Synergistic effect of pinellia total alkaloids and uncaria total alkaloids on anticonvulsant action in mice and rats

Aim To investigate the synergistic effect of the combination of pinellia total alkaloid （PTA） and uncaria total alkaloid （UTA）, and explore the mechanism of anticonvulsant action. Methods Anticonvulsant and toxic effect profiles of combinations of PTA with UTA, alone and at three fixed ratios of 1：4, 1 ：1, 4：1, were evaluated in maximal electroshock （MES）-induced seizures and acute toxicity test in mice. Respective ED50 and LD50 were calculated with Bliss＇s method. Their synergistic effect were evaluated by isobolographic analysis and allowed the determination of benefit indices （BI） for respective combinations. The model of convulsive rats kindled by penicillin topically injected into cortex was used to investigated the content of Glu, Asp, Gly and GABA in hippocampus using high performance liquid chromatography （HPLC）. Results Combinations of PTA and UTA at the ratio of 4：1 were synergistic in MES test and antagonistic in acute toxicity test, showing the best profile for combinations of PTA with UTA. In contrast, the ratios of 1 ：4 and 1 ： 1, despite synergistic in MES test, were additive in acute toxicity test. The 4：1 combination and two drugs alone significantly decreased Glu level and increased GABA level in the hippocampus, but the GABA level in the 4：1 combination group was higher than that in the two drugs alone groups. They did not have significant influence on the levels of ASp and Gly. Conclusion Combinations of PTA and UTA at 4：1 ratio demonstrated synergistic effect in anticonvulsant action and antagonistic effect in toxicity. The anticonvulsant mechanism might be related to decreasing the excitability of Glutamatergic neurons and increasing the inhibition of GABAergic neurons.

Studies on the Synthesis, Anticonvulsant Activity, and the Structure-Activity Relationships of Phenyl Pyridazinones and their GABA Derivatives

In searching for effective anticonvulsant agents,fourteen 6-aryl-4.5-di- hydro-3(2H)pyridazinones.fifteen 6-aryl-3(2H)pyridazinones,and seventeen 3-GABA derivatives of 6-aryIpyridazines have been synthesized,and evaluated in mice for the ability to antagonize maximal electroshock seizure(MES).The ED_(50) values showed that 6-(2′,4′- dichlorophenyt)-3(2H)pyridazinone was the most potent anticonvulsant among these corn- pounds(ED_(50)=10.15 mg/kg).The structure-activity relationships of the aryl pyridazinones were studied.The result showed that:(1)the higher the value of the hydrophobic parameter л of the substituent on the phenyl ring.the more potent the anticonvulsant activity of the corn- pound.and(2)only the compounds with an electron withdrawing substituent on the phenyl ring exhibited appreciable anticonvulsant activity.

A Study of the Relationship Between the Chemical Structure and the Anticonvulsant Activity of the 3-Pyrazolidinones

The Hansch approach was used in the quantitative structure anticonvulsant activity studies of the previously synthesized 1-substituted-and 1.5-disubstituted-3-pyrazo- lidinones.Correlation analysis predicted that 1.5-disubstituted-3-pyrazoljdinones in which 1- substituent is n-propyl but not benzyl.with the total hydrophobic constant of 1-and 5-sub- stituents(∑л)equals to 4.5(optimum value)will have the most potent activity.On the basis of this analysis eleven 5-substituted and I-n-butyl-5-substituted-3-pyrazolidinones were syn- thesized.Pharmacological tests indicated that the prediction of the Hansch analysis of the 3- pyrazolidinones is correct.The Hansch analysis,by including these 11 compounds,gives an almost identical correlation with that previously obtained.

