Anxiolytic-like effects of Pseudospondias microcarpa hydroethanolic leaf extract in zebrafish: Possible involvement of GABAergic and serotonergic pathways

Pseudospondias microcarpa is used in ethnomedicine to manage central nervous system diseases. The hydroethanolic extract (PME) from the leaves of the plant has shown anxiolytic-like properties in mice anxiety models. However, its effects in chronic anxiety models and possible mechanism(s) of action were not studied. Therefore, the current study evaluated the anxiolytic-like mechanisms of PME in zebrafish models of anxiety. The zebrafish light dark test (LDT) and novel tank test (NTT) were employed to assess the anxiolytic-like effects of PME (0.1, 0.3, 1.0 mg mL-1), fluoxetine (3 × 10-5 mg mL-1) and diazepam (1.5 × 10-7 mg mL-1). The chronic unpredictable stress (CUS) test was used to further evaluate the extract's anxiolytic-like properties. The potential mechanisms of anxiolytic action of the extract was evaluated after pre-treated with flumazenil, granisetron, methysergide, or pizotifen, all at 1 × 10-3 mg mL-1. The extract significantly decreased anxiety behaviours in the NT and LD tests. These observed effects of the extract were however counteracted by flumazenil, granisetron, methysergide and pizotifen pre-treatment. In addition, PME treatment significantly reversed CUS-induced anxiety behaviours in zebrafish. Results show that PME possesses anxiolytic-like effects possibly through interaction with serotonergic and gamma-aminobutyric acid mediated pathways.

Increased BDNF and hippocampal dendritic spine density are associated with the rapid antidepressant-like effect of iron-citalopram and iron-imipramine combinations in mice

Iron supplementation previously demonstrated antidepressant-like effects in post-partum rats. The present study evaluates the possible synergistic antidepressant effect of sub-therapeutic dose of iron co-administered with citalopram or imipramine in female Institute of Cancer Research mice. Depression-like symptoms were induced in the forced swim (FST), tail suspension (TST), and open space swim (OSST) tests while open field test (OFT) was used to assess locomotor activity. Mice (n=8) received iron (0.8- 7.2 mg/kg), citalopram (3-30 mg/kg), imipramine (3-30 mg/kg), desferrioxamine (50 mg/kg) or saline in the single treatment phase of each model and subsequently a sub-therapeutic dose of iron co-administered with citalopram or imipramine. Assessment of serum BDNF and dendritic spine density was done using ELISA and Golgi staining techniques respectively. Iron, citalopram and imipramine, unlike desferrioxamine, reduced immobility score in the TST, FST and OSST without affecting locomotor activity, suggesting antidepressant-like effect. Sub-therapeutic dose of iron in combination with citalopram or imipramine further enhanced the antidepressant-like effect, producing a more rapid effect when compared to the iron, citalopram or imipramine alone. Iron, citalopram and imipramine or their combinations increased serum BDNF concentration, hippocampal neuronal count and dendritic spine densities. Our study provides experimental evidence that iron has antidepressant-like effect and sub-therapeutic dose of iron combined with citalopram or imipramine produces more rapid antidepressant-like effect. We further show that iron alone or its combination with citalopram or imipramine attenuates the neuronal loss associated with depressive conditions, increases dendritic spines density and BDNF levels. These finding suggest iron-induced neuronal plasticity in the mice brain.

Fast-onset effects of Pseudospondias microcarpa (A. Rich) Engl. (Anacardiaceae) hydroethanolic leaf extract on behavioral alterations induced by chronic mild stress in mice

INTRODUCTION

Pseudospondias microcarpa (Anacardiaceae) is a plant widely used traditionally for treating various central nervous system disorders. A previous study in our laboratory confirmed that the hydroethanolic leaf extract (PME) of the plant produces an antidepressant-like effect in rodent models of behavioral despair. However, its effect on depressive-like behavior induced by chronic mild stress (CMS) and its time course of action are still unknown. In this context, the long-term effects of PME on cognitive function and depressive- and anxiety-like behavior caused by CMS were assessed.

METHODS

Male ICR mice were exposed to CMS for nine weeks and anhedonia was evaluated by monitoring sucrose intake (SIT) weekly. PME (30, 100, or 300 mg kg-1) or fluoxetine (FLX) (3, 10, or 30 mg kg-1) was administered to the mice during the last six weeks of CMS. Behavioral tests-coat state, splash test, forced swimming test (FST), tail suspension test (TST), elevated plus maze (EPM), open field test (OFT), novelty suppressed feeding (NSF), EPM transfer latency, and Morris water maze (MWM)-were performed after the nine-week CMS period.

