Withania somnifera influences MDMA-induced hyperthermic, cognitive, neurotoxic and neuroinflammatory effects in mice

Withania somnifera (WS) is utilized in Ayurvedic medicine owing to its central and peripheral beneficial properties. Several studies have accrued indicating that the recreational amphetamine-related drug (+/-)- 3,4-methylenedioxymethamphetamine (MDMA; Ecstasy) targets the nigrostriatal dopaminergic system in mice, inducing neurodegeneration and gliosis, causing acute hyperthermia and cognitive impairment. This study aimed to investigate the effect of a standardized extract of W. somnifera (WSE) on MDMA-induced neurotoxicity, neuroinflammation, memory impairment and hyperthermia. Mice received a 3-day pretreatment with vehicle or WSE. Thereafter, vehicle- and WSE-pretreated mice were randomly divided into four groups: saline, WSE, MDMA alone, WSE plus MDMA. Body temperature was recorded throughout treatment, and memory performance was assessed by a novel object recognition (NOR) task at the end of treatment. Thereafter, immunohistochemistry was performed to evaluate in the substantia nigra pars compacta (SNc) and striatum the levels of tyrosine hydroxylase (TH), as marker of dopaminergic degeneration, and of glial fibrillary acidic protein (GFAP) and TMEM119, as markers of astrogliosis or microgliosis, respectively. MDMA-treated mice showed a decrease in TH-positive neurons and fibers in the SNc and striatum respectively, an increase in gliosis and body temperature, and a decrease in NOR performance, irrespective of vehicle or WSE pretreatment. Acute WSE plus MDMA counteracted the modifications in TH-positive cells in SNc, GFAP-positive cells in striatum, TMEM in both areas and NOR performance, as compared to MDMA alone, while no differences were observed as compared to saline. Results indicate that WSE acutely administered in combination with MDMA, but not as pretreatment, protects mice against the noxious central effects of MDMA.

The biologically active compound of Withania somnifera (L.) Dunal, docosanyl ferulate, is endowed with potent anxiolytic properties but devoid of typical benzodiazepine-like side effects

BACKGROUND

Clinical and experimental studies support the therapeutic potential of Withania somnifera (WS) (L.) Dunal on anxiety disorders. This potential is attributable to components present in different plant extracts; however, the individual compound(s) endowed with specific anxiolytic effects and potential modulatory activity of the GABAA receptor complex (GABAAR) have remained unidentified until the recent isolation from a WS methanolic root extract of some GABAAR-active compounds, including the long alkyl-chain ferulic acid ester, docosanyl ferulate (DF).

AIMS

This study was designed to assess whether DF (0.05, 0.25 and 2 mg/kg), similarly to diazepam (2 mg/kg), may exert anxiolytic effects, whether these effects may be significantly blocked by the benzodiazepine antagonist flumazenil (10 mg/kg) and whether DF may lack some of the benzodiazepines' typical motor, cognitive and motivational side effects.

METHODS

The behavioural paradigms Elevated Plus Maze, Static Rods, Novel Object Recognition, Place Conditioning and potentiation of ethanol-induced Loss of Righting Reflex were applied on male CD-1 mice.

RESULTS

Similarly to diazepam, DF exerts anxiolytic effects that are blocked by flumazenil. Moreover, at the full anxiolytic dose of 2 mg/kg, DF lacks typical benzodiazepine-like side effects on motor and cognitive performances and on place conditioning. Moreover, DF fails to potentiate ethanol's (3 g/kg) depressant activity at the ethanol-induced Loss of Righting Reflex paradigm.

CONCLUSIONS

These data point to DF as an effective benzodiazepine-like anxiolytic compound that, in light of its lack of motor, mnemonic and motivational side effects, could be a suitable candidate for the treatment of anxiety disorders.

