Anxiolytic effects of Julibroside C1 isolated from Albizzia julibrissin in mice

GABAergic implications in anxiety and related disorders

Evidence indicates that anxiety disorders arise from an imbalance in the functioning of brain circuits that govern the modulation of emotional responses to possibly threatening stimuli. The circuits under consideration in this context include the amygdala's bottom-up activity, which signifies the existence of stimuli that may be seen as dangerous. Moreover, these circuits encompass top-down regulatory processes that originate in the prefrontal cortex, facilitating the communication of the emotional significance associated with the inputs. Diverse databases (e.g., Pubmed, ScienceDirect, Web of Science, Google Scholar) were searched for literature using a combination of different terms e.g., "anxiety", "stress", "neuroanatomy", and "neural circuits", etc. A decrease in GABAergic activity is present in both anxiety disorders and severe depression. Research on cerebral functional imaging in depressive individuals has shown reduced levels of GABA within the cortical regions. Additionally, animal studies demonstrated that a reduction in the expression of GABAA/B receptors results in a behavioral pattern resembling anxiety. The amygdala consists of inhibitory networks composed of GABAergic interneurons, responsible for modulating anxiety responses in both normal and pathological conditions. The GABAA receptor has allosteric sites (e.g., α/γ, γ/β, and α/β) which enable regulation of neuronal inhibition in the amygdala. These sites serve as molecular targets for anxiolytic medications such as benzodiazepine and barbiturates. Alterations in the levels of naturally occurring regulators of these allosteric sites, along with alterations to the composition of the GABAA receptor subunits, could potentially act as mechanisms via which the extent of neuronal inhibition is diminished in pathological anxiety disorders.

Adinazolam, a Benzodiazepine-Type New Psychoactive Substance, Has Abuse Potential and Induces Withdrawal Symptoms in Rodents

Adinazolam (ADZ) is a benzodiazepine-type new psychoactive substance (NPS) with anxiolytic, anticonvulsant, and antidepressant effects. High ADZ doses have been reported to impair psychomotor performance and memory; however, the abuse potential and drug dependence of ADZ have not yet been fully investigated. In this study, we evaluated whether ADZ has abuse potential and leads to drug dependence and withdrawal symptoms. The intravenous self-administration (IVSA) test revealed that ADZ (0.01, 0.03, and 0.1 mg/kg/infusion) was self-administered significantly above vehicle levels, suggesting the reinforcing effect of ADZ. Furthermore, we revealed that treatment discontinuation following chronic ADZ administration (3 and 6 mg/kg) caused several somatic withdrawal symptoms in mice, including body tremor. Moreover, it induced motivational withdrawal signs, such as anxiety-related behavior in the elevated plus maze (EPM) test and memory deficits in the Y-maze test. After the IVSA test, an enzyme-linked immunosorbent assay (ELISA) showed that ADZ administration significantly increased the dopamine contents in the thalamus, nucleus accumbens (NAc), and ventral tegmental area (VTA). This finding was also supported by the results of the Western blot. Taken together, our results suggest that ADZ has abuse potential and can lead to drug dependence and withdrawal syndrome.

Molecular basis and mechanism of action of Albizia julibrissin in depression treatment and clinical application of its formulae

Albizzia julibrissin is empirically used as an antidepressant in clinical practice. Preclinical studies have indicated that its total extracts or bioactive constituents exerted antidepressant-like responses in animal models, providing the molecular basis to reveal its underlying mechanism of action. While attempts have been made to understand the antidepressant effect of A. julibrissin, many fundamental questions regarding its mechanism of action remain to be addressed at the molecular and systems levels. In this review, we conclusively discussed the mechanism of action of A. julibrissin and A. julibrissin formulae by reviewing recent preclinical and clinical studies conducted by using depressive animal models and depressive patients. Several representative bioactive constituents and formulae were highlighted as examples, and their mechanisms of action were discussed. In addition, some representative A. julibrissin formulae that have been shown to be compatible with conventional antidepressants in clinical practice were also reviewed. Furthermore, we discussed the future research directions to reveal the underlying mechanism of A. julibrissin at the molecular and systems levels in depression treatment. The integrated study using both the molecular and systematic approaches is required not only for improving our understanding of its molecular basis and mechanisms of action, but also for providing a way to discover novel agents or approaches for the effective and systematic treatment of depression.

A comparison review of Hehuan flowers and Hehuan bark on the traditional applications, phytochemistry and pharmacological effects

ETHNOPHARMACOLOGICAL RELEVANCE

Albizia julibrissin Durazz is a well-known medicinal plant with the Chinese name Hehuan []. Hehuan bark and Hehuan flowers have long been recognized as traditional Chinese herbal medicine for treating anxiety, melancholy, insomnia, bruises, pulmonary abscess, fractures, carbuncle, amnesia, acute conjunctivitis, blurred vision, neonatal tetanus and stroke for thousands of years. They are recorded in Chinese Pharmacopoeia separately with different properties. Until now, new chemical constituents and pharmacological activities of Hehuan have been continuously studied and revealed.