RESULTS

When the mice were exposed to CMS, their SIT and grooming behavior reduced (splash test), their coat status was poor, they became more immobile (FST and TST), more anxious (OFT, EPM, and NSF), and their cognitive function was compromised (EPM transfer latency and MWM tests). Chronic PME treatment, however, was able to counteract these effects. Additionally, following two (2) weeks of treatment, PME significantly boosted SIT in stressed mice (30 mg kg-1, P<0.05; 100 mg kg-1, P<0.05; and 300 mg kg-1, P<0.001), as compared to four (4) weeks of treatment with FLX.

CONCLUSION

The present findings demonstrate that PME produces a rapid and sustained antidepressant-like action and reverses behavioral changes induced by chronic exposure to mild stressors.

Pharmaceutical and pharmacokinetic evaluation of a newly formulated multiparticulate matrix of levodopa and carbidopa

Levodopa is routinely co-administered with carbidopa in the management of Parkinson's disease. Although the aforementioned combination therapy is effective, there may be fluctuating plasma levels of levodopa after oral administration. We formulated and evaluated the kinetic characteristics of the chitosan-pectin-based multiparticulate matrix of levodopa and carbidopa. Pectin was extracted from the cocoa husk, and the chitosan-pectin-based matrix was prepared by wet granulation. Formulations were evaluated for drug-excipient compatibility, drug content, precompression properties and in vitro release. For pharmacokinetic evaluation, rats were put into groups and administered either chitosan-pectin based matrix of levodopa/carbidopa, Sinemet^® CR or levodopa/carbidopa immediate release powder. Rats were administered the different formulations of levodopa/carbidopa (20/5 mg/kg) per os every 12 hours. The pharmacokinetic parameters of levodopa were estimated for the various treatment groups. The percentage content of levodopa and carbidopa in the various formulations was within the acceptance criteria. The AUC_0-24 for levodopa/carbidopa multiparticulate matrix (Formulation 3: 484.98 ± 18.70 μg.hr/mL); Formulation 4: 535.60 ± 33.04 μg.hr/mL), and C_max (Formulation 3: 36.28 ± 1.52 μg/mL; Formulation 4: 34.80 ± 2.19 μg/mL) were higher than Sinemet^® CR (AUC_0-24 262.84 ± 16.73 μg.hr/mL and C_max 30.62 ± 3.37 μg/mL). The t _1/2 of the new formulation was longer compared to Sinemet^® CR.

Gestational iron supplementation reverses depressive-like behavior in post-partum Sprague Dawley rats: Evidence from behavioral and neurohistological studies

Background

Postpartum depression is a mood disorder that affects about 9–20% of women after child birth. Reports suggest that gestational iron deficiency can cause a deficit in behavioral, cognitive and affective functions and can precipitate depressive symptoms in mothers during the postpartum period. The present study examined the effect of iron supplementation on depressive behavior during postpartum period in a rat model.

Method

Female Sprague-Dawley rats were crossed. Pregnant rats received iron, fluoxetine, desferrioxamine or vehicle throughout the period of gestation. During the postpartum period, mothers from all groups were taken through the open field test (OFT), forced swim test (FST), novelty-induced hypophagia (NIH) and sacrificed for histological examination of the brains.

Results

Results showed that rats treated with iron-chelating agent, desferrioxamine, and vehicle during gestation exhibited increased immobility scores in the FST, increased latency to feed and reduced feeding in the NIH with corresponding decreased number of neurons and dendritic branches in the cortex of the brain. These depression-related effects were attenuated by perinatal iron supplementation which showed decreased immobility scores in the FST comparable to rats treated with fluoxetine, a clinically effective antidepressant. Iron treatment also decreased latency to feeding while increasing feeding behavior in the NIH. Iron-treated dams had a higher number of neurons with dendritic connections in the frontal cortex compared to vehicle- and desferrioxamine-treated groups.

Conclusion

The results suggest that, iron supplementation during gestation exerts an antidepressant-like effect in postpartum Sprague-Dawley rats, attenuates neuronal loss associated with depression and increases dendritic spine density.

•

Iron supplementation during gestation exerts an antidepressant-like effect in postpartum Sprague-Dawley rats.

•

Iron supplementation during gestation attenuates neuronal loss associated with depression.

•

Iron-treated dams had a higher number of neurons with dendritic connections in the frontal cortex.

