resource, and some of its traditional uses including the treatment of inflammation and cardiovascular diseases and its use as a neuroprotective agent, have been partially confirmed through modern pharmacological studies. Monoterpenoid glucosides are the main active constituents. Although many compounds have been isolated from Paeonia plants, the biological activities of only a few of these compounds (paeoniflorin, paeonol, and TGP) have been extensively investigated. Some paeoniflorin structural analogues and resveratrol oligomers have been preliminarily studied. With the exception of several species (P. suffruticosa, P. ostii, P. lactiflora, and P. emodi) that are commonly used in folk medicine, many medicinal species within the genus do not receive adequate attention. Conducting phytochemical and pharmacological experiments on these species can provide new clues that may lead to the discovery of medicinal resources. It is necessary to identify the effective phytoconstituents of crude extracts of Paeonia that displayed pharmacological activities by bioactivity-guided isolation. In addition, comprehensive plant quality control, and toxicology and pharmacokinetic studies are needed in the future studies.

Effect of chronic unpredictable mild stress on the expression profile of serotonin receptors in rats and mice: a meta-analysis

Chronic-stress-induced depression is recognized as a widespread public health concern. Selective serotonin reuptake inhibitors (SSRIs) have been the most common treatment for this illness. However, the role of 5-hydroxytryptamine (5-HT) receptor subtypes in stress-induced depression remains unclear. Evidence from Animal studies has reported a variety of results regarding the effects of chronic unpredictable mild stress (CUMS) on serotonin signaling pathways and 5-HT receptor subtypes. This divergence may rely on differences in protocols, methods, and studied pathways. Thus, the aim of this systematic review was to weigh the currently available findings regarding serotonin receptor changes in animal models of CUMS. Overall, our meta-analysis results showed the association of altered expression of 5-HT_1A receptors in the frontal cortex and 5-HT_2A receptors both in the whole cortex and the hypothalamus of rats following CUMS. Moreover, by using a qualitative-structured analysis and the application of risk-of-bias tools, we identified possible sources of data variation between the studied literature, which should be taken into account in future animal studies of chronic-stress induced depression.

Albiflorin Attenuates Mood Disorders Under Neuropathic Pain State by Suppressing the Hippocampal NLRP3 Inflammasome Activation During Chronic Constriction Injury

BACKGROUND

Neuropathic pain is a multifaceted and ubiquitous disease across the globe. Mood disorders, such as anxiety and depression, are frequently observed in patients suffering from neuropathic pain. Both neuropathic pain and comorbid mood disorders seriously impact quality of life. Accumulated evidence shows that activation of the NOD-like receptor protein 3 (NLRP3) inflammasome is involved in the neuroinflammatory pathogenesis of neuropathic pain, anxiety, and depression. However, the role of the NLRP3 inflammasome in the pathological process of anxiety and depression under the neuropathic pain state has not been fully described. Albiflorin, a monoterpene glycoside, may be a potential regulator of the NLRP3 inflammasome, but it is not clear whether albiflorin relates to NLRP3 inflammasome activation.

METHODS

We used a systematic pharmacological method to confirm whether the activation of the NLRP3 inflammasome in the hippocampus was involved in the development of neuropathic pain associated with mood disorders and whether albiflorin could be an effective treatment for these symptoms.

RESULTS

The NLRP3 inflammasome contributed to the neuropathic pain and comorbid anxiety and depression-like behaviors induced by chronic constriction injury of the sciatic nerve, and albiflorin may relieve these symptoms via inhibition of the NLRP3 inflammasome activity. Moreover, albiflorin enhanced the translocation of the nuclear factor erythroid 2-related factor 2 into the nucleus and suppressed nuclear factor-kappa B activity in the hippocampus.

CONCLUSIONS

Albiflorin, as a potential therapeutic agent, might greatly improve the overall symptoms of neuropathic pain.

Total glucosides of paeony: A review of its phytochemistry, role in autoimmune diseases, and mechanisms of action

ETHNOPHARMACOLOGICAL RELEVANCE

Paeoniae Radix Alba (PRA, called baishao in China), the root of Paeonia lactiflora Pall., has shown a rich medicinal value for more than 2000 years. PRA is used in local medicine and traditional medicine for autoimmune diseases associated with inflammation. At present, total glucosides of paeony (TGP), the main active ingredient of PRA, has been developed into a preparation for the treatment of autoimmune diseases, as TGP exhibits the effect of regulating immunity, anti-inflammatory, and analgesic effects.

