Pergularia daemia hydro-ethanolic extract protects against pentylenetetrazole kindling-induced seizures, oxidative stress, and neuroinflammation in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Current antiepileptic drugs fail to control approximately 30% of epilepsies. Therefore, there is a need to develop more effective antiepileptic drugs, and medicinal plants provide an attractive source for new compounds. Pergularia daemia (Asclepiadaceae) is used in Cameroon traditional medicine to treat stroke, anemia, inflammation, and epilepsy. Recently, traditional healers claim that an hydro-ethanolic extract of the roots of P. daemia is more effective than an aqueous extract on refractory seizures.

AIM OF THE STUDY

The antiepileptic effect of P. daemia hydro-ethanolic extract was investigated on the pentylenetetrazole kindling model of temporal lobe epilepsy in mice and possible mechanisms of action.

MATERIALS AND METHODS

Mice were divided into 8 groups treated as follows: normal group received distilled water (10 ml/kg, p.o.), control group received distilled water (10 ml/kg, p.o.), ethanol group received ethanol (5%, p.o.), positive control received sodium valproate (300 mg/kg, p.o.), and test groups received P. daemia hydro-ethanolic (HE) extract (1.6, 4, 8 and 16 mg/kg, p.o.). All groups were kindled by 11 injections of pentylenetetrazole (PTZ) (35 mg/kg, i.p.), once every alternate day (48 ± 2 h), until the development of kindling, i.e., the occurrence of stage 5 seizures for two consecutive trials. One week later, i.e., 29^th day, mice were challenged with a single and lower dose of PTZ (25 mg/kg, i.p.) that does not induce seizures in normal mice but causes seizures in mice prone to seizures and behavioral alterations. After completion of the kindling procedure, Morris water maze, passive avoidance, and open field tests were performed. Afterward, animals were euthanized, and hippocampi were removed for the estimation of the levels of GABA-transaminase (GABA-T), L-glutamate decarboxylase (L-GAD), and γ-aminobutyric acid (GABA). Oxidative stress and neuroinflammation markers also were quantified. Finally, histological analysis of the hippocampus was carried out.

RESULTS

PTZ-kindling induced myoclonic jerks and generalized tonic-clonic seizures in control mice. However, the HE extract of P. daemia (4-16 mg/kg), compared to sodium valproate, significantly protected mice against myoclonic jerks and generalized tonic-clonic seizures. Also, the HE extract (1.6-16 mg/kg) significantly increased the seizure score. Furthermore, the HE extract of P. daemia significantly reduced seizure-induced cognitive impairments. PTZ-kindling induced significant alterations in GABA, GABA-T, and L-GAD contents as well as oxidative stress, and neuroinflammation, and the HE extract significantly reversed these effects, suggesting possible mechanisms. All these activities of the HE extract were confirmed by its protective effect against neuronal loss in the hippocampus.

CONCLUSIONS

The HE extract of P. daemia protected mice against kindled seizures and cognitive impairments, and these effects were greater than those of sodium valproate, a widely used antiepileptic drug. These effects may be mediated by neuromodulatory, anti-oxidant, and anti-inflammatory activities, thus suggesting a neuroprotective effect. These findings help to explain the beneficial use of these HE extracts of P.daemia in traditional medicine to treat epilepsy in Cameroon.

Pergularia daemia alters epileptogenesis and attenuates cognitive impairment in kainate-treated mice: Insight into anti-inflammatory mechanisms

BACKGROUND

About 60% of temporal lobe epilepsies are drug resistant. Thus, medicinal plants are sources of new antiepileptic drugs. Pergularia daemia is used in Cameroon to treat pain, fever, arthritis, infections, and temporal lobe epilepsy. However, there are no scientific reports on the anti-inflammatory activity of P. daemia during epileptogenesis.

OBJECTIVE

This study aimed at determining the involvement of the anti-inflammatory activity of P. daemia during epileptogenesis in kainate-treated mice.

