Potential Anxiolytic Activity Research Articles

The Study of Myo-Inositol's Anxiolytic Activity on Zebrafish (Danio rerio).

Myo-inositol (MI) is the most abundant inositol found in nature. To date MI supplementation is reported to be effective in the treatment of polycystic ovary syndrome, it is also suggested to alleviate the symptoms of diabetes and neurodegenerative disorders, but to date no statistically significant effects of inositol on depressive and anxiety symptoms were proven. In the study of anxiolytic effects in zebrafish, we often use the thigmotaxis index measuring the ratio of the amount of time the animal spends near the walls compared to the entire arena. The objective of this paper was to examine the effect of MI on zebrafish embryos' locomotor activity, as well as its potential anxiolytic activity in zebrafish larvae. In the first part of the experiment, the embryos were incubated with 5, 10, 20, and 40 mg/mL MI. 1-day post fertilization, embryo mobility was evaluated and burst activity was calculated. In the next part of the study, the behavior of 5-day-old larvae was tested. Tests on embryo movement showed an increase in burst activity in the MI group at concentrations of 40 mg/mL (p < 0.0001) and a slight decrease in the group at concentrations of 10 mg/mL (p < 0.05). MI in the light/dark challenge had no impact on the thigmotaxis index. MI was shown to not affect stress reduction in zebrafish larvae. Further research on the potential of MI and other stereoisomers is needed.

Chemical profiling, anticonvulsant and anxiolytic effects of the smoke constituents isolated from Leonotis leonurus (L.) R.Br.

Ethnopharmacological relevanceThe use of medicinal plants for central nervous system (CNS)-related ailments, such as epilepsy and anxiety, is prevalent in South Africa. Plants from the Lamiaceae family are commonly used for their therapeutic benefits. Leonotis leonurus (L.) R.Br. has been reported in ethnobotanical literature to have anticonvulsant and anxiolytic effects through the inhalation of pyrolysis products obtained by combustion of the aerial parts. Aim and objectivesTo explore the chemical profiles and CNS activity of the smoke extract and isolated constituents of L. leonurus in zebrafish larvae, through anticonvulsive and anxiolytic activity assays. Materials and methodsThe smoke extract of L. leonurus was obtained through the combustion of the aerial parts of the plant using a custom-built smoke recovery apparatus. The chemical profile of the smoke constituents was determined using Ultra-Performance Liquid Chromatography coupled with Mass Spectrometry (UPLC-MS). Targeted compounds were subjected to preparative High-Performance Liquid Chromatography for separation before structure elucidation using Nuclear Magnetic Resonance (NMR). The maximum tolerated concentrations, as well as the anxiolytic activity of the smoke extract were determined in five days post fertilisation zebrafish larvae. Reverse-thigmotaxis and locomotor activity of larvae in the light/dark transition assay were used to determine anxiolytic activity. Zebrafish larvae at six days post fertilisation (dpf) were subjected to several concentrations of the smoke constituents of L. leonurus. The baseline locomotor activity of the larvae was tracked for 30 min, prior to addition of pentylenetetrazole (PTZ) to induce seizure-like behaviour in the larvae, after which the locomotor activity of the larvae was once again tracked for an additional 30 min. ResultsThe UPLC-MS profiles of the smoke extract revealed the presence of two main compounds, leoleorin A and leoleorin B, which were targeted and isolated. Upon subjection to NMR spectroscopy for structure elucidation, the compounds were confirmed to be labdane diterpenoids. Both leoleorin A and leoleorin B, and the smoke extract displayed suppression of the PTZ induced seizure-like behaviour in zebrafish larvae. Under light and dark conditions, the smoke extract and compounds displayed potential anxiolytic activity at different concentrations. ConclusionOur results suggest that the smoke constituents of L. leonurus may exert anticonvulsant and anxiolytic effects which align with the traditional indications and the mode of administration.

Clove volatile oil-loaded nanoemulsion reduces the anxious-like behavior in adult zebrafish.