AIM OF THE REVIEW

TGP was developed and applied to inflammation-related autoimmune diseases in modern clinical practice. Based on its application in traditional prescriptions, this article reviews PRA's botany and phytochemistry (including its extraction process and quality control), and discusses the clinical application and pharmacological research of TGP as an anti-inflammatory drug from the perspective of ethnopharmacology. Additionally, we review modern pharmacological and molecular-target research on TGP and discuss the mechanisms of TGP in treating autoimmune diseases. Through a systematic literature review, we also highlight the clinical efficacy of TGP in the treatment of immune diseases, and provide a reference for the continued scientific development and quality control of TGP so that its wider application and clinical value can be fully realized.

MATERIALS AND METHODS

Literature search was conducted through the Web of Science, Baidu Scholar, ScienceDirect, PubMed, CNKI, and WanFang DATA using the keywords "Total glucosides of paeony", "Paeonia lactiflora Pall. ", "Paeonia veitchii Lynch", "Paeoniae Radix Alba or white peony", "Paeoniae Radix Rubra or red peony", "Paeoniflorin", "Albiflorin", "Autoimmune diseases", and their combinations. In addition, information was collected from relevant textbooks, reviews, and documents.

RESULTS

Approximately 15 compounds have been identified in TGP, of which paeoniflorin and albiflorin are the most common constituents. In recent years, studies have found that TGP and its main chemical components are effective in the treatment of autoimmune diseases, such as rheumatoid arthritis, psoriasis, oral lichen planus, and Sjogren's syndrome. TGP has a variety of pharmacological effects related to PRA traditional effects, including anti-organ-damage, anti-inflammatory, analgesic, antioxidant, cardiovascular, and nervous-system protection. Previously published reports on TGP treatment of autoimmune diseases have shown that TGP regulates intracellular pathways, such as the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), mitogen-activated protein kinase (MAPK), and phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathways. However, there is no standardized preparation method for TGP, and there is insufficient quality control of formulations. Many related pharmacological studies have not tested TGP components, and the validity of such pharmacological results requires further verification.

CONCLUSIONS

Modern pharmacological research on TGP is based on the traditional usage of PRA, and its folk medicinal value in the treatment of autoimmune diseases has now been verified. In particular, TGP has been developed into a formulation used clinically for the treatment of autoimmune diseases. The combination of TGP capsules and chemicals to treat autoimmune diseases has the effect of increasing efficacy and reducing toxicity. Based on further research on its preparation, quality control, and mechanisms of action, TGP is expected to eventually play a greater role in the treatment of autoimmune diseases.

Involvement of mTOR-related signaling in antidepressant effects of Sophoraflavanone G on chronically stressed mice

SophoraflavanoneG (SG), an important prenylated flavonoid isolated from Sophoraalopecuroides.L, is effective for many illnesses. The present study was designed to investigate whether the compound could reverse depressive-like symptoms and investigate its possible mechanisms. Chronic Unpredictable Mild Stress (CUMS) mice were treated with fluoxetine and SG. The immobility time in forced swimming test (FST) and tail suspension test (TST) were recorded. The levels of pro-inflammatory cytokines and neurotransmitters in the hippocampus were evaluated. Furthermore, the protein expressions of PI3K, AKT, mTOR, p70S6K, BDNF, and Trkb in hippocampus were detected. Rapamycin, the selective mTOR inhibitor, was used to estimate the potential mechanism. As a result, after 7 days of SG treatment, the immobility time in FST and TST was declined obviously. The levels of IL-6, IL-1β, and TNF-α in the hippocampus were significantly reduced, and the quantity of 5-HT and NE was raised considerably in SG-treated group compared with the CUMS-exposed group. Additionally, SG could up-regulate the expressions of PI3K, AKT, mTOR, 70S6K, BDNF, and Trkb. The blockade of mammalian target of rapamycin signaling blunted the antidepressant effect and reversed the up-regulation of BDNF expression caused by SG. These findings suggested that SG treatment alleviated depressive-like symptoms via mTOR-mediated BDNF/Trkb signaling.