THE AIM OF THE REVIEW

This review aims to provide a comprehensive summary of traditional applications, phytochemistry, pharmacology effects, and toxicology of Hehuan bark and Hehuan flowers, and give critical assessment and point out the promising direction for further research on Hehuan.

MATERIAL AND METHODS

A literature search was undertaken on Hehuan bark and Hehuan flowers by analyzing the information from scientific databases (SciFinder, Pubmed, Elsevier, Google Scholar, Web of Science, and Baidu Scholar). We also gathered the information of Hehuan from classic herbal literatures and conference papers on ethnopharmacology.

RESULTS

According to Chinese and English documents, the medicinal history of Hehuan in China can be traced back to ad 25. Meanwhile, its medicinal history as a kind of herbal medicine can also be found in other Asian countries. So far about 140 compounds have been isolated from Hehuan bark and Hehuan flowers, including triterpenoids, flavonoids, lignans, phenolic acids, alkaloids, etc. Among them, flavonoids mainly exist in Hehuan flowers, while Hehuan bark contains lignans and saponins. The composition differences between the barks and flowers of Hehuan account for the different effects and applications. Modern pharmacological studies have indicated that crude extracts and pure compounds of Hehuan flowers and Hehuan bark have multiple pharmacological activities, such as antineoplastic, immunomodulatory, anti-inflammatory, anxiolytic, antidepressant, metabolic regulation, anti-insomnia, neuroprotective, hepatoprotective, sedative, and anti-osteolytic activities.

CONCLUSIONS

Hehuan (Albizia julibrissin Durazz) is traditionally used to relieve depression, calm nerves, promote blood circulation and reduce swelling. Modern pharmacological studies have revealed that natural products from Hehuan bark and Hehuan flowers possess extensive pharmacological activities in treating cancer, enhancing immunity, regulating metabolism, improving mental state, etc. These properties make it great clinical application potential. Further research on natural pharmaceutical chemistry, pharmacology, toxicology, pharmacokinetics, and quality standards of Hehuan are still required to verify the efficacy and safety for future clinical applications.

Molecular docking and biochemical validation of (-)-syringaresinol-4-O-β-D-apiofuranosyl-(1→2)-β-D-glucopyranoside binding to an allosteric site in monoamine transporters

Albizia julibrissin Durazz is one of the most common herbs used for depression and anxiety treatment, but its mechanism of action as an antidepressant or anxiolytic drug have not been fully understood. We previously isolated and identified one lignan glycoside compound from Albizia Julibrissin Durazz, (-)-syringaresinol-4-O-β-D-apiofuranosyl-(1→2)-β-D-glucopyranoside (SAG), that inhibited all three monoamine transporters with a mechanism of action different from that of the conventional antidepressants. In this study, we generated homology models for human dopamine transporter and human norepinephrine transporter, based on the X-ray structure of Drosophila dopamine transporter, and conducted the molecular docking of SAG to all three human monoamine transporters. Our computational results indicated that SAG binds to an allosteric site (S2) that has been demonstrated to be formed by an aromatic pocket positioned in the scaffold domain in the extracellular vestibule connected to the central site (S1) in these monoamine transporters. In addition, we demonstrated that SAG stabilizes a conformation of serotonin transporter with both the extracellular and cytoplasmic pathways closed. Furthermore, we performed mutagenesis of the residues in both the allosteric and orthosteric sites to biochemically validate SAG binding in all three monoamine transporters. Our results are consistent with the molecular docking calculation and support the association of SAG with the allosteric site. We expect that this herbal molecule could become a lead compound for the development of new therapeutic agents with a novel mechanism of action.

Rhaponticum uniflorum and Serratula centauroides Extracts Attenuate Emotional Injury in Acute and Chronic Emotional Stress

In modern life, the use of plant stress-protectors has taken on particular significance due to the wide distribution of neurosis-like and neurotic diseases caused by neuroendocrine-immune system imbalance. Special attention has been paid to the plants containing ecdysteroids, i.e., hormone-like bioactive substances with high adaptogenic activity. The article deals with the study of bioactivity of two plant extracts as Rhaponticum uniflorum (L.) DC. and Serratula centauroides L. with a high content of ecdysteroids and phenolic compounds. The models of acute and chronic emotional stress in white rats were used to estimate the stress-protective activity of R. uniflorum and S. centauroides extracts. Both extracts showed the stress-protective effect via inhibiting the development of signs induced by single and long-term effects of stress factors. In acute stress, the development of Selye's triad signs was less pronounced against the background of the plant remedies introduction. In chronic stress, the extracts prevented the development of anxiety-depressive syndrome. Besides, R. uniflorum and S. centauroides extracts banned the development of stress-induced injuries in the brain cortex and had a neuroprotective effect on ischemia against chronic stress. The stress-protective effects of both plant extracts were based on a decrease of hyperactivation of the central stress-promoting systems (sympathoadrenal, hypothalamic-pituitary-adrenal) due to their GABA-mimetic effects. Peripheral mechanisms were connected with the inhibition of free radical oxidation processes and with an increase in the endogenous antioxidant system activity. Thus, R. uniflorum and S. centauroides extracts have a high potential to increase non-specific body resistance against acute and chronic emotional stress effects.