Clove volatile oil (CVO) and its major compound, eugenol (EUG), have anxiolytic effects, but their clinical use has been impaired due to their low bioavailability. Thus, their encapsulation in nanosystems can be an alternative to overcome these limitations. This work aims to prepare, characterize and study the anxiolytic potential of CVO loaded-nanoemulsions (CVO-NE) against anxious-like behavior in adult zebrafish (Danio rerio). The CVO-NE was prepared using Agaricus blazei Murill polysaccharides as stabilizing agent. The drug-excipient interactions were performed, as well as colloidal characterization of CVO-NE and empty nanoemulsion (B-NE). The acute toxicity and potential anxiolytic activity of CVO, EUG, CVO-NE and B-NE against adult zebrafish models were determined. CVO, EUG, CVO-NE and B-NE presented low acute toxicity, reduced the locomotor activity and anxious-like behavior of the zebrafish at 4 - 20mgkg-1. CVO-NE reduced the anxious-like behavior of adult zebrafish without affecting their locomotor activity. In addition, it was demonstrated that anxiolytic activity of CVO, EUG and CVO-NE is linked to the involvement of GABAergic pathway. Therefore, this study demonstrates the anxiolytic effect of CVO, in addition to providing a new nanoformulation for its administration.

Glucosyl hesperidin exhibits more potent anxiolytic activity than hesperidin accompanied by the attenuation of noradrenaline induction in a zebrafish model.

Anxiety is a symptom of various mental disorders, including depression. Severe anxiety can significantly affect the quality of life. Hesperidin (Hes), a flavonoid found in the peel of citrus fruits, reportedly has various functional properties, one of which is its ability to relieve acute and chronic stress. However, Hes is insoluble in water, resulting in a low absorption rate in the body and low bioavailability. Glucosyl hesperidin (GHes) is produced by adding one glucose molecule to hesperidin. Its water solubility is significantly higher than that of Hes, which is expected to improve its absorption into the body and enhance its effects. However, its efficacy in alleviating anxiety has not yet been investigated. Therefore, in this study, the anxiolytic effects of GHes were examined in a zebrafish model of anxiety. Long-term administration of diets supplemented with GHes did not cause any toxicity in the zebrafish. In the novel tank test, zebrafish in the control condition exhibited an anxious behavior called freezing, which was significantly suppressed in GHes-fed zebrafish. In the black-white preference test, which also induces visual stress, GHes-fed zebrafish showed significantly increased swimming time in the white side area. Furthermore, in tactile (low water-level stress) and olfactory-mediated stress (alarm substance administration test) tests, GHes suppressed anxious behavior, and these effects were stronger than those of Hes. Increased noradrenaline levels in the brain generally cause freezing; however, in zebrafish treated with GHes, the amount of noradrenaline after stress was lower than that in the control group. Activation of c-fos/ERK/Th, which is upstream of the noradrenaline synthesis pathway, was also suppressed, while activation of the CREB/BDNF system, which is vital for neuroprotective effects, was significantly increased. These results indicate that GHes has a more potent anxiolytic effect than Hes in vivo, which may have potential applications in drug discovery and functional food development.

New insights on the phytochemical intervention for the treatment of neuropsychiatric disorders using the leaves of Michelia champaca: an in vivo and in silico approach

Context Michelia champaca L. (Magnoliaceae) has been known since ancient times for its rich medicinal properties. Objective The ethanol extract of Michelia champaca leaves (EEMC) was evaluated on depression and anxiety using in vivo and in silico studies Materials and methods Swiss albino mice were divided into control, standard, 100 and 200 mg/kg b.w. EEMC groups and for drug administration using oral gavage. The antidepressant activity was evaluated using forced swim test (FST) and tail suspension test (TST) whereas the anxiolytic activity through elevated plus maze and light and dark tests. The in silico studies included molecular docking against human potassium channel KCSA-FAB and human serotonin transporter, and ADME/T analysis. Results Open arm duration and entries were comparable between 200 mg/kg b.w. group (184.45 ± 1.00 s and 6.25 ± 1.11, respectively) and that of diazepam treated group (180.02 s ± 0.40 and 6.10 ± 0.05, respectively). Time spent in the light cubicle was higher (46.86 ± 0.03%), similar to that of diazepam (44.33 ± 0.64%), suggesting its potent anxiolytic activity. A delayed onset of immobility and lowered immobility time was seen at both the treatment doses (FST: 93.7 ± 1.70 and 89.1 ± 0.40 s; TST: 35.05 ± 2.75 and 38.50 ± 4.10 s) and the standard drug imipramine (FST: 72.7 ± 3.72 and TST: 30.01 ± 2.99 s), indicative of its antidepressant ability. In silico studies predicted doripenem to induce anxiolytic and antidepressant activity by inhibiting human potassium channel KCSA-FAB and human serotonin transporter proteins, respectively. Conclusions EEMC is a rich source of bioactive compounds with strong antidepressant and anxiolytic properties.