Calotropis procera attenuates chronic unpredictable mild stress-induced depression in experimental animals

Calotropis procera (CP; Apocynaceae) is reported to have several neuroprotective activities however it's anti-depressant activity yet to be established. Therefore, the present study was proposed to evaluate the anti-depressant activity of the standardized ethanolic extract of CP (ECP) in chronic unpredictable mild stress (CUMS) paradigm exposed male rats. Animals were exposed to CUMS from day-1 (D-1) to D-28 except control group animals of the experimental schedule. ECP (50, 100 and 200 mg/kg, p.o.) and Imipramin (15.0 mg/kg, p.o.) were administered for seven consecutive days after CUMS paradigm. On D-35, ECP (200 mg/kg) significantly attenuated immobility period of the animals in both forced-swim and tail suspension and improved behavioural parameters in open-field and anhedonia in sucrose feeding tests. ECP (200 mg/kg) attenuated CUMS-induced hyperactivity of HPA-axis function. Further, ECP (200 mg/kg) mitigated CUMS-induced decrease in serotonin (5-HT), increase in 5-hydroxy indole acetic acid (5-HIAA) and increase in the ratio of 5-HIAA/5-HT in hippocampus and pre-frontal cortex. The CUMS-induced decrease in the level of expression of BDNF was significantly reversed with ECP (200 mg/kg) treatment. Moreover, ECP (200 mg/kg) significantly reduced the CUMS-induced decrease in the mitochondrial function and integrity in terms of level of formazan formed and intensity of tetramethyl rhodamine methylester dye in both the brain regions respectively. Therefore, ECP (200 mg/kg) mitigates CUMS-induced alterations in the behaviours, HPA-axis function, serotonergic activity, neurogenesis and mitochondrial function in the rodents. Thus, it can be assumed that ECP could be a potential alternative candidate in the management of depression.

Modeling Psychiatric Diseases with Induced Pluripotent Stem Cells

Neuropsychiatric disorders are a heterogeneous group of disorders that are challenging to model and treat, due to their underlying complex genetic architecture and clinical variability. Presently, increasingly more studies are making use of induced pluripotent stem cell (iPSC)-derived neurons, reprogrammed from patient somatic cells, to model neuropsychiatric disorders. iPSC-derived neurons offer the possibility to recapitulate relevant disease biology in the context of the individual patient genetic background. In addition to disease modeling, iPSC-derived neurons offer unprecedented opportunities in drug screening. In this chapter, the current status of iPSC disease modeling for neuropsychiatric disorders is presented. Both 2D and 3D disease modeling approaches are discussed as well as the generation of different neuronal cell types that are relevant for studying neuropsychiatric disorders. Moreover, the advantages and limitations are highlighted in addition to the future perspectives of using iPSC-derived neurons in the uncovering of robust cellular phenotypes that consecutively have the potential to lead to clinical developments.

Gut-brain axis metabolic pathway regulates antidepressant efficacy of albiflorin

The gut microbiota is increasingly recognized to influence brain function through the gut-brain axis. Albiflorin, an antidepressant natural drug in China with a good safety profile, is difficult to absorb and cannot be detected in the brain after oral administration. Accordingly, the antidepressant mechanism of albiflorin in vivo has not been elucidated clearly.

Methods: We identified benzoic acid as the characteristic metabolite of albiflorin in vivo and in vitro, then discovered the roles of gut microbiota in the conversion of albiflorin by carboxylesterase. Pharmacodynamic and pharmacokinetic studies were performed for the antidepressant activities of albiflorin in animals, and the efficacy of benzoic acid in inhibiting D-amino acid oxidase (DAAO) in brain was further investigated.

Results: We validated that gut microbiota transformed albiflorin to benzoic acid, a key metabolite in the intestine that could cross the blood-brain barrier and, as an inhibitor of DAAO in the brain, improved brain function and exerted antidepressant activity in vivo. Intestinal carboxylesterase was the crucial enzyme that generated benzoic acid from albiflorin. Additionally, the regulatory effect of albiflorin on the gut microbiota composition was beneficial to alleviate depression.

Conclusion: Our findings suggest a novel gut-brain dialogue through intestinal benzoic acid for the treatment of depression and reveal that the gut microbiota may play a causal role in the pathogenesis and treatment of the central nervous system disease.