Methoxphenidine (MXP) induced abnormalities: Addictive and schizophrenia-related behaviours based on an imbalance of neurochemicals in the brain

BACKGROUND AND PURPOSE

Methoxphenidine is a dissociative-based novel psychoactive designer drug. Although fatal accidents from methoxphenidine abuse have been reported, recreational use of the drug continues. We aim to provide scientific supportfor legal regulation of recreational abuse of methoxphenidine by demonstrating its the pharmacological action.

EXPERIMENTAL APPROACH

Addictive potential of methoxphenidine was examined using intravenous self-administration test with rats and conditioned place preference test with mice. Further, a series of behavioural tests (open field test, elevated plus maze test, novel object recognition test, social interaction test and tail suspension test) performed to assess whether methoxphenidine caused schizophrenia-related symptoms in mice. Additionally, neurotransmitter enzyme-linked immunosorbent assay and western blot were used to confirm methoxphenidine-induced neurochemical changes in specific brain regions related to abnormal behaviours.

KEY RESULTS

Methoxphenidine caused addictive behaviours via reinforcing and rewarding effects. Consistently, methoxphenidine induced over-activation of dopamine pathways in the nuclear accumbens, indicating activation of the brain reward circuit. Also, methoxphenidine caused all categories of schizophrenia-related symptoms, including positive symptoms (hyperactivity, impulsivity), negative symptoms (anxiety, social withdrawal, depression) and cognitive impairment. Consistently, methoxphenidine led to the disruption of the hippocampal-prefrontal cortex pathway that is considered to be pathological involved in schizophrenia.

CONCLUSIONS AND IMPLICATIONS

We demonastrate that methoxphenidine causes addictive and schizophrenia-like behaviours and induces neurochemical changes in brain regions associated with these behaviours. We propose that methoxphenidine could be used in developing useful animal disease models and that it also requires legal restrictions on its recreational use.

Synthesis, Molecular Docking and In Vivo Biological Evaluation of Iminostilbene Linked 1,2,3-Triazole Pharmacophores as Promising AntiAnxiety and Anti-Inflammatory Agents

BACKGROUND

Iminostilbene and 1,2,3-triazole ring containing compounds are considered as beneficial substrates in drug design.

OBJECTIVES

This study was aimed at the synthesis of novel series of iminostilbene linked 1,2,3- triazole pharmacophores (7c-n) by Cu(I) catalyzed 1,3 dipolar cycloaddition reaction between 5- (Prop-2-yn-1-yl)-5H-dibenzo[b,f]azepine (7b) and various substituted azidobenzene derivatives (3cn).

METHODS

The chemical structures of compounds were confirmed by 1 H NMR, 13C NMR, LC-MS and molecular docking studies were carried out through HEX docking software.

RESULTS

The in vivo anti anxiety capacity of the compounds was evaluated by using "elevated plus maze" (EPM), anxiety model. The results exhibited that compounds (7d, 7e, 7j and 7k) have a higher anti anxiety effect close to diazepam. The anti-inflammatory activities of the synthesized compounds were evaluated by "Carrageenan-induced rat paw edema" model, compounds (7b, 7c, 7d, 7f, and 7j) demonstrated statistically significant inflammatory activity. Molecular docking analysis revealed that compounds (7d, 7e and 7j) bound to GABA(A) proteins show more efficiency when compared to the other analogues in the series.

CONCLUSION

These results suggest that compounds (7b, 7c, 7d, 7e, 7f, and 7j) can be considered as novel candidates for anti-anxiety and anti-inflammatory agents. Moreover, docking method was used to elucidate anti-anxiety effect of compounds. This study furnished insight into the molecular interactions of synthesized compounds with their physiological targets, and the potential to develop bioactive heterocyclic compounds.

Studying CNS effects of Traditional Chinese Medicine using zebrafish models

ETHNOPHARMACOLOGICAL RELEVANCE

Although Traditional Chinese Medicine (TCM) has a millennia-long history of treating human brain disorders, its complex multi-target mechanisms of action remain poorly understood. Animal models are currently widely used to probe the effects of various TCMs on brain and behavior. The zebrafish (Danio rerio) has recently emerged as a novel vertebrate model organism for neuroscience research, and is increasingly applied for CNS drug screening and development.

AIM OF THE STUDY

As zebrafish models are only beginning to be applied to studying TCM, we aim to provide a comprehensive review of the TCM effects on brain and behavior in this fish model species.

MATERIALS AND METHODS

A comprehensive search of published literature was conducted using biomedical databases (Web of Science, Pubmed, Sciencedirect, Google Scholar and China National Knowledge Internet, CNKI), with key search words zebrafish, brain, Traditional Chinese Medicine, herbs, CNS, behavior.

RESULTS

We recognize the developing utility of zebrafish for studying TCM, as well as outline the existing model limitations, problems and challenges, as well as future directions of research in this field.