Potent Anticonvulsant 1H-Imidazol-5(4H)-One Derivatives with Low Neurotoxicity

We report here the synthesis and in vivo anticonvulsant/neurotoxicity activities of a series of compounds belonging to 2-aryl-4-arylidene-1-phenyl-1H-imidazol-5(4H)-one. The scaffold is based on the commonality of 5-membered lactam ring structures as successful anticonvulsant agents. The present compounds exhibited a range of anticonvulsant activity in pentylenetetrazole (PTZ)-induced seizure test. In particular, the protection was excellent by compounds bearing furylmethylidene on C4, possibly due to good pharmacokinetic properties. It was found that high lipophilicity and/or electron deficient aryl ring substitution at C4 compromised the anticonvulsant activities. For example, chloro analogues were found much less active than unsubstituted phenyl or furyl derivatives. Regarding side effects, active compounds exerted no observable neurotoxic effect at their therapeutic doses in Chimney test.

A novel series of 2,5-disubstituted 1,3,4-thiadiazoles as potential anticonvulsant agent

In pursuit for better antiepileptic drug and the importance of semicarbazones and 2,5-disubstituted 1,3,4-thiadiazoles as anticonvulsant pharmacophore, a series of novel N-（{5-[（6-methyl-l-benzofuran-3-yl）methyl]-l,3,4-thiadiazol-2-yl}carba- mothioyl）-2/3/4-substitutedbenzamide were designed, synthesized and evaluated for their anticonvulsant activity. The findings of the present studies confirmed that the pharmacophore model with four binding sites is crucial for anticonvulsant activity. Structure-activity relationships among synthesized compounds were also established.

Patch testing and cross sensitivity study of adverse cutaneous drug reactions due to anticonvulsants: A preliminary report

AIM To evaluate the utility of patch test and cross-sensitivity patterns in patients with adverse cutaneous drug reactions(ACDR) from common anticonvulsants. METHODS Twenty-four(M:F = 13:11) patients aged 18-75 years with ACDR from anticonvulsants were patch tested 3-27 mo after complete recovery using carbamazepine, phenytoin, phenobarbitone, lamotrigine, and sodium valproate in 10%, 20% and 30% conc. in pet. after informed consent. Positive reactions persisting on D3 and D4 were considered significant. RESULTS Clinical patterns were exanthematous drug rash with or without systemic involvement(DRESS) in 18(75%), Stevens-Johnsons syndrome/toxic epidermal necrolysis(SJS/TEN) overlap and TEN in 2(8.3%) patients each, SJS and lichenoid drug eruption in 1(4.2%) patient each, respectively. The implicated drugs were phenytoin in 14(58.3%), carbamazepine in 9(37.5%), phenobarbitone in 2(8.3%), and lamotrigine in 1(4.7%) patients,respectively. Twelve(50%) patients elicited positive reactions to implicated drugs; carbamazepine in 6(50%), phenytoin alone in 4(33.3%), phenobarbitone alone in 1(8.3%), and both phenytoin and phenobarbitone in 1(8.33%) patients, respectively. Cross-reactions occurred in 11(92%) patients. Six patients with carbamazepine positive patch test reaction showed cross sensitivity with phenobarbitone, sodium valproate and/or lamotrigine. Three(75%) patients among positive phenytoin patch test reactions had cross reactions with phenobarbitone, lamotrigine, and/or valproate. CONCLUSION Carbamazepine remains the commonest anticonvulsant causing ACDRs and cross-reactions with other anticonvulsants are possible. Drug patch testing appears useful in DRESS for drug imputability and cross-reactions established clinically.

Evaluation of the anticonvulsant and muscle relaxant effects of the methanol root bark extracts of Annona senegalensis

Objective:To investigate the potentials of the root bark of Annona（A.） senegalensis in the control of seizure and related hypnotic and motor incoordination effects in mice using experimental models.Methods:The methanol extract（ME） of the root bark of A.senegalensis was studied in mice using pentylenetetrazole（PTZ） induced convulsions,phenobarbitone induced sleeping time and motor coordination test on rota-rod performance.Acute toxicity and lethality（LD50） lest as well as phytochemical analysis were also carried out.Results:The extract（200,400,800 mg/ kg） exhibited a non- dose dependent significant（P【0.05） delay in the onset of both tonic and clonic phases of seizure induced by PTZ（60 mg/kg,s.c.） as well as offered a 100%protection （200 mg/kg） in mice from PTZ induced seizures.The extract significantly（P【0.05） decreased the latency and increased the duration of phenobarbitone induced sleeping time.At 200 mg/kg, the extract exhibited a significant（P【0.05） motor incoordination.The acute toxicity test revealed an oral LD50 of 1 2%mg/kg,while the phytochemical studies showed the presence of alkaloids, resins,glycosides,carbohydrate,reducing sugar,flavonoids,terpenoids,saponins and tannins. Conclusion:The extract of A senegalensis possessed anticonvulsant activity with pronounced hypnotic and muscle relaxant effects.