Escitalopram alters local expression of noncanonical stress-related neuropeptides in the rat brain via NPS receptor signaling.

Neuropeptide S (NPS) is a multifunctional regulatory factor that exhibits a potent anxiolytic activity in animal models. However, there are no reports dealing with the potential molecular relationships between the anxiolytic activity of selective serotonin reuptake inhibitors (SSRIs) and NPS signaling, especially in the context of novel stress-related neuropeptides action. The present work therefore focused on gene expression of novel stress neuropeptides in the rat brain after acute treatment with escitalopram and in combination with neuropeptide S receptor (NPSR) blockade. Studies were carried out on adult, male Sprague-Dawley rats that were divided into five groups: animals injected with saline (control) and experimental rats treated with escitalopram (at single dose 10mg/kg daily), escitalopram and SHA-68, a selective NPSR antagonist (ata single doseof 40mg/kg), SHA-68 alone and corresponding vehicle (solvent SHA-68) control. To measure anxiety-like behavior and locomotor activity the open field test was performed. All individuals were killed under anaesthesia and the whole brainwas excised. Total mRNA was isolated from homogenized samples ofthe amygdala, hippocampus, hypothalamus, thalamus, cerebellum, and brainstem. Real-time PCR was used for estimation of related NPS, NPSR, neuromedin U (NMU), NMU receptor 2 (NMUR2) and nesfatin-1 precursor nucleobindin-2 (NUCB2) gene expression. Acute escitalopram administration affects the local expression of the examined neuropeptides mRNA in a varied manner depending on brain location. An increase in NPSR and NUCB2 mRNA expression in the hypothalamus and brainstem was abolished by SHA-68 coadministration, while NMU mRNA expression was upregulated after NPSR blockade in the hippocampus and cerebellum. The pharmacological effects of escitalopram may be connected with local NPSR-related alterations in NPS/NMU/NMUR2 and nesfatin-1 gene expression at the level of selected rat brain regions. A novel alternative mode of SSRI action can be therefore cautiously proposed.

Effect of Escitalopram on the Number of DCX-Positive Cells and NMUR2 Receptor Expression in the Rat Hippocampus under the Condition of NPSR Receptor Blockade.

Background: Neuropeptide S (NPS) is a multifunctional regulatory factor that exhibits a potent anxiolytic activity in animal models. However, there are no reports dealing with the potential molecular interactions between the activity of selective serotonin reuptake inhibitors (SSRIs) and NPS signaling, especially in the context of adult neurogenesis and the expression of noncanonical stress-related neuropeptides such as neuromedin U (NMU). The present work therefore focused on immunoexpression of neuromedin U receptor 2 (NMUR2) and doublecortin (DCX) in the rat hippocampus after acute treatment with escitalopram and in combination with selective neuropeptide S receptor (NPSR) blockade. Methods: Studies were carried out on adult, male Sprague-Dawley rats that were divided into five groups: animals injected with saline (control) and experimental individuals treated with escitalopram (at single dose 10 mg/kg daily), escitalopram + SHA-68, a selective NPSR antagonist (at single dose 40 mg/kg), SHA-68 alone, and corresponding vehicle control. All animals were sacrificed under halothane anaesthesia. The whole hippocampi were quickly excised, fixed, and finally sliced for general qualitative immunohistochemical assessment of the NPSR and NMUR2 expression. The number of immature neurons was enumerated using immunofluorescent detection of doublecortin (DCX) expression within the subgranular zone (SGZ). Results: Acute escitalopram administration affects the number of DCX and NMUR2-expressing cells in the adult rat hippocampus. A decreased number of DCX-expressing neuroblasts after treatment with escitalopram was augmented by SHA-68 coadministration. Conclusions: Early pharmacological effects of escitalopram may be at least partly connected with local NPSR-related alterations of neuroblast maturation in the rat hippocampus. Escitalopram may affect neuropeptide and DCX-expression starting even from the first dose. Adult neurogenesis may be regulated via paracrine neuropeptide S and NMU-related signaling.

Scutellarin ameliorates the stress-induced anxiety-like behaviors in mice by regulating neurotransmitters.