CONCLUSIONS

We demonstrate the growing value of zebrafish models for studying TCM, aiming to improve our understanding of TCM' therapeutic mechanisms and potential in treating brain disorders.

The ethnopharmacology, phytochemistry, pharmacology and toxicology of genus Albizia: A review

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Albizia (Leguminosae) comprises about 150 species and some species have been used for the treatment of rheumatism, stomachache, cough, diarrhea, and wounds in traditional and local medicine. The aim of the review: This review article documents and critically assesses the current status of the traditional uses, phytochemistry, pharmacology, and toxicology of the Albizia species.

MATERIALS AND METHODS

All provided literatures on the Albizia species were searched using the electronic databases (e.g. Web of Science, Elsevier, Springer, PubMed, ACS, CNKI, Google Scholar, and Baidu Scholar), books, and theses with keywords of 'Albizia' and 'Albizzia'.

RESULTS

Albizia species have been used for melancholia, insomnia, wounds, fever, abscesses, diabetes, headache, stomachache, diarrhea, cough, rheumatism, snake bite, malaria, and parasitic infection in traditional and local medicine. These plants mainly contain triterpenoid saponins, flavonoids, lignanoids, alkaloids, phenolic glycosides, etc. Albizia species have been demonstrated to possess various pharmacological activities. Among them, the antidiabetic, anti-inflammatory, antifertility, antianxiety, antidepressant, and anti-fever properties are consistent with the traditional and local applications of the Albizia species.

CONCLUSIONS

The traditional and local uses of Albizia species have been partially demonstrated by the pharmacological investigation. However, some traditional applications have not been assessed scientifically due to incomplete methodologies and ambiguous findings. Moreover, no clinical evidences support the health benefits of these plants. The systematic and comprehensive preclinical studies and clinical trials are still required to verify the pharmacological activities, clinical efficacy, and safety of Albizia species.

(-)-Syringaresinol-4-O-β-D-glucopyranoside from Cortex Albizziae inhibits corticosterone-induced PC12 cell apoptosis and relieves the associated dysfunction

The neuroprotective effects and potential mechanisms of (-)-Syringaresinol-4-O-β-D-glucopyranoside (SRG), a natural lignan glycoside extracted from Cortex Albizziae, were investigated using corticosterone (CORT)-induced PC12 cells as an in vitro anxiety model. PC12 cells were treated with 100 μM CORT and 5, 10, or 20 μM SRG for 48 h. Cell viability and lactate dehydrogenase (LDH) leakage were measured. Apoptosis were detected using FITC-coupled Annexin V (AV) and propidium iodide (PI) staining flow cytometric analyses and TUNEL assays. Rhodamine 123 and Fluo-3-AM staining flow cytometric analyses were used to detect mitochondrial membrane potential (ΔΨm) and intracellular calcium concentration ([Ca²⁺]_i), respectively. Western blot was used to detect brain-derived neurotrophic factor (BDNF), Bax, Bcl-2, cAMP-response element binding protein (CREB), cytosolic cytochrome c (Cyt c), caspase-3, and cleaved caspase-3. Experimental data showed that SRG promoted cell proliferation, reduced LDH release, inhibited apoptosis, improved ΔΨm values, decreased [Ca²⁺]_i, up-regulated CREB, BDNF, and Bcl-2, down-regulated Bax and Cyt c protein expression levels, and reduced caspase-3 activity. This suggests that SRG has neuroprotective and antiapoptotic effects in the pathogenesis of anxiety disorders, and its mechanisms are partly connecte to inhibition of the mitochondrial apoptotic pathway and activation of pathways involving CREB and BDNF.

Network Pharmacology-based Research of Active Components of Albiziae Flos and Mechanisms of Its Antidepressant Effect

Albiziae Flos (AF) has been experimentally proven to have an antidepressant effect. However, due to the complexity of botanical ingredients, the exact pharmacological mechanism of action of AF in depression has not been completely deciphered. This study used the network pharmacology method to construct a component-target-pathway network to explore the active components and potential mechanisms of action of AF. The methods included collection and screening of chemical components, prediction of depression-associated targets of the active components, gene enrichment, and network construction and analysis. Quercetin and 4 other active components were found to exert antidepressant effects mainly via monoaminergic neurotransmitters and cAMP signaling and neuroactive ligand-receptor interaction pathways. DRD2, HTR1A, and SLC6A4 were identified as important targets of the studied bioactive components of AF. This network pharmacology analysis provides guidance for further study of the antidepressant mechanism of AF.