Antipyretic and anticonvulsant activity of n-hexane fraction of viola betonicifolia

Objective:To investigate the antipyretic and anticonvulsant activities of n-hexane fraction of Viola betonicifolia(V.betonicifolia).Methods:The antipyretic effect was scrutinized using brewer's yeast induced pyrexia and anticonvlsion effect was tested using pentylenetetrazol and strychnine induced convulsion in mice.Results:N-hexane fraction of V.betonicifolia demonstrated highly significant antipyretic activity during various assessment times(1-5 h)when challenged in yeast induced pyrexia test.The effect was in a dose dependent manner with maximum attenuation(82.50%)observed at 300 mg/kg i.p.When tested in pentylenetetrazol induced convulsion test,the 1st stage(Ear and facial twitching)and 2nd stage(Convulsive wave through the body)was 100%protected during 24 h at all the test doses(300,400 and 500 mg/kg i.p.),while the latency time of remaining stages was significantly increased.The maximum effect was observed by n-hexane fraction of V.betonicifolia at 400 and 500 mg/kg i.p.,as the latency time for generalized clonic-tonic seizure(5th stage)was increased up to 25.34 min.However,n-hexane fraction of V.betonicifolia had no protection in strychnine induced convulsion test.Conclusions:In conclusion,phytopharmacological studies provide scientific foundation to the folk uses of the plant in the treatment of pyrexia and neurological disorders.

Studies on the Relationship Between the Structure and Anticonvulsant Activity of Cinnamamides and Their Analogs

On the basis of systematic modification of the structure of componds of antiepilepsirine type, more than 200 cinnamamides were synthesized and tested by animal assay (maximal electroshock seizure, MES). Pharmacological evaluation showed that the configuration and the substituents on the phenyl ring and the nitrogen of amides, and substituents on the double bond displayed an important effect on the anticonvulsant activity.For studying the effect of the modification of structure to anticonvulsant activity, Hansch approach was employed to study the QSAR among 38 cinnamamides, and Hopfinger' s MSA was employed to study the MSA-QSAR among 26 cinnamamides.

Anticonvulsant effects of medicinal plants with emphasis on mechanisms of action

Epilepsy is a disorder in brain in which clusters of nerve cells, or neurons, occasionally signal abnormally and cause strange emotions, sensations, and behavior, or sometimes muscle spasms, convulsions, and loss of consciousness. Neurotransmitters in central nervous system greatly affect and play a very important part in neuronal excitability.Traditional treatments are still a component of health care system in many communities despite the fact that well-established alternatives are available. In this review article, we addressed epilepsy and its treatments with emphasis on medical plants and introduction of antiepileptic plants and their action mechanisms. Relevant articles published since 2010 were retrieved using the search terms including epileptic seizure, anticonvulsant, medicinal plants, and oxidative stress. Most plants/herbal preparations that are ethnomedically used to treat epilepsy or those which have been tested for anticonvulsant activity were reported. Overall, the results of the published articles show that the symptoms of epilepsy seizure can be inhibited or treated by active ingredients derived from medicinal plants.