Inhibition of Morphine- and Ethanol-Mediated Stimulation of Mesolimbic Dopamine Neurons by Withania somnifera

Morphine- and ethanol-induced stimulation of neuronal firing of ventral tegmental area (VTA) dopaminergic neurons and of dopamine (DA) transmission in the shell of the nucleus accumbens (AcbSh) represents a crucial electrophysiological and neurochemical response underlying the ability of these compounds to elicit motivated behaviors and trigger a cascade of plasticity-related biochemical events. Previous studies indicate that the standardized methanolic extract of Withania somnifera roots (WSE) prevents morphine- and ethanol-elicited conditioned place preference and oral ethanol self-administration. Aim of the present research was to investigate whether WSE may also interfere with the ability of morphine and ethanol to stimulate VTA dopaminergic neurons and thus AcbSh DA transmission as assessed in male Sprague-Dawley rats by means of patch-clamp recordings in mesencephalic slices and in vivo brain microdialysis, respectively. Morphine and ethanol significantly stimulated spontaneous firing rate of VTA neurons and DA transmission in the AcbSh. WSE, at concentrations (200-400 μg/ml) that significantly reduce spontaneous neuronal firing of VTA DA neurons via a GABA_A- but not GABA_B-mediated mechanism, suppressed the stimulatory actions of both morphine and ethanol. Moreover, in vivo administration of WSE at a dose (75 mg/kg) that fails to affect basal DA transmission, significantly prevented both morphine- and ethanol-elicited increases of DA in the AcbSh. Overall, these results highlight the ability of WSE to interfere with morphine- and ethanol-mediated central effects and suggest a mechanistic interpretation of the efficacy of this extract to prevent the motivational properties of these compounds.

Protective Effect of Standardized Extract of Passiflora incarnata Flower in Parkinson's and Alzheimer's Disease

Background:

Oxidative stress plays an important role in the pathogenesis of neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease. Flavonoids exert their antioxidant effects by neutralizing all types of oxidizing radicals including the superoxide and hydroxyl radicals. Passiflora incarnata Linn. (Passifloraceae) is an important plant used in Ayurveda for the treatment of various disorders of the CNS and is a rich source of flavonoids.

Aim:

In the present study, we investigated the antioxidant, antiparkinsonian, and memory enhancing activity of flavonoid rich n-butanol extract of P. incarnata flowers (BEPIF).

Materials and Methods:

Antioxidant activity was assessed using DPPH and hydrogen peroxide scavenging assay. The antiparkinsonian activity was evaluated using haloperidol induced catalepsy and tacrine induced vacuous chewing movement and memory enhancing activity was assessed using elevated plus maze and object recognition test.

Statistical Analysis:

The results were analyzed by Analysis of Variance test followed by Dunnett’s test.

Results:

Administration of BEPIF decreased transfer latency on day 2 and 9 significantly in elevated plus maze test and showed a significant increase in discrimination index in the object recognition test which is suggestive of its cognitive improvement action. Pretreatment with BEPIF showed a significant reduction in the haloperidol induced catalepsy and the tacrine induced jaw movements which are suggestive of its antiparkinsonian activity. In DPPH and H₂O₂ scavenging assay, BEPIF exhibited significant free radical scavenging activity.

Conclusions:

It can be concluded that the butanolic extract of P. incarnata flowers has significant antiparkinsonian and cognition enhancing activity which may be associated with its antioxidant potential. Thus, P. incarnata flowers may be employed in treatment of dementia and parkinsonism.

Reversal of reserpine-induced orofacial dyskinesia and catalepsy by Nardostachys jatamansi

Context:

Reserpine-induced orofacial dyskinesia is an animal model of tardive dyskinesia which may be associated with neurodegeneration and free radical damage.

Aim:

The aim was to assess the neuroprotective potential and in vivo antioxidant status of alcoholic extract of roots and rhizomes of Nardostachys jatamansi (ANJ) and its triterpenes (TNJ) in reserpine-induced orofacial dyskinesia.

Materials and Methods:

In the present study, repeated treatment with reserpine (1.0 mg/kg) on each other day for a period of 5 days (days 1, 3, and 5) significantly induced vacuous chewing movements (VCMs) and tongue protrusions (TPs) in rats. The effect on reserpine-induced catalepsy was also studied. The effect of ANJ and TNJ on levels of superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GSH) and inhibition of lipid peroxidation (LPO) in the forebrain region was assessed.