Glycine/NMDA Receptor Pathway Mediates the Rapid-onset Antidepressant Effect of Alkaloids From Trichilia Monadelpha

INTRODUCTION

Major depressive disorder is often associated with suicidal tendencies, and this condition accentuates the need for rapid-acting antidepressants. We previously reported that Alkaloids (ALK) from Trichilia monadelpha possess antidepressant action in acute animal models of depression and that this effect is mediated through the monoamine and L-arginine-NO-cGMP pathways. This study investigated the possible rapid-onset antidepressant effect of ALK from T. monadelpha and its connection with the glycine/NMDA receptor pathway.

METHODS

The onset of ALK action from T. monadelpha was evaluated using the Open Space Swim Test (OSST), a chronic model of depression. The modified forced swimming and tail suspension tests were used to assess the effect of the ALK on the glycine/NMDA receptor pathway. The Instutute of Cancer Research (ICR) mice were treated with either ALK (30-300 mg/kg, orally [PO]), imipramine (3-30 mg/kg, PO), fluoxetine (3-30 mg/kg, PO), or saline. To identify the role of glycine/NMDA receptor pathway in the effect of ALK, we pretreated mice with a partial agonist of the glycine/NMDA receptor, D-cycloserine (2.5 mg/kg, intraperitoneally [IP]), and an agonist of glycine/NMDA receptor, D-serine (600 mg/kg, IP), before ALK administration.

RESULTS

ALK reversed immobility in mice after the second day of drug treatment in the OSST. In contrast, there was a delay in the effects induced by fluoxetine and imipramine. ALK also increased mean swimming and climbing scores in mice. ALK was more efficacious than imipramine and fluoxetine in reducing immobility and increasing distance traveled. It is noteworthy that ALK was less potent than fluoxetine and imipramine. D-cycloserine potentiated mobility observed in the ALK- and fluoxetine-treated mice. In contrast, D-serine decreased mobility in the ALK-treated mice.

CONCLUSION

The study results suggest that ALK from T. monadelpha exhibits rapid antidepressant action in mice, and the glycine/NMDA receptor pathway possibly mediates the observed effect.

An extract of Synedrella nodiflora (L) Gaertn exhibits antidepressant properties through monoaminergic mechanisms

Synedrella nodiflora (SNE) has been used traditionally for many neurological conditions and some of these neuroactive effects have been scientifically substantiated. The usefulness of SNE in depression has however not been investigated despite the availability of data in other disease models indicating it may be useful. The present study therefore examined the effect of SNE in acute murine models of depression and the possible mechanisms mediating its activities in these models. Preliminary qualitative phytochemical and high performance liquid chromatography (HPLC) screening were conducted on SNE. The behavioural effects of SNE (100, 300 and 1000 mg/kg) pre-treated mice were examined in the forced swimming (FST) and tail suspension (TST) tests. Behavioural events such as mobility (swimming, climbing, curling and climbing), and immobility, were scored. The possible involvement of monoamines in the effects of SNE was assessed in the TST by pre-treating mice with α-methyldopa, reserpine and para-chlorophenylalanine (pCPA) in separate experiments. Flavonoids, tannins, saponins, alkaloids, cardiac glycosides, coumarins, triterpenes, sterols, anthraquinones and phenolic compounds were present in SNE. HPLC analysis revealed the presence of two major constituents observed at retention times 42.56 and 46.51 min, with percentage composition of 45.72% and 36.88% respectively. SNE significantly reduced immobility scores in both FST and TST, suggesting antidepressant effects. The antidepressant properties of SNE were reversed by the pre-treatment of α-methyldopa, reserpine and pCPA, suggesting a possible involvement of monoamines (noradrenaline and serotonin) in its mechanism(s) of actions. SNE exhibits antidepressant effects, possibly mediated through an interplay of enhancement of noradrenergic and serotoninergic mechanisms.