METHODS

Status epilepticus was induced in mice with kainate (15 mg/kg; i.p.). Those developing status epilepticus for 2 h were divided and treated once daily, for two weeks, with distilled water (10 ml/kg; p.o.), P. daemia extract (4.9, 12.3, 24.5, and 49 mg/kg; p.o.), and sodium valproate (300 mg/kg; i.p.) or aspirin (20 mg/kg; i.p.). One hour following the last treatment, the susceptibility of mice to seizures was assessed during epileptogenesis with pentylenetetrazole (40 mg/kg; i.p.). Then, mice were subjected to morris water maze, object recognition, and open-field tests. After completion of behavioral analysis, hippocampi and blood were collected for pro-inflammatory markers or histological analysis.

RESULTS

The extract of P. daemia at all doses significantly reduced the latency and duration of seizures and increased seizure score. P. daemia (24.5 and 49 mg/kg) also prevented SE-induced cognitive impairment. Furthermore, the extract (24.5 and 49 mg/kg) markedly decreased tumor necrosis factor-α, interleukins-1β, and -6 levels in hippocampi or serum. Histological analysis revealed that P. daemia attenuated neuronal loss in CA1 and CA3 areas of the hippocampus.

CONCLUSIONS

These findings suggest that anti-inflammatory mechanisms are involved in the antiepileptogenic effect of P. daemia extract. This justifies therefore its use to treat epilepsy and inflammation in Cameroon traditional folk medicine.

Neuroprotective and Antiamnesic Effects of Mitragyna inermis Willd (Rubiaceae) on Scopolamine-Induced Memory Impairment in Mice

Aim. To assess memory improvement and neuroprotective and antioxidant effects of Mitragyna inermis (M. inermis) leaf decoction on the central nervous system. Methodology. Leaf decoction of M. inermis was tested on learning and memory in normal and scopolamine-induced cognitive impairment in mice using memory behavioral tests such as the Morris water maze, object recognition task, and elevated plus maze. Oxidative stress enzymes-catalase, superoxide dismutase, and the thiobarbituric acid reactive substance, a product of lipid peroxidation-were quantified. In each test, mice 18 to 25 g were divided into groups of 5. Results. The extract reversed the effects of scopolamine in mice. The extract significantly increased discrimination index in the object recognition task test and inflexion ratio in the elevated plus maze test. The times spent in target quadrant in MWM increased while the transfer latency decreased in mice treated by M. inermis at the dose of 196.5 mg/kg. The activity levels of superoxide dismutase and catalase were significantly increased, whereas the thiobarbituric acid reactive substance was significantly decreased after 8 consecutive days of treatment with M. inermis at the dose of 393 mg/kg. Conclusion. These results suggest that M. inermis leaf extract possess potential antiamnesic effects.

Antidepressant properties of aqueous macerate from Gladiolus dalenii corms

BACKGROUND

Gladiolus dalenii Van Geel (Iridaceae) has been used for the treatment of depression and psychotic disorders in African traditional medicine. The aim of this study was to assess the effect of the aqueous extract from the corm of Gladiolus dalenii and its possible mechanisms of action.

MATERIALS AND METHODS

We assessed the antidepressant properties of G. dalenii corm aqueous extract in mice, using the open field, forced swimming, and tail suspension tests. Spontaneous locomotor activity of mice given various doses of G. dalenii extract (per os) was determined in the open field, whereas immobility was evaluated in the other two tests.