Synthesis and evaluation of 4-substituted semicarbazones of levulinic acid for anticonvulsant activity

Objective: A series of 4-aryl substituted semicarbazones of levulinic acid (4-oxo pentanoic acid) was designed and synthesized to meet the structural requirements essential for anticonvulsant activity. Methods: All the compounds were evaluated for anticonvulsant activity. Anticonvulsant activity was determined after intraperitoneal (i.p.) administration to mice by maximal electroshock (MES) and subcutaneous metrazol (ScMet) induced seizure methods and minimal motor impairment was determined by rotorod test. Results: A majority of the compounds exhibited significant anticonvulsant activity after intraperitoneal administration. In the present study 4-(4'-fluoro phenyl) levulinic acid semicarbazone emerged as the most active molecule, showing broad spectrum of activity with low neurotoxicity. Unsubstituted levulinic acid semicarbazone was found to be inactive in all the screens. Conclusion: The results obtained validate the hypothesis that presence of an aryl group near the semicarbazone moiety is essential for anticonvulsant activity. The results also indicate that the hydrophilic-hydrophobic site can accommodate hydrophilic groups.

Synthesis and anticonvulsant activity of some potent 5,6-bis aryl 1,2,4-triazines

In the present research, a series of 5,6-bis aryl 1,2,4-triazines 5a^5f were synthesized by condensation of various benzils 4a^4f with aminoguanidine bicarbonate and were screened in vivo, for their anticonvulsant and neurotoxicity studies. Compounds 5a, 5b and 5d were found to be potent molecules of this series, when compared with the reference drugs phenytoin sodium, diazepam and lamotrigine. The structures of these compounds were established by IR, 1H NMR, 13C NMR and mass spectroscopic data.

Microwave-assisted synthesis,anticonvulsant activity and quantum mechanical modelling of N-(4-bromo-3-methylphenyl) semicarbazones

Objective: To study the effect of halo substitution on disubstituted aryl semicarbazones on the anticonvulsant potential and model the activity based on quantum mechanics. Methods: A series of twenty-six compounds of N4-(4-bromo-3-methylphenyl) semicarbazones were synthesized and evaluated for the anticonvulsant activity in the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ) seizure threshold tests. Some potential compounds were also tested in the subcutaneous strychnine (scSTY) and subcutaneous picrotoxin (scPIC) seizure threshold tests. The synthesized compounds were tested for behavioral impairment and CNS (central nervous system) depression in mice. Quantum mechanical modelling was carried out on these compounds to gain understanding on the structural features essential for activity. Results: Some compounds possessed broad spectrum anticonvulsant activity as indicated by their effect in pentylenetetrazole, strychnine, picrotoxin and maximal electro- shock seizures models in resemblance to other aryl semicarbazone derivatives reported earlier. The higher the difference in HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy levels was, the greater was the activity profile. Conclusion: The pharmacophoric requirements for compounds to exhibit anticonvulsant activity that includes one aryl unit in proximity to a hydrogen donor-acceptor domain and an electron donor have been justified with the molecular orbital surface analysis of the synthesized compounds.

Synthesis and Anticonvulsant Activity of γ-Aminobutyric Acid Derivatives

Under physiological conditions, γ-aminobutyric acid poorly crosses the blood-brain barrier. It is likely that a non-toxic derivative of γ-aminobutyric acid which enters the brain easily will have useful anticonvulsant activity. 16 derivatives of γ-aminobutyric acid with an imine link to a lipophilic carrier were prepared and tested for anticonvulsant activity; six compounds show anticonvulsant activity.

Anticonvulsant, Sedative and Antidepressant Effects of Aqueous Extract of Costus afer Stems in Mice

Epilepsy is a disorder in the nervous system which often causes a loss of consciousness. Traditional treatments are quiet a component of health care system in various populations in spite of the fact that well-established options are available. Most plants are used to treat epilepsy or those which have been verified for anticonvulsant activity were reported. Then, Costus afer is a plant of the Congolese flora used in traditional medicine for its many virtues. Therefore, the anticonvulsant activity of Costus afer was assessed with the strychnine convulsion induction test. Two tests were used for sedative activity such as the barbiturate sleep induction test and motor activity and finally the forced swimming test was also used to assess antidepressant activity. The results showed that the aqueous extract of Costus afer stems had no effects on strychnine-induced seizures at doses of 250 mg/kg and 500 mg/kg compared to the control group. However, the extract of Costus afer stems caused a very significant decrease in motricity at a dose of 500 mg/kg, showing a decrease in the onset time and a very significant increase in sleep duration like the reference molecule such as Diazepam. The aqueous extract of Costus afer stems also caused a decrease in immobility time in mice at a dose of 500 mg/kg.