Antidepressant Potentials of Components from Trichilia monadelpha (Thonn.) J.J. de Wilde in Murine Models

Trichilia monadelpha is a common medicinal plant used traditionally in treating central nervous system conditions such as epilepsy, depression, pain, and psychosis. In this study, the antidepressant-like effect of crude extracts of the stem bark of T. monadelpha was investigated using two classical murine models, forced swimming test (FST) and tail suspension test (TST). The extracts, petroleum ether, ethyl acetate, and hydroethanolic extracts (30-300 mg/kg, p.o.), standard drug (imipramine; fluoxetine, 3-30 mg/kg, p.o.), and saline (vehicle) were given to mice one hour prior to the acute study. In a separate experiment the components (flavonoids, saponins, alkaloids, tannins, and terpenoids; 30-300 mg/kg, p.o.) from the most efficacious extract fraction were screened to ascertain which components possessed the antidepressant effect. All the extracts and components significantly induced a decline in immobility in the FST and TST, indicative of an antidepressant-like activity. The extracts and some components showed increase in swimming and climbing in the FST as well as a significant enhancement in swinging and/or curling scores in the TST, suggesting a possible involvement of monoaminergic and/or opioidergic activity. This study reveals the antidepressant-like potential of the stem bark extracts and components of T. monadelpha.

Analgesic effects of a hydro-ethanolic whole plant extract of Synedrella nodiflora (L.) Gaertn in paclitaxel-induced neuropathic pain in rats

Background

Synedrella nodiflora is used by traditional healers in Ghana for the management of epilepsy and pain. The hydro-ethanolic extract of the whole plant has demonstrated antinociceptive effect in various animal models of pain. This study investigated the potential benefit of the hydro-ethanolic extract in a rat model of paclitaxel-induced neuropathic pain.

Methods

Neuropathy was induced in rats by a continuous intraperitoneal administration of paclitaxel (2 mg/kg) for 5 days. Baseline latencies to thermal pain were recorded before the first injection of paclitaxel and during the 5 day induction period. Following the induction, the rats in designated treatment group were treated with the hydro-ethanolic extract (100, 300 and 1000 mg/kg, p.o) or pregabalin (10, 30 and 100 mg/kg) or vehicle (distilled water) and their responses to thermal hyperalgesia measured every 30 for a total period of 3 h.

Results

There was a significant difference between the baseline reaction latency and what was observed on the 5th day of the induction of neuropathy. Two days after the induction of neuropathy, the extract and pregabalin significantly and dose-dependently produced antinociceptive effect during the 3-h test period.

Conclusion

The hydro-ethanolic extract of the whole plant of Synedrella nodiflora possess analgesic effect in paclitaxel-induced neuropathy in rats.

Analgesic properties of aqueous leaf extract of Haematostaphis barteri: involvement of ATP-sensitive potassium channels, adrenergic, opioidergic, muscarinic, adenosinergic and serotoninergic pathways

BACKGROUND

Pain is the most common cause of patients seeking medical advice as a result of its association with different pathologies. This study evaluated the antinociceptive property of Haematostaphis barteri as well as the possible mechanism(s) associated with its antinociceptive property.

METHODS

Mice were administered H. barteri (30-300 mg kg-1; p.o.), followed by intraplantar injection of 10 μL of 5% formalin into the hind paws. The pain score was determined for 1 h in the formalin test. The possible nociceptive pathways involved in the antinociceptive action of H. barteri were determined by pre-treating mice with theophylline (5 mg kg-1, a non-selective adenosine receptor antagonist), naloxone (2 mg kg-1, a non-selective opioid receptor antagonist), glibenclamide (8 mg kg-1; an ATP-sensitive K+ channel inhibitor), and atropine (3 mg kg-1; non-selective muscarinic antagonist).

RESULTS

H. barteri (30-300 mg kg-1) significantly and dose dependently precluded both first and second phases of nociception. Pre-treatment with naloxone had no effect on the analgesic activities of H. barteri in the first phase. Again, pre-treatment with atropine and glibenclamide did not significantly reverse the neurogenic antinociception of the extract in phase 1. However, theophylline reversed the analgesic effect of the extract in the first phase. In phase 2, theophylline had no effect on the analgesic activities of the extract. Naloxone, atropine, and glibenclamide significantly blocked the antinociception of H. barteri in the inflammatory phase of the formalin test.

CONCLUSIONS

H. barteri possesses antinociceptive property mediated via the opioidergic, adrenergic, muscarinic, ATP-sensitive K+ channels, and adenosinergic nociceptive pathways.

Anxiolytic-like effect of the leaves of Pseudospondias microcarpa (A. Rich.) Engl. in mice

BACKGROUND

Pseudospondias microcarpa is a plant used for managing various diseases including CNS disorders. Previous studies showed sedative and anticonvulsant effects, suggesting possible anxiolytic activity. This study therefore assessed the anxiolytic effects of P. microcarpa hydroethanolic leaf extract (PME) in mice.