Statistical Analysis:

All observations were expressed as mean ± SEM. Statistical analysis was performed by the one-way ANOVA followed by Dunnett's test. P<0.05 was regarded as statistically significant.

Results:

At the end of the treatment schedule, ANJ and TNJ significantly inhibited reserpine-induced VCM, TP, and catalepsy, and significantly increased the locomotion and rearing in the open-field test. Treatment with ANJ and TNJ exhibited significant elevation in the levels of superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GSH) and inhibition of lipid peroxidation (LPO) in forebrain region compared to the reserpine treated group.

Conclusions:

The study concludes that ANJ and TNJ significantly protected animals against reserpine-induced orofacial dyskinesia as well as catalepsy suggesting its potential value in the treatment of neuroleptic-induced orofacial dyskinesia and Parkinson's disease.

Protective effect of Rubia cordifolia on reserpine-induced orofacial dyskinesia

In this study, the neuroprotective potential and in vivo antioxidant status of extract of roots and rhizomes of Rubia cordifolia L (MERC) in reserpine-induced orofacial dyskinesia was studied. Reserpine (1 mg/kg, s.c.) on day 1, 3 and 5 was used to induce orofacial dyskinesia. At the end of treatment schedule, MERC significantly inhibited reserpine-induced vacuous chewing movements, tongue protrusions, orofacial bursts, catalepsy. MERC significantly increased locomotion and rearing in open field test. MERC exhibited significant elevation in the levels of superoxide dismutase, catalase, glutathione reductase and inhibition of lipid peroxidation in forebrain region, compared with the reserpine treated group. It significantly elevated dopamine levels in the forebrain region. GCMS revealed the presence of anthraquinones, having strong antioxidant activity. It is concluded that oxidative stress might play an important role in reserpine-induced abnormal oral movements and MERC significantly protected animals against reserpine-induced orofacial dyskinesia and has great potential in treatment of neuroleptic induced orofacial dyskinesia.

Antihyperglycemic, antistress and nootropic activity of roots of Rubia cordifolia Linn

Effect of alcoholic extract of roots of Rubia cordifolia was studied on elevated blood glucose level in alloxan treated animals. The extract reduced the blood sugar level raised by alloxan. Effect of alcoholic extract was also investigated on cold restraint induced stress and on scopolamine-induced memory impairment. Alcoholic extract enhanced brain gamma-amino-n-butyric acid (GABA) levels and decreased brain dopamine and plasma corticosterone levels. Acidity and ulcers caused due to cold restraint stress were inhibited by alcoholic extract. Animals treated with alcoholic extract spent more time in open arm in elevated plus maze model. It also antagonized scopolamine induced learning and memory impairment. Baclofen induced catatonia was potentiated by alcoholic extract.

Effect of leaves of Butea frondosa on stress, anxiety, and cognition in rats

The plant Butea frondosa has been indicated in the Indian system of medicine as a plant augmenting memory and as a rejuvenator. The effect of oral administration of the aqueous and alcoholic extracts of the leaves was assessed on stress, cognitive function, and anxiety in albino rats. The antistress activity was evaluated using cold restraint induced ulcers and leukocyte count after subcutaneous injection of milk. The aqueous extract provides protection against stress-induced gastric lesions while both the alcoholic as well as the aqueous extract normalizes the white blood cell count. Effect on cognitive function was evaluated using Cook and Weidley's pole apparatus. The results indicate that the aqueous extract and the alcoholic extract when administered at a dose of 300 mg/kg for a period of 7 days augment both the acquisition as well as the retention of memory of learned task. The absence of an increase in the occupancy of the open arm in the elevated plus maze and in the number of head dips in the hole-board paradigms indicates that both the extracts are devoid of anxiolytic activity. Nootropic activity was compared using piracetam (100 mg/kg po) as the standard, while for anxiolytic and antistress activity, diazepam (1.0 mg/kg ip) was employed as the standard drug. It is concluded that the aqueous and alcoholic extract of B. frondosa possesses antistress and weak nootropic activity.