RESULTS

Extract maximal effect was observed at 15 mg/kg, as mice displayed a marked reduction in immobility time in both the forced swimming test (80%) and the tail suspension test (66%). In further studies aimed at investigating the mechanism of action of G. dalenii extract, the latter significantly antagonized the effect of N-methyl-D-aspartate (NMDA, 75 mg/kg) at both the doses 15 mg/kg (p<0.001) and 150 mg/kg (p=0.004). A significant reduction in immobility time was also observed following treatment with combinations of a sub-effective dose of extract (7.5 mg/kg) with either the NMDA receptor antagonist D-(-)-2-amino-7-phosphonoheptanoic acid (D-AP7, 50 mg/kg, P< 0.001), the serotonin reuptake inhibitor fluoxetine (5 and 10 mg/kg, P< 0.001 and P< 0.001 respectively), and the multi-target antidepressant imipramine (5 and 10 mg/kg, P< 0.001 and P< 0.001 respectively). Moreover, neither G. dalenii extract alone nor its combinations with NMDA ligands imipramine and fluoxetine enhanced mouse spontaneous locomotor activity.

CONCLUSION

Altogether, these results suggest that G. dalenii has antidepressant properties, probably mediated through interactions with NMDA, serotonin and/ or noradrenergic systems, and may justify its use in traditional medicine.

The anticonvulsant and sedative effects of Gladiolus dalenii extracts in mice

Gladiolus dalenii Van Geel is a medicinal plant commonly used in traditional medicine in Africa to treat epilepsy and many other diseases. Two in vivo mouse models (maximal electroshock and pentylenetetrazol-induced convulsions) were used to evaluate the anticonvulsant activities of the plant extracts. Diazepam-induced sleep was used for the evaluation of the sedative properties. The macerated extract of G. dalenii protected 100 and 83.3% of mice against PTZ- and MES-induced seizures, respectively. The aqueous extract of G. dalenii protected 100 and 83.3% of mice against PTZ- and MES-induced seizures, respectively. The lyophilized extract of G. dalenii also protected 100 and 83.3% of mice against PTZ- and MES-induced seizures, respectively. The coadministration of G. dalenii with diazepam resulted in an additive effect, while the coadministration of G. dalenii with flumazenil or FG7142 resulted in antagonistic effects. The macerate of G. dalenii also exerted sedative activity by reducing the latency time to sleep and increasing the total duration of sleep induced by diazepam. The sleeping time increased from 16±3min in the control group to 118±11min at a dose of 150mg/kg of G. dalenii. The effects of G. dalenii suggested the presence of anticonvulsant and sedative activities that might show efficacy against secondarily generalized tonic-clonic seizures and primary generalized seizures and insomnia in humans.

Antipsychotic and sedative effects of the leaf extract of Crassocephalum bauchiense (Hutch.) Milne-Redh (Asteraceae) in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Crassocephalum bauchiense (Hutch.) Milne-Redh (Asteraceae) has been used as a medicine for the treatment of epilepsy, insomnia, dementia and psychotic disorders in Cameroonian traditional medicine.

AIM OF THE STUDY

This study was designed to examine whether the aqueous extract and the alkaloid fraction prepared from the leaves of Crassocephalum bauchiense possess antipsychotic and sedative properties in rodents.

MATERIALS AND METHODS

The rectal temperature of mice was recorded with a probe thermometer at a constant depth. Novelty-induced rearing behavior is used to evaluate a central excitatory locomotor behavior in mice. The antipsychotic effects of the extracts were assessed using the apomorphine animal model of psychosis. The catalepsy test was tested based on the ability of the leaves extracts of Crassocephalum bauchiense to alter the duration of akinesia by placing the naive mice with both forelegs over a horizontal bar. The extracts of Crassocephalum bauchiense effects were evaluated on sodium pentobarbital-induced sleeping time. In addition, gamma-aminobutyric acid concentrations in the brain treated mice were also estimated.

RESULTS

The aqueous extract and the alkaloid fraction from Crassocephalum bauchiense caused dose-dependent inhibition of novelty-induced rearing behavior, decreased the apomorphine-induced stereotypy and fighting, and had significant fall of the body temperature. The aqueous extract prolonged the sodium pentobarbital sleeping time. This prolongation was not reversed by bicuculline, a light-sensitive competitive antagonist of GABA(A) receptors complex. However, the effect of the aqueous extract on sodium pentobarbital-induced sleeping time was blocked by N-methyl-β-carboline-3-carboxamide, a partial inverse agonist of the benzodiazepine site in the GABA(A) receptor complex and flumazenil, a specific antagonist of the benzodiazepine site in the GABAA receptor complex. In biochemical experiments, the concentration of the inhibitory amino acid, gamma-aminobutyric acid, was significantly increased in the brain of animals treated with the aqueous extract of Crassocephalum bauchiense and sodium valproate.