Anxiety disorders are a common frequently psychiatric symptom in patients that lead to disruption of daily life. Scutellarin (Scu) is the main component of Erigeron breviscapus, which has been used as a neuroprotective agent against glutamate-induced excitotoxicity. However, the potential effect of Scu on the stress-related neuropsychological disorders has not been clarified. In this study, Anxiety-like behavior was induced by acute restraint stress in mice. Scu were injected intraperitoneally (twice daily, 3 days). Results showed that Scu exhibited good protective activity on mice by decreasing transmitter release levels. Restraint stress caused significant anxiety like behavior in mice. Treatment of Scu could significantly improve the moving time of open arms in Elevated Plus Maze and central time on open field test. Scu treatment suppressed action potential firing frequency, restored excessive presynaptic quantal release, and down-regulated glutamatergic receptor expression levels in the prefrontal cortex (PFC) of stressed mice. GABAA Rα1 and GABAA γ2 expression in the brain PFC tissues of mice were nearly abrogated by Scu treatment. In stress-induced anxiety mice, stress can increase the frequency of mini excitatory postsynaptic currents (mEPSC), which can be reversed by Scu treatment. Therefore, Scu has a potent anxiolytic activity and may be valuable for the treatment of stress-induced anxiety disorders.

Coumarins from Seseli devenyense Simonk.: Isolation by Liquid-Liquid Chromatography and Potential Anxiolytic Activity Using an In Vivo Zebrafish Larvae Model.

Different types of anxiety disorders have become the number one mental health issue in developed countries. The search for new, safer and effective drug-like molecules among naturally derived substances faces two difficulties: an efficient method of isolation compounds with a high-purity and high-throughput animal model for activity assay. Thus, the aim of the present study was to isolate by liquid–liquid chromatography high-purity rare coumarins from the fruits of Seseli devenyense Simonk. and evaluate their anxiolytic effect (defined as reversed thimotaxis) using a 5-days post-fertilization (dpf) Danio rerio larvae model. Liquid–liquid chromatography enabled the isolation of one simple hydroxycoumarin (devenyol) and four pyranocoumarins (cis-khellactone, d-laserpitin, isolaserpitin and octanoyllomatin). The anxiolytic effect was defined as a decrease in the time spent in the boundaries of the living space (also described as reversed thigmotaxis). Our results show that all isolated courmarins exerted a significant influence on the anxiety behavior (anxiolytic activity) in the zebrafish larvae model. According to our knowledge, this is the first report of anxiolytic activity of pyranocoumarins and devenyol.

Screening selected medicinal plants for potential anxiolytic activity using an in vivo zebrafish model.

Medicinal plants are used extensively in many countries to treat conditions related to the central nervous system (CNS), and there is renewed interest to explore natural products, which may exhibit CNS activity. In this study, seven plants were selected based on literature reports of their ethnopharmacological use in treating anxiety-related conditions and assayed in a zebrafish model. Crude extracts were prepared with solvents of different polarities, and the maximum tolerated concentration (MTC) of these crude extracts was established. The anxiolytic activity of the crude extracts was determined using 5-day post-fertilization (dpf) zebrafish larvae. General locomotor activity and reverse-thigmotaxis behavior (indicative of anxiolytic activity) were analyzed under continuous illumination and alternating light-dark challenges, which induced anxiety in the zebrafish larvae. Of the 28 extracts tested, 13 were toxic according to the MTC values obtained. Larvae were subsequently treated with the 15 non-toxic extracts, at a dose determined in the MTC assay or with 1% DMSO as control. The anxiolytic activity (reverse-thigmotaxis) was demonstrated by an increase in the percentage time spent by the larvae in the central arena of the well. Of the 15 non-toxic extracts tested, the Sceletium tortuosum water extract exhibited the most promising anxiolytic activity. The zebrafish model was effective in studying anxiety-related behavior. Thus, the study confirmed that S. tortuosum mitigates anxiety in zebrafish larvae, a step towards the full in vivo validation of the traditional use of the plant.

Anxiolytic and anti-depressant effects of hydroalcoholic extract from Erythrina variegata and its possible mechanism of action.