Clitoria ternatea and the CNS

The present investigation was aimed at determining the spectrum of activity of the methanolic extract of Clitoria ternatea (CT) on the CNS. The CT was studied for its effect on cognitive behavior, anxiety, depression, stress and convulsions induced by pentylenetetrazol (PTZ) and maximum electroshock (MES). To explain these effects, the effect of CT was also studied on behavior mediated by dopamine (DA), noradrenaline, serotonin and acetylcholine. The extract decreased time required to occupy the central platform (transfer latency, TL) in the elevated plus maze (EPM) and increased discrimination index in the object recognition test, indicating nootropic activity. The extract was more active in the object recognition test than in the EPM. The extract increased occupancy in the open arm of EPM by 160% and in the lit box of the light/dark exploration test by 157%, indicating its anxiolytic activity. It decreased the duration of immobility in tail suspension test (suggesting its antidepressant activity), reduced stress-induced ulcers and reduced the convulsing action of PTZ and MES. The extract exhibited tendency to reduce the intensity of behavior mediated via serotonin and acetylcholine. The effect on DA- and noradrenaline-mediated behavior was not significant. In conclusion, the extract was found to possess nootropic, anxiolytic, antidepressant, anticonvulsant and antistress activity. Further studies are necessary to isolate the active principle responsible for the activities and to understand its mode of action.

Anxiolytic and antiemetic activity of Zingiber officinale

The benzene fraction (BF) of a petroleum ether extract of dried rhizomes of ginger, which contained anticonvulsant principle(s), was screened for anxiolytic and antiemetic activity. Motor coordination was not affected by BF per se, but diazepam-induced motor incoordination was potentiated. Animals treated with BF showed decreased occupancy in the closed arm of the elevated plus maze suggesting the presence of anxiolytic principles in the BF. BF also blocked lithium sulphate-induced conditioned place aversion indicating antiemetic activity. These findings suggest that the fraction (BF) possesses anticonvulsant, anxiolytic and antiemetic activity.

Nootropic activity of Albizzia lebbeck in mice

The effect of saponin containing n-butanolic fraction (BF) extracted from dried leaves of Albizzia lebbeck on learning and memory was studied in albino mice using passive shock avoidance paradigm and the elevated plus maze. Significant improvement was observed in the retention ability of the normal and amnesic mice as compared to their respective controls. We have also studied the effects of BF on the behavior influenced by serotonin (5-HT), noradrenaline and dopamine. The brain levels of serotonin, gamma-aminobutyric acid (GABA) and dopamine were also estimated to correlate the behavior with neurotransmitter levels. The brain concentrations of GABA and dopamine were decreased, whereas the 5-HT level was increased. The data indicate the involvement of monoamine neurotransmitters in the nootropic action of BF of A. lebbeck.

Anticonvulsive activity of Butea monosperma flowers in laboratory animals

The bioassay-guided fractionation of dried flowers of Butea monosperma (BM) was carried out to isolate the active principle responsible for its anticonvulsant activity. The petroleum ether extract was fractionated by column chromatography using solvents of varying polarity such as n-hexane, n-hexane:ethyl acetate, ethyl acetate, and methanol. The anticonvulsive principle of B. monosperma was found to be a triterpene (TBM) present in the n-hexane:ethyl acetate (1:1) fraction of the petroleum ether extract. TBM exhibited anticonvulsant activity against seizures induced by maximum electroshock (MES) and its PD(50) was found to be 34.2+/-18.1 mg/kg. TBM also inhibited seizures induced by pentylenetetrazol (PTZ), electrical kindling, and the combination of lithium sulfate and pilocarpine nitrate (Li-Pilo). However, TBM was not effective against seizures induced by strychnine and picrotoxin. TBM exhibited depressant effect on the central nervous system. After repeated use for 7 days, the PD(50) (MES) of TBM increased to 51.5+/-12.1 mg/kg. Similarly, after repeated use of TBM, the duration of sleep induced by pentobarbital was not reduced significantly. Further studies are required to investigate its usefulness in the treatment of epilepsy.