Herbal medicine for psychiatric disorders: Psychopharmacology and neuroscience-based nomenclature

Objectives: Herbs are frequently and concurrently used with prescribed drugs by patients worldwide. While clinical trials have found some herbs to be as useful as standard psychiatric drugs, most clinicians are unaware of their pharmacological mechanisms.Methods: We searched English language and other language literature with English abstracts listed in PubMed website, supplemented by additional through Google Scholar's free academic paper abstract website for publications on herbs, focussing on their clinical use in mental disorders, their neurobiology and their pharmacology.Results: A major reason for herbs remaining outside of mainstream psychiatry is that the terminology and concepts in herbal medicine are not familiar to psychiatrists in general. Many publications regarding the use of herbal medicine for psychiatric disorders are deficient in details regarding diagnosis, criteria for response and the neurobiology details compared with publications on standard psychotropic drugs. Nomenclature for herbal medicine is usually confusing and is not conducive to an easy understanding of their mode of action in psychiatric disorders.Conclusions: The recent neuroscience-based nomenclature (NbN) for psychotropics methodology would be a logical application to herbal medicine in facilitating a better understanding of the use of herbal medicine in psychiatry.

Albizia julibrissin Ameliorates Memory Loss Induced by Insomnia in Drosophila

In clinical practice in Taiwan, Albizia julibrissin is the most prescribed Chinese herbal medicine for insomnia. Short-term insomnia and hypnotic use both attenuate cognitive functions, especially learning memory. In previous studies, A. julibrissin exhibits sedative activity, antidepressant-like effects, and protection of learning and memory against amnesia. However, whether A. julibrissin ameliorates memory loss caused by short-term sleep deprivation is not clear. We utilized the sleep-deprived Drosophila model and olfactory associative learning-memory assay to test the effects of A. julibrissin on sleep-deprivation induced memory loss. We found that A. julibrissin ameliorated 3-hour memory but not 1-hour memory or instant learning. The findings might be applied to an anticipated short-term sleep disturbance.

GABA and 5-HT Systems Are Involved in the Anxiolytic Effect of Gan-Mai-Da-Zao Decoction

The Gan-Mai-Da-Zao (GMDZ) decoction is one of the most famous Chinese medicine prescriptions to treat emotional diseases in China. Here we examined the anxiolytic-like effects of the GMDZ decoction in mice. The mice were orally administered with GMDZ decoction (1, 2, and 4 g/kg, respectively) for 7 days, diazepam (2 mg/kg, p.o.) and buspirone (5 mg/kg, p.o.) were used as positive controls. Then, elevated plus maze (EPM) test, light/dark box (LDB) test, and marble burying (MB) test, open field (OF) test and rota-rod test were performed. We found that GMDZ treatment (2 and 4 g/kg) significantly increased the percentage of open arm entries and time spent on the open arms in EPM as compared to the control. GMDZ treatment also significantly increased the time spent in the light box and the number of light box entries in LDB and reduced the number of marbles buried in MB. Similarly to those observed with diazepam and buspirone. In contrast, GMDZ did not affect the locomotor activity in the OF and motor coordination in the rota-rod test. Furthermore, the anxiolytic-like effects induced by GMDZ were inhibited by the γ-aminobutyric acid-A (GABA_A) receptor antagonist flumazenil and 5-hydroxytryptamine-1A (5-HT_1A) receptor antagonist WAY-100635. These results showed that GMDZ possesses anxiolytic-like effects in animal models, and its mechanism of action might be modulated by 5-HT_1A and GABA_A receptors.

Structure-Dependent Activity of Natural GABA(A) Receptor Modulators

GABA(A) receptors are ligand-gated ion channels consisting of five subunits from eight subfamilies, each assembled in four hydrophobic transmembrane domains. This pentameric structure not only allows different receptor binding sites, but also various types of ligands, such as orthosteric agonists and antagonists, positive and negative allosteric modulators, as well as second-order modulators and non-competitive channel blockers. A fact, that is also displayed by the variety of chemical structures found for both, synthetic as well as nature-derived GABA(A)-receptor modulators. This review covers the literature for natural GABA(A)-receptor modulators until the end of 2017 and discusses their structure-activity relationship.

Therapeutical strategies for anxiety and anxiety-like disorders using plant-derived natural compounds and plant extracts

Anxiety and anxiety-like disorders describe many mental disorders, yet fear is a common overwhelming symptom often leading to depression. Currently two basic strategies are discussed to treat anxiety: pharmacotherapy or psychotherapy. In the pharmacotherapeutical clinical approach, several conventional synthetic anxiolytic drugs are being used with several adverse effects. Therefore, studies to find suitable safe medicines from natural sources are being sought by researchers. The results of a plethora experimental studies demonstrated that dietary phytochemicals like alkaloids, terpenes, flavonoids, phenolic acids, lignans, cinnamates, and saponins or various plant extracts with the mixture of different phytochemicals possess anxiolytic effects in a wide range of animal models of anxiety. The involved mechanisms of anxiolytics action include interaction with γ-aminobutyric acid A receptors at benzodiazepine (BZD) and non-BZD sites with various affinity to different subunits, serotonergic 5-hydrodytryptamine receptors, noradrenergic and dopaminergic systems, glutamate receptors, and cannabinoid receptors. This review focuses on the use of both plant-derived natural compounds and plant extracts with anxiolytic effects, describing their biological effects and clinical application.