Erythrina variegata has been widely used as a traditional medicine. The study was designed to evaluate the anxiolytic and anti-depressant effects of an extract from Erythrina variegata. The extract was evaluated for anxiolytic and anti-depressant action using the elevated plus maze, light/dark box, open field, forced swimming and tail suspension tests in mice. The mechanism of action was further elucidated using high-performance liquid chromatography with fluorescence detection methods to assay the levels of five neurotransmitters in brain. The extract exhibited significant increase in the percentage of the open arms entries and the time spent in the open arms in the elevated plus maze test. The results of the light/dark box test revealed a significant increase in the amount of time spent in the light chamber. Extract- treated mice also produced significant increase in the number of crossings and rearings in the open field test. In the forced swimming and tail suspension tests, the extract was able to promote significant decrease in the immobility time. In addition, the extract significantly altered the levels of five neurotransmitters in the brain tissue. These findings suggest that Erythrina variegata presents potential anxiolytic and anti-depressant activity, and the mechanism may be related to the alteration of neurotransmitter levels.

Anxiolytic Effect of Cedrol on Behavior and Brain Neurotransmitter Levels of Female Mice

Cedrol has been reported to be effective in reducing anxiety of male mice. The limited application of females in animal models of anxiety makes it difficult to systematically investigate new drug substitutes with potential anxiolytic activity. In the present study, we investigated the behavioral response of female ICR mice to cedrol after intraperitoneal (i.p.) administration using the elevated plus maze (EPM) and the light-dark box (LDB) test, followed by determination of neurochemical changes in brain. The data suggested that cedrol at dose of 1200-1600 mg·kg-1 exhibited anxiolytic activity on the female mice, as reflected by greater percentage of entries into the open arms and time spent in the open arms in the EPM, and greater transitions between chambers and percentage of time spent in the light chamber in the LDB. Cedrol increased the level of 5-hydroxytryptamine (5-HT), decreased the level of dopamine (DA), reduced the ratio of 5-hydroxyindoleacetic acid (5-HIAA)/5-HT and increased the ratio of 3,4-dihydroxyphenyl acetic acid (DOPAC)/DA, compared with the control group, indicative of an anxiolytic-like effect on female mice via the 5-HTnergic or DAnergic pathways.

Anxiolytic and hypnotic effects of Cocculus laurifolius leaf extract in mice

The present study aims to assess the anxiolytic and hypnotic activity of ethanolic extract of Cocculus laurifolius leaf in mice. Anxiolytic activity was observed using behavioral paradigms while hypnotic activity was assessed by sodium pentobarbital induced hypnosis in mice. Animals were treated with the extract at dose 200 and 400 mg/kg orally for 30 days. Anxiolytic and hypnotic effect were observed on day 1, 7, 15 and 30 of treatment. Significant increase in the number of entries and time spent in open arm were observed in elevated plus maze. Similar results were observed in light/dark, open field and hole board test. The anxiolytic effect was substantially greater at dose 200 mg/kg in comparison to dose 400 mg/kg. Minimal hypnotic activity was observed with decrease in onset and prolongation in duration of sleep at dose 400 mg/kg, while dose 200 mg/kg did not produce any hypnotic effect. These results showed that the ethanolic extract of C. laurifolius leaf might have potential anxiolytic and hypnotic activity in mice.

Evaluation of Anxiolytic and Sedative-Like Activities of Methanolic Extract of &amp;lt;i&amp;gt;Euphorbia hirta&amp;lt;/i&amp;gt; Leaves in Mice

In indigenous or folk medicine, Euphorbia hirta is a very popular herb and used as a palliative to treat various ailments including intestinal parasites, diarrhoea, vomiting, amoebic dysentery, asthma, bronchitis, emphysema, coughs, kidney stones, menstrual problems etc. The objective of this study is to evaluate the anxiolytic and sedative-like effects of the methanol extract from the leaves of Euphorbia hirta (Euphorbiaceae). Methanolic extract of Euphorbia hirta was evaluated for its CNS depression effect using mice behavioral models such as, elevated plus maze and hole board test for its anxiolytic potential where hole cross and pentobarbital-induced sleeping time tests were performed for its sedative properties, respectively. The test group received three different doses of the MEHL (100 mg/kg, 200 mg/kg and 300 mg/kg) orally. The positive control group received diazepam (1 mg/kg) orally where the negative control group received distilled water (10 ml/kg) orally. In elevated plus maze test, the extract exhibited significant (p < 0.05) increased the number of open arm entry and time spent in open arm by mice compared to control group. In addition, the number of head dips and hole crosses significantly (p < 0.05) decreased by mice in hole board and hole cross tests respectively, compared to control group. Moreover, mice treated with MEHL significantly decrease the onset of sleep and increase the duration of sleep in pentobarbital-induced sleeping time test in mice compared to control group. The data obtained from the present study clearly demonstrate that the methanolic extract of Euphorbia hirta has potential anxiolytic and sedative-like activity in the animal behavioral models. And the findings represent a rational explanation for its use in traditional medicine for the management of neurological disorder.