Anxiogenic activity of Myristica fragrans seeds

In the present study, the n-hexane extract of Myristica fragrans (MF) seeds, acetone-insoluble part of the n-hexane extract (AIMF) and trimyristin (TM) were assessed for their anxiogenic activity. The MF (10 and 30 mg/kg), AIMF (30, 100, and 300 mg/kg), and TM (10, 30, and 100 mg/kg) administered intraperitoneally exhibited anxiogenic activity in elevated plus-maze (EPM) paradigm. The open-field test and hole-board test were also used to assess anxiogenic activity of AIMF and TM. In the EPM test, MF, AIMF, and TM decreased the time spent by mice in the open arm and the entries in the open arm. Further, the effect of diazepam (1 mg/kg i.p.), serotonin 5-HT3 receptor antagonist, ondansetron (1 mg/kg i.p.), and 5-HT1A receptor agonist, buspirone (1 mg/kg i.p.), on the occupancy in open arm and entries in open arm was significantly reduced by TM. In the open-field test, AIMF as well as TM reduced the number of rearing and locomotion. Both TM and AIMF reduced the number of head pock in the hole-board test. Inhibition of anxiolytic activity of ondansetron (5-HT3 receptor antagonist), buspirone (5-HT1A receptor agonist), and diazepam [acting on gamma-aminobutyric acid (GABAA) receptor] suggests a nonspecific anxiogenic activity of TM and also a link between 5-HT and GABA systems in the anxiogenic activity of TM.

Nootropic and anxiolytic activity of saponins of Albizzia lebbeck leaves

The effect of saponin containing, n-butanolic fraction (BF), extracted from dried leaves of Albizzia lebbeck, was studied on cognitive behavior and anxiety in albino mice. The elevated plus maze was used for assessment of both nootropic and anxiolytic activity. The nootropic activity was evaluated by recording the effect of BF (0, 10, 25, and 50 mg/kg) on the transfer latency, whereas anxiolytic activity was assessed by studying its effect on the duration of occupancy in the closed arm. Results showed significant improvement in the retention ability of the normal and amnesic mice as compared to their respective controls. Animals treated with BF (25 mg/kg) spent more time in the open arm in a dose-dependent manner. The BF was without any significant effect on motor coordination. However, it significantly inhibited passivity and hypothermia induced by baclofen (10 mg/kg), a GABA(B) agonist. The data emanated in the present study suggests involvement of gamma-aminobutyric acid (GABA) in the nootropic and anxiolytic activity of saponins obtained from A. lebbeck.

Effect of drugs influencing central serotonergic mechanisms on pentazocine-induced catalepsy in mice

Cataleptic effect of pentazocine in mice was affected by pretreatment with dexfenfluramine, fluoxetine, buspirone, p-chlorophenylalanine, cyproheptadine, mianserin, cisapride, ondansetron, pindolol and propranolol. The results suggest that drugs which influence the activity of central serotonergic systems do modulate pentazocine-induced catalepsy in mice.

Baclofen-induced catatonia: modification by serotonergic agents

Baclofen, a GABAB receptor agonist can induce catatonia in rats. This catatonia may serve as a tool for the study of GABAB receptor function. Reciprocal interactions between serotonin (5-HT) and GABAB receptors in the CNS are known to occur. In the present study we examined the effect of various agents that influence serotonergic neurotransmission on baclofen-induced catatonia in rats. The catatonia was rated by means of a scoring method, according to the severity of motor symptoms produced by baclofen (10-15 mg/kg, i.p.). All serotonergic drugs were injected intraperitoneally 30 min prior to baclofen, except the 5-HT synthesis inhibitor p-chlorophenylalanine (PCPA), which was injected 72 and 48 hr prior to baclofen. The 5-HT releaser fenfluramine (10 mg/kg) and the uptake inhibitor fluoxetine (10 mg/kg) reversed, whereas the 5-HT1A agonist buspirone (3 mg/kg) potentiated baclofen-induced catatonia. The 5-HT synthesis inhibitor PCPA (150 x 2 mg/kg), the non-specific 5-HT antagonist cyproheptadine (5 mg/kg), the 5-HT1A/1B antagonist pindolol (3 mg/kg) and the 5-HT2 antagonist sulpiride (20 mg/kg) enhanced baclofen-induced catatonia. It is concluded that the manipulations of central serotonergic mechanisms modulate baclofen-induced catatonia.