Platelet serotonin and serotonin transporter as peripheral surrogates in depression and anxiety patients

Previous studies suggested that serotonergic neurons and platelets share similarities in serotonin (5-HT) uptake by serotonin transporter (SERT), storage, metabolism and release mechanisms, indicating that platelets may be used as a reliable peripheral surrogate to measure central SERT activity in neuropsychiatric research. In this study, platelet 5-HT content and 5-HT uptake capacity of SERT in depression and anxiety patients were measured by ELISA and flow cytometry with IDT307 at baseline and after serotonin reuptake inhibitors (SSRIs) treatment for 4 weeks. Healthy persons matched with age and gender were used as reference. The clinical presentations of the patients were assessed with Hamilton Depression (HAMD) and Anxiety Rating Scales (HAMA) at the same time points. Compared to healthy subjects, anxiety and depression patients showed higher levels of platelet 5-HT and IDT307 fluorescence intensity, but the values were comparable between the patient groups. SSRIs administration for 4 weeks significantly decreased scores of HAMD (29 vs 14) and HAMA (22 vs 14) in depression and anxiety patients, respectively; while it decreased platelet 5-HT content, but did not change the IDT307 fluorescence intensity of platelets. After incubation with fluoxetine in vitro, the IDT307 fluorescence intensity of isolated platelets from both healthy subjects and patients decreased in a dose-dependent manner. These results provide further evidence supporting the employment of platelet 5-HT content and SERT as peripheral surrogates in depression and anxiety patients, and are of help in understanding the several weeks' delay from the initiation of antidepressant medication to their full therapeutic effects in the patients.

Modeling consequences of prolonged strong unpredictable stress in zebrafish: Complex effects on behavior and physiology

Chronic stress is the major pathogenetic factor of human anxiety and depression. Zebrafish (Danio rerio) have become a novel popular model species for neuroscience research and CNS drug discovery. The utility of zebrafish for mimicking human affective disorders is also rapidly growing. Here, we present a new zebrafish model of clinically relevant, prolonged unpredictable strong chronic stress (PUCS). The 5-week PUCS induced overt anxiety-like and motor retardation-like behaviors in adult zebrafish, also elevating whole-body cortisol and proinflammatory cytokines - interleukins IL-1β and IL-6. PUCS also elevated whole-body levels of the anti-inflammatory cytokine IL-10 and increased the density of dendritic spines in zebrafish telencephalic neurons. Chronic treatment of fish with an antidepressant fluoxetine (0.1mg/L for 8days) normalized their behavioral and endocrine phenotypes, as well as corrected stress-elevated IL-1β and IL-6 levels, similar to clinical and rodent data. The CNS expression of the bdnf gene, the two genes of its receptors (trkB, p75), and the gfap gene of glia biomarker, the glial fibrillary acidic protein, was unaltered in all three groups. However, PUCS elevated whole-body BDNF levels and the telencephalic dendritic spine density (which were corrected by fluoxetine), thereby somewhat differing from the effects of chronic stress in rodents. Together, these findings support zebrafish as a useful in-vivo model of chronic stress, also calling for further cross-species studies of both shared/overlapping and distinct neurobiological responses to chronic stress.

Advances in the Preclinical Study of Some Flavonoids as Potential Antidepressant Agents

Flavonoids are phenolic compounds found commonly in plants that protect them against the negative effects of environmental insults. These secondary metabolites have been widely studied in preclinical research because of their biological effects, particularly as antioxidant agents. Diverse flavonoids have been studied to explore their potential therapeutic effects in the treatment of disorders of the central nervous system, including anxiety and depression. The present review discusses advances in the study of some flavonoids as potential antidepressant agents. We describe their behavioral, physiological, and neurochemical effects and the apparent mechanism of action of their preclinical antidepressant-like effects. Natural flavonoids produce antidepressant-like effects in validated behavioral models of depression. The mechanism of action of these effects includes the activation of serotonergic, dopaminergic, noradrenergic, and γ-aminobutyric acid-ergic neurotransmitter systems and an increase in the production of neural factors, including brain-derived neurotrophic factor and nerve growth factor. Additionally, alterations in the function of tropomyosin receptor kinase B and activity of the enzyme monoamine oxidase A have been reported. In conclusion, preclinical research supports the potential antidepressant effects of some natural flavonoids, which opens new possibilities of evaluating these substances to develop complementary therapeutic alternatives that could ameliorate symptoms of depressive disorders in humans.