CONCLUSIONS

The results show that the antipsychotic and sedative properties of Crassocephalum bauchiense are possibly mediated via the blockade of dopamine D-2 receptors and GABAergic activation, respectively. However, pharmacological and chemical studies are continuing in order to characterize the mechanism(s) responsible for these neuropharmacological actions and also to identify the active substances present in the extracts of Crassocephalum bauchiense.

Antipyretic and antinociceptive effects of Nauclea latifolia root decoction and possible mechanisms of action

CONTEXT

 Nauclea latifolia Smith (Rubiaceae) is a small tree found in tropical areas in Africa. It is used in traditional medicine to treat malaria, epilepsy, anxiety, pain, fever, etc.

OBJECTIVE

 The aim of this study was to investigate the effects of Nauclea latifolia roots decoction on the peripheral and central nervous systems and its possible mechanisms of action.

MATERIALS AND METHODS

 The analgesic investigation was carried out against acetic acid-induced writhing, formalin-induced pain, hot-plate and tail immersion tests. The antipyretic activity was studied in Brewer's yeast-induced pyrexia in mice. Rota-rod test and bicuculline-induced hyperactivity were used for the assessment of locomotor activity.

RESULTS

 Nauclea latifolia induced hypothermia and had antipyretic effects in mice. The plant decoction produced significant antinociceptive activity in all analgesia animal models used. The antinociceptive effect exhibited by the decoction in the formalin test was reversed by the systemic administration of naloxone, N(ω)-L-nitro-arginine methyl ester or glibenclamide. In contrast, theophylline did not reverse this effect. Nauclea latifolia (antinociceptive doses) did not exhibit a significant effect on motor coordination of the mice in Rota-rod performance. Nauclea latifolia protected mice against bicuculline-induced behavioral excitation.

DISCUSSION AND CONCLUSION

 Overall, these results demonstrate that the central and peripheral effects of Nauclea latifolia root decoction might partially or wholly be due to the stimulation of peripheric opioid receptors through the action of the nitric oxide/cyclic monophosphate guanosin/triphosphate adenosine (NO/cGMP/ATP)-sensitive- K(+) channel pathway and/or facilitation of the GABAergic transmission.

Anticonvulsant, anxiolytic, and sedative properties of the roots of Nauclea latifolia Smith in mice

Root bark of Nauclea latifolia Smith (Rubiaceae) was evaluated for its anticonvulsant, anxiolytic, and sedative activity in mice. Animal models (maximal electroshock-, pentylenetetrazol-, and strychnine-induced convulsions; N-methyl-D-aspartate-induced turning behavior; elevated plus maze; stress-induced hyperthermia; open field; and diazepam-induced sleep) were used. The decoction from the bark of the roots of N. latifolia strongly increased the total sleep time induced by diazepam. It also protected mice against maximal electroshock-, pentylenetetrazol-, and strychnine-induced seizures. In addition, turning behavior induced by N-methyl-D-aspartate was inhibited. N. latifolia antagonized, in a dose-dependent manner, stress-induced hyperthermia and reduced body temperature. In the elevated plus maze, N. latifolia increased the number of entries into, percentage of entries into, and percentage of time in open arms, and reduced rearing, head dipping, and percentage of time in closed arms. In the open field test, N. latifolia increased crossing and reduced rearing and defecation. It could be concluded that the decoction of N. latifolia, used in traditional medicine in Cameroon in the treatment of fever, malaria, insomnia, anxiety and epilepsy seemed to possess, sedative, anticonvulsant, anxiolytic and antipyretic properties in mice.