Evaluation of anxiolytic activity of W. chinensis Merrill leaves

Wedelia chinensis (family: Asteraceae), commonly known as Pilabhangra has been traditionally used for the treatment of various ailments like jaundice, diarrhoea, cephalahagia, respiratory disorders and to induce sleep, reduce the mental tension and in anxiety. Despite a long history of uses, no scientific pharmacological evaluation has ever been carried out on this plant. Thus, the present study was designed to evaluate anxiolytic activity of W. chinensis using different models of anxiety. Hydro-alcohol extract of W. chinensis leaves was prepared and subjected to bioactivity guided fractionation. Antioxidant activity was determined by spectrophotometric method. Total phenolic and flavonoid content were also estimated. Amongst the various fractions/extract of W. chinensis tested, only hydro-alcoholic extract, and its ethyl acetate fraction exhibited significant (P&lt;0.05) anxiolytic activity in mice using elevated plus maze and light-dark box model of anxiety at a dose of 200 mg/kg and 100 mg/kg respectively. Among the various fractions tested, maximum anxiolytic activity was observed only in ethyl acetate fraction which was at par with that of diazepam. The results of present investigation provide evidence that ethyl acetate fraction of hydro-alcoholic extract of W. chinensis has potent anxiolytic activity supporting the traditional claim of W. chinensis in the treatment of anxiety.

Solid-State Form Characterization of Riparin I.

Riparin I is an alkamide with potential anxiolytic activity in preclinical studies. The characterization and understanding of solid-state properties play an importance role in drug development. For this work, the solid state of five riparin I batches (RIP-1, RIP-2, RIP-3, RIP-4, and RIP-5), obtained by the same synthesis process, were characterized by Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), DSC-photovisual, Thermogravimetry (TG), Fourier Transform Infrared (FTIR), Pyrolysis (Pyr-GC/MS), X-ray Powder Diffraction (PXRD), and Solid-State Nuclear Magnetic Resonance (ssNMR) techniques. Batches of riparin I with different crystal habits resulting in crystallization impurities were observed, which can be attributed to the presence of triethylamine. The main differences were observed by DSC, PXRD, and ssNMR analysis. DSC curves of RIP-2 and RIP-3 presented endothermic peaks at different temperatures of fusion, which can be attributed to the mixture of different crystalline forms. PXRD and ssNMR results confirmed crystallinity differences. The results offer evidence of the importance of controlling the reproducibility of the synthesis in order to obtain the adequate morphology for therapeutic efficacy and avoiding future problems in quality control of riparin I products.

Bioactivity Guided Isolation, Characterization and Quantification of an Anxiolytic Constituent - Kaempferol, from Melilotus officinalis Aerial Parts

Numerous plants used in traditional system of medicine exhibit pharmacological properties with great potential for therapeutic applications in the treatment of anxiety disorders. The aerial parts of Melilotus officinalis (Fabaceae) have been used traditionally for the treatment of convulsions, insomnia and as a nervine tonic. Despite a long tradition of its use in nervous system disorders, no systematic phytochemical and pharmacological work has been carried out on this potential plant. The aim of the present study was to isolate the antianxiety constituent(s) from M. officinalis aerial parts following bioactivity guided fractionation approach. Ethanol extract was partitioned successively with ethyl acetate and butanol and all fractions were evaluated for antianxiety activity. The bioactive ethyl acetate fraction was further subjected to column chromatography to get seven fractions which were evaluated for antianxiety effect in elevated plus maze (EPM). The bioactive EAF6 when subjected to column chromatography resulted in isolation of a flavonoid, which was characterized by standard spectral techniques and its anxiolytic activity was evaluated using EPM and mirror chamber model. TLC densitometric method was developed to quantify the isolated compound. The present study resulted in isolation of kaempferol, which exhibits potent anxiolytic activity at 2 mg/kg which was comparable to that of diazepam. The study validates the traditional use of the M. officinalis aerial parts as an anxiolytic. Kaempferol was found to be responsible for anxiolytic effect of M. officinalis aerial parts.