Mechanisms of P-Glycoprotein Modulation by Semen Strychni Combined with Radix Paeoniae Alba

Semen Strychni has been extensively used as a Chinese herb, but its therapeutic window is narrowed by the strong toxicity of the compound, which limits its effectiveness. Radix Paeoniae Alba has been reported to reduce the toxic effects and increase the therapeutic effects of Semen Strychni, but the underlying mechanism remains unknown. This research aimed to explore the mechanism through which P-glycoprotein (P-gp) is modulated by Semen Strychni combined with Radix Paeoniae Alba in vitro. An MTT assay was used to study cytotoxicity in an MDCK-MDR1 cell model. Rh123 efflux and accumulation were measured to assess P-gp function. The expression levels of MDR1 mRNA and P-gp protein in MDCK-MDR1 cells were investigated. A P-gp ATPase activity assay kit was applied to detect the effect on P-gp ATPase activity. Semen Strychni combined with Radix Paeoniae Alba could induce P-gp-mediated drug transport by inhibiting brucine and strychnine transport in MDCK-MDR1 cells, enhancing the P-gp efflux function, upregulating the P-gp expression and MDR1 mRNA levels, and stimulating P-gp ATPase activity.

Identification of NF-κB as Determinant of Posttraumatic Stress Disorder and Its Inhibition by the Chinese Herbal Remedy Free and Easy Wanderer

Posttraumatic stress disorder (PTSD) is a mental disorder developing after exposure to traumatic events. Although psychotherapy reveals some therapeutic effectiveness, clinically sustainable cure is still uncertain. Some Chinese herbal formulae are reported to work well clinically against mental diseases in Asian countries, but the safety and their mode of action are still unclear. In this study, we investigated the mechanisms of Chinese remedy free and easy wanderer (FAEW) on PTSD. We used a reverse pharmacology approach combining clinical data to search for mechanisms of PTSD with subsequent in vitro verification and bioinformatics techniques as follows: (1) by analyzing microarray-based transcriptome-wide mRNA expression profiling of PTSD patients; (2) by investigating the effect of FAEW and the antidepressant control drug fluoxetine on the transcription factor NF-κB using reporter cell assays and western blotting; (3) by performing molecular docking and literature data mining based on phytochemical constituents of FAEW. The results suggest an involvement of inflammatory processes mediated through NF-κB in the progression of PTSD. FAEW was non-cytotoxic in vitro and inhibited NF-κB activity and p65 protein expression. FAEW's anti-inflammatory compounds, i.e., paeoniflorin, isoliquiritin, isoliquiritin apioside and ononin were evaluated for binding to IκK and p65-RelA in a molecular docking approach. Paeoniflorin, albiflorin, baicalin, isoliquiritin and liquiritin have been reported to relieve depression in vivo or in clinical trials, which might be the active ingredients for FAEW against PTSD.

Experimental occlusal disharmony - A promoting factor for anxiety in rats under chronic psychological stress

BACKGROUND AND PURPOSE

Clinically, patients under chronic psychological stress (PS) appear to be more susceptible to occlusal disharmony (OD) compared with those without PS. OD was proved to introduce anxiety-like stress. Therefore, the purpose of the study was to investigate whether OD would affect psychological stress-induced anxiety and its underlying mechanisms.

METHODS

Chronic PS was induced by a communication box, and OD was produced by bonding a 0.3mm-thick crown on the right maxillary first molar of male Sprague-Dawley rats. Sixty-seven rats were randomly divided into 8 groups: (A) chronic PS plus OD group (n=6); (B) chronic PS plus sham OD group (n=6); (C) chronic PS only group (n=6); (D) OD group (n=6); (E) sham OD group (n=6); (F) control group (n=6); (G) naive group (n=6); (H) foot-shock group (n=25). Open-field test (OFT) and elevated plus maze test (EPM) were conducted on the 7th, 21th, 35th day to measure the anxiety level of each group except naive and foot-shock group. In addition, corticosterone (CORT) level in serum, 5-hydroxytryptamine (5-HT) and 5-HT_2A receptor (5-HT_2AR) expressions in prefrontal cortex (PFC), hippocampal CA1 and dentate gyrus (DG) areas were measured on the 35th day to elucidate the mechanism(s) by which the exacerbation occurred.