METHODS

In the present study, anxiolytic-like effect of the extract in behavioural paradigms of anxiety - the elevated plus maze (EPM), light/dark box (LDB), social interaction test and stress-induced hyperthermia (SIH) - was evaluated.

RESULTS

Mice treated with PME (30-300 mg kg-1, p.o.) exhibited anxiolytic-like activity similar to diazepam in all the anxiety models used. The extract increased open arm activity (p<0.05) in the EPM as well as increasing the time spent in the lit area in relation to the time spent in the dark area of the LDB. Sociability and preference for social novelty significantly (p<0.05-0.001) increased in mice treated with PME. In the SIH paradigm in mice, both PME and the benzodiazepine receptor agonist, diazepam, significantly (p<0.05) reduced the stress-induced increase in rectal temperature. The extract did not impair motor coordination and balance in the beam walk test.

CONCLUSIONS

Results of the present study indicate that PME possesses anxiolytic-like effects in mice.

Unsweetened Natural Cocoa Powder Has the Potential to Attenuate High Dose Artemether-Lumefantrine-Induced Hepatotoxicity in Non-Malarious Guinea Pigs

Objective. This study investigated the elemental composition of unsweetened natural cocoa powder (UNCP), its effect on nitric oxide, and its hepatoprotective potential during simultaneous administration with high-dose artemether/lumefantrine (A/L). Method. Macro- and microelements in UNCP were analyzed with EDXRF spectroscopy. Thirty (30) male guinea-pigs were then divided into five groups. For groups 3 (low-dose), 4 (medium-dose), and 5 (high-dose), the animals received oral UNCP prophylactically for 14 days. Group 1 received distilled water (14 days) and group 2 A/L for the last 3 days (days 12 to 14). After euthanisation, biochemical and histopathological examinations were carried out in all groups. Results. Phytochemical analysis of UNCP showed the presence of saponins, flavonoids, tannins, and cardiac glycosides. Thirty-eight (38) macro- and microelements were found. UNCP produced significant decreases in ALT, ALP, GGT, and AST levels. A significant increase in total protein levels was observed during A/L+UNCP administration in comparison to 75 mg/kg A/L group. Histopathological examinations buttressed the protective effects of cocoa administration. UNCP administration increased nitric oxide levels 149.71% (P < 0.05) compared to controls. Conclusion. UNCP increases nitric oxide levels and has hepatoprotective potential during A/L administration. A high level of copper was observed which may be detrimental during high daily consumptions of UNCP.

Enhancement of inhibitory neurotransmission and inhibition of excitatory mechanisms underlie the anticonvulsant effects of Mallotus oppositifolius

CONTEXT

Mallotus oppositifolius is a shrub that is used traditionally to treat epilepsy, but its potential has not been scientifically validated.

AIMS

This study investigated the anticonvulsant properties and possible mechanism of action of the 70% v/v hydroalcoholic extract of the leaves of M. oppositifolius.

MATERIALS AND METHODS

Inprinting control region (ICR) mice (25-30 g) were pretreated with the M. oppositifolius leaf extract (10-100 mg/kg) before administering the respective convulsants (pentylenetetrazole [PTZ], picrotoxin [PTX], strychnine [STR], 4-aminopyridine [4-AP], and pilocarpine). The effect of the extract in maximal electroshock seizure (MES) model was investigated also.

STATISTICAL ANALYSIS

Data were presented as mean ± standard error of the mean and were analyzed with one-way analysis of variance (ANOVA) or two-way ANOVA where appropriate with Newman-Keuls or Bonferroni post hoc test respectively. P < 0.05 was considered significant.

RESULTS

In both PTX and PTZ test, extract delayed the onset of seizures and reduced the frequency and duration of seizures. In the STR-induced seizure test, the extract significantly delayed the onset of seizures and reduced the duration of seizures. The extract also delayed the onset of clonic and tonic seizures as well as increasing the survival of mice in the 4-AP-induced seizure test. It further reduced the duration of tonic limb extensions in the MES test. In the pilocarpine-induced status epilepticus, the extract significantly delayed the onset of clonic convulsions and reduced the frequency and duration of seizures. Moreover, the anticonvulsant effect of the extract was attenuated by flumazenil, a benzodiazepine/gamma-aminobutyric acid (GABA) receptor antagonist.

CONCLUSION

These findings show that the extract has anticonvulsant effect possible mediated by GABAergic, glycinergic neurotransmission, and potassium channel conductions. It may also be acting by antagonizing muscarinic receptor activation and N-Methyl-D-aspartate receptor activation.