Further evaluation of the potential anxiolytic activity of imidazo[1,5-a][1,4]diazepin agents selective for α2/3-containing GABAA receptors

Positive allosteric modulators of GABAA receptors transduce a host of beneficial effects including anxiolytic actions. We have recently shown that bioavailability and anxiolytic-like activity can be improved by eliminating the ester functionality in imidazo[1,5-a][1,4]diazepines. In the present series of experiments, we further substantiate the value of heterocyle replacement of the ester for potential treatment of anxiety. None of three esters was active in a Vogel conflict test in rats that detects anxiolytic drugs like diazepam. Compounds 7 and 8, ester bioisosters, were selective for alpha 2 and 3 over alpha 1-containing GABAA receptors but also had modest efficacy at GABAA alpha 5-containing receptors. Compound 7 was efficacious and potent in this anxiolytic-detecting assay without affecting non-punished responding. The efficacies of the esters and of compound 7 were predicted from their efficacies as anticonvulsants against the GABAA antagonist pentylenetetrazole (PTZ). In contrast, the related structural analog, compound 8, did not produce anxiolytic-like effects in rats despite anticonvulsant efficacy. These data thus support the following conclusions: 1) ancillary pharmacological actions of compound 8 might be responsible for its lack of anxiolytic-like efficacy despite its efficacy as an anticonvulsant 2) esters of imidazo[1,5-a][1,4]diazepines do not demonstrate anxiolytic-like effects in rats due to their low bioavailability and 3) replacement of the ester function with suitable heterocycles markedly improves bioavailability and engenders molecules with the opportunity to have potent and efficacious effects in vivo that correspond to human anxiolytic actions.

SCREENING ANXIOLYTIC ACTIVITIES OF METHANOLIC FRUIT EXTRACTS OF SPONDIA PINNATA PLANT

This Present study was surpassed to investigate t he methanolic extracts of Spondias pinnata fruit for anxio lytical activities. S. pinnata is a plant of Anacardiacea family. The methanolic crude extract were scr eened for a nxiolytic activities using h ole board test met hod (***p < 0.001) and elevated plus maze t est method (***p < 0.001) in mice. Test results found 40.25±2.98 times for 400mg/ml extract in hole - board and 152.5±44. 78, 147.5±, 9.25±1.79 times in elevated plus maze r espectively as comparison with standard. The use of crude extracts of fruits of Spondias pinnata as anxiolytics have been confirmed that the fruits extracts displayed potential anxiolytic activity against mice for head dipping and stay in open and enclosed arms in the study. Various concentrations of extracts were tested and results were expressed in terms of time. In conclusion, the methanol extract of the fruits and plant of Spondias pin nata displayed anxiolytic activity.

PRELIMINARY STUDIES ON THE BEHAVIOURAL EFFECTS OF THE METHANOL EXTRACT OF LEONOTIS NEPETIFOLIA LINN STEM IN MICE.

Background:Leonotis nepetifolia Linn (Lamiaceae) is used in traditional medicine for its calming (tranquilizing) effects. The aim of this study was to determine whether there is any scientific justification for this use. To achieve this purpose, we investigated the behavioural effects of the methanol extract of Leonotis nepetifolia stem (37.5, 75 and 150 mg/kg) in mice.Methods:Acute toxicity studies were carried out on the methanol stem extract of Leonotis nepetifolia to determine the LD50. The behavioural tests employed were diazepam-induced sleep onset and duration, hole board assay for exploratory activity, mouse beam walk assay for motor coordination, and the staircase test for the detection of anxiolytic compounds. Preliminary phytochemical screening was also carried out on the extract.Results:The intraperitoneal LD50 value was found to be 3.8 g/kg. The results showed that the extract significantly prolonged the duration of diazepam-induced sleep at the highest dose (150 mg/kg). There was no observable effect on exploratory activity and motor coordination at the doses tested (37.5, 75 and 150 mg/kg). The extract, however, at 150 mg/kg elicited a significant decrease in the number of rearings in the staircase test, an effect also observed in the group of mice injected with an anxiolytic dose of diazepam. The preliminary phytochemical screening revealed the presence of alkaloids, saponins, glycosides and triterpenoids.Conclusion:The results obtained suggest that the crude methanol extract of Leonotis nepetifolia stem possesses some biologically active constituents with potential anxiolytic activity and thus may justify its traditional use as a tranquilizer.