RESULTS

The significant differences in OFT and EPM tests on day 21 or day 35 between groups (p<0.01) indicated the successful establishment of animal model of PS or OD. And there was a significant increase in CORT concentration in serum (p<0.01), 5-HT expressions in PFC, hippocampal DG areas and 5-HT_2AR expressions in PFC, hippocampal CA1 areas (p<0.05) in group A, B, C, D compared with group F. Similar results were also found in group A, B, C, D when compared with group G (p<0.05) except 5-HT expression in DG area in group C and D (p>0.05), together with a gradual decrease in values of all the parameters mentioned above from group A to group G.

CONCLUSION

The significant changes in exploratory behaviors, serum CORT concentration, 5-HT and 5-HT_2AR expressions induced by OD in rats with or without chronic PS, and more obvious alterations in rats with chronic PS, may indicate that OD may be a promoting factor for anxiety through both peripheral and central pathways via the hypothalamus-pituitary-adrenal (HPA) axis and 5-HT system.

Investigation of the protective effect of Paeonia lactiflora on Semen Strychni-induced neurotoxicity based on monitoring nine potential neurotoxicity biomarkers in rat serum and brain tissue

Semen Strychni has been widely used as a traditional Chinese herb medicine, but its clinical use was limited for its potential neurotoxicity and nephrotoxicity. This study aimed to investigate S. Strychni-induced neurotoxicity and the neuro-protective effect of Paeonia lactiflora based on monitoring nine potential neurotoxicity biomarkers in rat serum and brain tissue. A sensitive liquid chromatography-tandem mass spectrometry method was developed and validated to monitor serotonin, tryptophan, dopamine, tyrosine and glutamate in serum and five brain regions (prefrontal cortex, hippocampus, striatum, cerebellum and hypothalamus). Analytes were separated on a CAPCELL CORE PC column (150 mm × 2 mm, 2.7 μm) with a gradient program of acetonitrile-water (0.2 % formic acid) and a total runtime of 7.5 min. In addition, enzyme-linked immunosorbent assay was conducted to determine four kinds of protein (tryptophan hydroxylase, tyrosine hydroxylase, endogenous brain-derived neurotrophic factor and nerve growth factor). Results demonstrated that the administration of S. Strychni could cause certain endogenous substances disorder. These analytes were found significantly changed (p < 0.05) in serum (except glutamate) and in certain tested brain regions in S. Strychni extract group. Pretreatment of P. lactiflora could significantly reverse the S. Strychni-induced neurotoxicity and normalize the levels of such endogenous substances. The study could be further used in predicting and monitoring neurotoxicity caused by other reasons, and it was expected to be useful for improving clinical use of S. Strychni through pretreatment with P. lactiflora.

A systems pharmacology approach to decipher the mechanism of danggui-shaoyao-san decoction for the treatment of neurodegenerative diseases

ETHNOPHARMACOLOGICAL RELEVANCE

Neurodegenerative diseases (NDs) is a time-dependent course for a sequence of conditions that primarily impact the neurons in the human brain, ultimately, resulting in persistence and progressive degeneration and / or death of nerve cells and reduction of cognition and memory function. Currently, there are no therapeutic approaches to cure neurodegeneration, except certain medicines that temporarily alleviate symptoms, facilitating the improvement of a patients' quality of life. Danggui-shaoyao-san (DSS), as a famous Chinese herbal formula, has been widely used in the treatment of various illnesses, including neurodegenerative diseases. Although well-practiced in clinical medicine, the mechanisms involved in DSS for the treatment of neurodegenerative diseases remain elusive.

MATERIALS AND METHODS

In the present study, a novel systems pharmacology approach was developed to decipher the potential mechanism between DSS and neurodegenerative disorders, implicated in oral bioavailability screening, drug-likeness assessment, target identification and network analysis.

RESULTS

Based on a comprehensive systems approach, active compounds of DSS, relevant potential targets and targets associated with diseases were predicted. Active compounds, targets and diseases were used to construct biological networks, such as, compound-target interactions and target-disease networks, to decipher the mechanisms of DSS to address NDs.

CONCLUSIONS

Overall, a well-understood picture of DSS, hallmarked by multiple herbs-compounds-targets-pathway-cooperation networks for the treatment of NDs, was revealed. Notably, this systems pharmacology approach provided a novel in silico approach for the development paradigm of traditional Chinese medicine (TCM) and the generation of new strategies for the management of NDs.