Involvement of 5-HT1A Receptors in the Anxiolytic-Like Effects of Quercitrin and Evidence of the Involvement of the Monoaminergic System

Quercitrin is a well-known flavonoid that is contained in Flos Albiziae, which has been used for the treatment of anxiety. The present study investigated the anxiolytic-like effects of quercitrin in experimental models of anxiety. Compared with the control group, repeated treatment with quercitrin (5.0 and 10.0 mg/kg/day, p.o.) for seven days significantly increased the percentage of entries into and time spent on the open arms of the elevated plus maze. In the light/dark box test, quercitrin exerted an anxiolytic-like effect at 5 and 10 mg/kg. In the marble-burying test, quercitrin (5.0 and 10.0 mg/kg) also exerted an anxiolytic-like effect. Furthermore, quercitrin did not affect spontaneous locomotor activity. The anxiolytic-like effects of quercitrin in the elevated plus maze and light/dark box test were blocked by the serotonin-1A (5-hydroxytryptamine-1A (5-HT_1A)) receptor antagonist WAY-100635 (3.0 mg/kg, i.p.) but not by the γ-aminobutyric acid-A (GABA_A) receptor antagonist flumazenil (0.5 mg/kg, i.p.). The levels of brain monoamines (5-HT and dopamine) and their metabolites (5-hydroxy-3-indoleacetic acid, 3,4-dihydroxyphenylacetic acid, and homovanillic acid) were decreased after quercitrin treatment. These data suggest that the anxiolytic-like effects of quercitrin might be mediated by 5-HT_1A receptors but not by benzodiazepine site of GABA_A receptors. The results of the neurochemical studies suggest that these effects are mediated by modulation of the levels of monoamine neurotransmitters.

Biphasic Effects of α-Asarone on Immobility in the Tail Suspension Test: Evidence for the Involvement of the Noradrenergic and Serotonergic Systems in Its Antidepressant-Like Activity

Alpha (α)-asarone is one of the main psychoactive compounds, present in Acorus species. Evidence suggests that the α-asarone possess an antidepressant-like activity in mice. However, the exact dose-dependent effect of α-asarone and mechanism(s) involved in the antidepressant-like activity are not clear. The present study aimed to investigate the dose-dependent effect of α-asarone and the underlining mechanism(s) involved in the antidepressant-like activity of α-asarone in the mouse model of tail suspension test (TST). In this study, the acute effect of α-asarone per se at different doses (10–100 mg/kg, i.p.) on immobility in the TST was studied. Additionally, the possible mechanism(s) involved in the antidepressant-like effect of α-asarone was studied using its interaction with noradrenergic and serotonergic neuromodulators in the TST. The present results reveal that the acute treatment of α-asarone elicited biphasic responses on immobility such that the duration of the immobility time is significantly reduced at lower doses (15 and 20 mg/kg, i.p.) but increased at higher doses (50 and 100 mg/kg, i.p.) in the TST. Besides, α-asarone at higher doses (50 and 100 mg/kg, i.p.) significantly decreased the spontaneous locomotor activity. Moreover, pretreatment of mice with noradrenergic neuromodulators such as AMPT (100 mg/kg, i.p., a catecholamine synthesis inhibitor), prazosin (1 mg/kg, i.p., an α₁-adrenoceptor antagonist), yohimbine (1 mg/kg, i.p., an α₂-adrenoceptor antagonist) and with serotonergic neuromodulators such as PCPA (100 mg/kg, i.p., once daily for four consecutive days, a serotonin synthesis inhibitor,) and WAY100635 (0.1 mg/kg, s.c., a selective 5-HT_1A receptor antagonist) significantly reversed the anti-immobility effect of α-asarone (20 mg/kg, i.p.). Taken together, our results suggest that the acute treatment with α-asarone elicited biphasic actions in the TST in which antidepressant-like effect was seen at relatively lower doses (15 and 20 mg/kg, i.p.) and depressive-like activity at relatively higher doses (50 and 100 mg/kg, i.p.). Furthermore, it has been revealed that the antidepressant-like effect of α-asarone could be mediated through both noradrenergic (α₁ and α₂ adrenoceptors) and serotonergic (particularly, 5-HT_1A receptors) systems.

Lotus Leaf Alkaloid Extract Displays Sedative-Hypnotic and Anxiolytic Effects through GABAA Receptor

Lotus leaves have been used traditionally as both food and herbal medicine in Asia. Open-field, sodium pentobarbital-induced sleeping and light/dark box tests were used to evaluate sedative-hypnotic and anxiolytic effects of the total alkaloids (TA) extracted from the herb, and the neurotransmitter levels in the brain were determined by ultrafast liquid chromatography-tandem mass spectrometry. The effects of picrotoxin, flumazenil, and bicuculline on the hypnotic activity of TA, as well as the influence of TA on Cl(-) influx in cerebellar granule cells, were also investigated. TA showed a sedative-hypnotic effect by increasing the brain level of γ-aminobutyric acid (GABA), and the hypnotic effect could be blocked by picrotoxin and bicuculline, but could not be antagonized by flumazenil. Additionally, TA could increase Cl(-) influx in cerebellar granule cells. TA at 20 mg/kg induced anxiolytic-like effects and significantly increased the concentrations of serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), and dopamine (DA). These data demonstrated that TA exerts sedative-hypnotic and anxiolytic effects via binding to the GABAA receptor and activating the monoaminergic system.

The aqueous extract of Albizia adianthifolia leaves attenuates 6-hydroxydopamine-induced anxiety, depression and oxidative stress in rat amygdala

BACKGROUND

While the Albizia adianthifolia (Schumach.) W. Wright (Fabaceae) is a traditional herb largely used in the African traditional medicine as analgesic, purgative, antiinflammatory, antioxidant, antimicrobial, memory-enhancer, anxiolytic and antidepressant drug, there are no scientific data that clarify the anxiolytic and antidepressant-like effects in 6-hydroxydopamine (6-OHDA)-lesioned animal model of Parkinson's disease. This study was undertaken in order to identify the effects of aqueous extract of A. adianthifolia leaves on 6-hydroxydopamine-induced anxiety, depression and oxidative stress in the rat amygdala.

METHODS

The effect of the aqueous extract of A. adianthifolia leaves (150 and 300 mg/kg, orally, daily, for 21 days) on anxiety and depression was assessed using elevated plus-maze and forced swimming tests, as animal models of anxiety and depression. Also, the antioxidant activity in the rat amygdala was assessed using assessed using superoxide dismutase, glutathione peroxidase and catalase specific activities, the total content of the reduced glutathione, protein carbonyl and malondialdehyde levels. Statistical analyses were performed using by one-way analysis of variance (ANOVA). Significant differences were determined by Tukey's post hoc test. F values for which p < 0.05 were regarded as statistically significant. Pearson's correlation coefficient and regression analysis were used in order to evaluate the connection between behavioral measures, the antioxidant defence and lipid peroxidation.

RESULTS

6-OHDA-lesioned rats exhibited the following: decrease of the exploratory activity, the percentage of the time spent and the number of entries in the open arm within elevated plus-maze test and decrease of swimming time and increase of immobility time within forced swimming test. Administration of the aqueous extract significantly exhibited anxiolytic- and antidepressant-like effects and also antioxidant potential in the rat amygdala.

CONCLUSIONS

Our results suggest that the aqueous extract ameliorates 6-OHDA-induced anxiety and depression by attenuation of the oxidative stress in the rat amygdala. These pieces of evidence accentuate its use in traditional medicine.

Evaluation of neuropharmacological effects of aqueous leaf extract of Albizia glaberrima (Leguminosae) in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Albizia glaberrima is a shrub found in the deciduous forest and jungle of the coastal plain of West Africa. Preparations of the plant are used traditionally in the treatment of fever, pain and central nervous system disorders, including epilepsy. This study was conducted to investigate the neuropharmacological effects of the aqueous leaf extract of Albizia glaberrima in mice.

MATERIALS AND METHODS

The hole-board, elevated plus-maze, thiopentone-induced sleep (anxiolytic/sedative-hypnotic), traction, climbing, inclined screen (muscle relaxant), strychnine-, picrotoxin- and pentylenetetrazole (PTZ)-induced convulsion (anticonvulsant) tests were employed in this study.

RESULTS

Albizia glaberrima extract at 200mg/kg significantly increased the duration of head dips (p<0.05) and number of open arms entry (p<0.01) compared with control in the hole-board and elevated plus-maze tests, respectively. At 400mg/kg, Albizia glaberrima extract significantly reduced the number of sectional crossings relative to control. The extract at 400mg/kg significantly (p<0.05) increased the duration of sleep compared with control in the thiopentone-induced hypnosis test. Albizia glaberrima extract at 200mg/kg and diazepam (5mg/kg) significantly (p<0.05, 0.01) increased the post-treatment climbing time and reduced the latency to slide down in the climbing and inclined screen tests, respectively. The extract was not effective in the strychnine-induced seizure model, while in the picrotoxin test Albizia glaberrima extract at 100mg/kg significantly (p<0.05) reduced the duration of convulsion while reducing mortality at 400mg/kg, as was the case with diazepam (2mg/kg). The extract and diazepam significantly (p<0.01, 0.001) increased onset and reduced duration of convulsion, with significant level of protection against convulsion and reduction in mortality in the PTZ-induced seizure model. Preliminary phytochemical screening of the extract revealed the presence of phenols>tannins>saponins>flavonoids. The extract was found to be relatively non-toxic when administered p.o. up to 5000mg/kg and the LD50 was 398.11mg/kg when administered i.p.

CONCLUSIONS

The aqueous leaf extract of Albizia glaberrima possesses dose-dependent anxiolytic/muscle relaxant (low dose) and sedative-hypnotic/anticonvulsant (high dose) activities possibly mediated via enhancement of GABAergic inhibitory actions.

Total saponins from Albizia julibrissin inhibit vascular endothelial growth factor-mediated angiogenesis in vitro and in vivo

Dried stem bark from Albizia julibrissin (AJ) is a highly valued Traditional Chinese Medicine, which has been shown to suppress tumor growth and angiogenesis. Total saponins from AJ (TSAJ) are one of the most bioactive components of AJ extract. The present study evaluated the anti-tumor and anti-angiogenic effects of TSAJ in vitro and in vivo. The anti-angiogenic activity of TSAJ was investigated by measuring the effects on vascular endothelial growth factor (VEGF)-induced proliferation, migration and tube formation of Ea.hy926 endothelial cells in vitro. The expression levels of proteins associated with VEGF-induced angiogenesis were determined by western blotting. Furthermore, in vivo Matrigel™ plug and H22 hepatoma tumor models were used to verify the anti-angiogenic effects of TSAJ. The present study demonstrated that TSAJ significantly inhibited VEGF-mediated endothelial cell proliferation, migration and tube formation of Ea.hy926 cells in vitro. The anti-angiogenic effects of TSAJ were modulated by suppression of phosphorylated-(p-) focal adhesion kinase, p-Akt, and p-extracellular signal-regulated kinase in the VEGF/VEGF receptor 2 (R2) signaling pathway. Furthermore, oral administration of TSAJ significantly inhibited tumor growth and tumor-induced angiogenesis, as well as the formation of functional vessels, in the Matrigel™ plug model. These results suggest that TSAJ may be a potential anti-angiogenic agent that targets the VEGF/VEGFR2 signaling pathway, and inhibits tumor-induced angiogenesis.

Memory-enhancing activities of the aqueous extract of Albizia adianthifolia leaves in the 6-hydroxydopamine-lesion rodent model of Parkinson's disease

Background

Albizia adianthifolia (Schumach.) W. Wright (Fabaceae) is a traditional herb largely used in the African traditional medicine as analgesic, purgative, anti-inflammatory, antioxidant, antimicrobial and memory-enhancer drug. This study was undertaken in order to evaluate the possible cognitive-enhancing and antioxidative effects of the aqueous extract of A. adianthifolia leaves in the 6-hydroxydopamine-lesion rodent model of Parkinson’s disease.

Methods

The effect of the aqueous extract of A. adianthifolia leaves (150 and 300 mg/kg, orally, daily, for 21 days) on spatial memory performance was assessed using Y-maze and radial arm-maze tasks, as animal models of spatial memory. Pergolide - induced rotational behavior test was employed to validate unilateral damage to dopamine nigrostriatal neurons. Also, in vitro antioxidant activity was assessed through the estimation of total flavonoid and total phenolic contents along with determination of free radical scavenging activity. Statistical analyses were performed using two-way analysis of variance (ANOVA). Significant differences were determined by Tukey’s post hoc test. F values for which p < 0.05 were regarded as statistically significant. Pearson’s correlation coefficient and regression analysis were used in order to evaluate the association between behavioral parameters and net rotations in rotational behavior test.

Results

The 6-OHDA-treated rats exhibited the following: decrease of spontaneous alternations percentage within Y-maze task and increase of working memory errors and reference memory errors within radial arm maze task. Administration of the aqueous extract of A. adianthifolia leaves significantly improved these parameters, suggesting positive effects on spatial memory formation. Also, the aqueous extract of A. adianthifolia leaves showed potent in vitro antioxidant activity. Furthermore, in vivo evaluation, the aqueous extract of A. adianthifolia leaves attenuated the contralateral rotational asymmetry observed by pergolide challenge in 6-OHDA-treated rats.

Conclusions

Taken together, our results suggest that the aqueous extract of A. adianthifolia leaves possesses antioxidant potential and might provide an opportunity for management neurological abnormalities in Parkinson’s disease conditions.

Luteolin mediates the antidepressant-like effects of Cirsium japonicum in mice, possibly through modulation of the GABAA receptor

Cirsium japonicum (CJ) has been shown to possess antidepressant-like properties. In the present study, we sought to identify which constituent of CJ might be responsible for its antidepressant effects and determine probable mechanism of action. The ethanol extract of CJ was administered to mice then behavioral changes were evaluated in the forced-swimming test (FST) and open-field test (OFT). In addition, its effects on norepinephrine (NE) reuptake and intracellular chloride (Cl(-)) flux were determined, in vitro. The effects of CJ's major constituents (linarin, pectolinarin, chlorogenic acid, luteolin) were also evaluated. CJ showed antidepressant-like effect by significantly reducing immobile behavior of mice in the FST, without increasing locomotor activity in the OFT. CJ had no effect on monoamine (NE) uptake, but it significantly promoted Cl(-) ion influx in human neuroblastoma cells. This CJ-induced Cl(-) influx was significantly blocked by co-administration of the competitive GABAA receptor antagonist, bicuculline. Among the major constituents of the CJ extract, only luteolin produced similar antidepressant-like effect, in vivo, and Cl(-) ion influx, in vitro. Altogether, the present results suggest that the antidepressant-like effect of CJ was most probably induced by its constituent luteolin, mediated through potentiation of the GABAA receptor-Cl(-) ion channel complex.