Molecular Docking Studies on Anticonvulsant Enaminones Inhibiting Voltage-Gated Sodium Channels

Epilepsy is described as the most common chronic brain disorder. A typical symptom of epilepsy results in uncontrolled convulsions caused by temporary excessive neuronal discharges. Although several new anticon-vulsants have been introduced, some types of seizures have still not been adequately controlled with these new and current therapies. There is an urgent need to develop new anticonvulsant drugs to control the many different types of seizures. Many studies have shown that the epilepsies involve more than one mechanism and therefore may be responsible for the various types of observed seizures. Recently reported studies have shown that a group of newly synthesized 6 Hz active anticonvulsant fluorinated N-benzamide enaminones exhibited selective inhibitions of voltage-gated sodium (Nav) channels. Nav channels are responsible for the initial inward currents during the depolarization phases of the action potential in excitable cells. The activation and opening of Nav channels result in the initial phases of action potentials. We hypothesize that there is an essential pharmacophore model for the interactions between these enaminones and the active sites of Nav channels. The research reported here is focused on molecular docking studies of the interactions that occur between the fluorinated N-benzamide enaminones and the Nav channels. These studies may open an avenue for designing anticonvulsant drugs by inhibiting Nav channels.

Synthesis and Evaluation of Anticonvulsant Activity of 6,8-Dimethoxy-3-methyl-1,2,3,4-tetrahydroisoquinoline in PTZ-Induced Seizure Model in Mice

This study we describe the synthesis of a novel structure of anticonvulsant agent as 6,8-dimethoxy-3-methyl-1,2,3,4- tetrahydroisoquinoline by using GYKI52466, which was the potent anticonvulsant agent, as the lead molecule. Com-pound IV was synthesized and anticonvulsant effects was evaluated against Pentylenetetrazole (PTZ)-induced seizure model in mice. The acute anticonvulsant effect was tested with a single dose of 25 and 75 μmol/kg of the synthesis compound. Sodium valproate and normal saline were used as the reference standard and control, respectively. All compounds were injected intraperitoneally to each mouse an hour prior to seizure induced by injection of 60 mg/kg PTZ and observed their behavior for 30 minutes. The result showed that the IV at 75 μmol/kg could delay the latency to first twitch and decrease percent mortality compared to control group.

Evaluation of the Anticonvulsant Activity of the Leaf Methanol Extract of Crassula arborescens （Mill.） Willd. （Crassulaceae） in Mice

Crassula arborescens （Mill.） Willd. subsp. Arborescens is widely used for the treatment of various ailments including diarrhoea, corns, epilepsy and as a purgative. However, no information exists in any literature to verify the acclaimed effectiveness of C. arborescens in the treatment of the various ailments. The study, therefore, intended to investigate the anticonvulsant activity of the leaf methanol extract of C. arborescens in mice. Acute toxicity study and phytochemical qualitative analysis of the plant extracts were also carried out. Chemically-induced convulsion methods were used to assess the anticonvulsant activity of C. arborescens. Standard methods were used for the acute toxicity study and phytochemical analysis of the chemical components of the plant extract. PTZ （pentylenetetrazole）, bicuculline, picrotoxin, NMDLA （N-methyl-DL-aspartic acid） or strychnine produced tonic convulsions in all the mice used. Leaf methanol extract of Crassula arborescens, muscimol, phenobarbitone or diazepam significantly antagonised PTZ, bicuculline or picrotoxin-induced convulsion. C. arborescens or LY233053 significantly antagonised NMDLA-induced tonic convulsion. C. arborescens or phenobarbitone significantly antagonised strychnine-elicited tonic convulsion. Phenytoin or DMSO （dimethylsulfoxide） did not significantly affect the tonic convulsion produced by PTZ, bicuculline, picrotoxin, NMDLA or strychnine. The LDso value obtained from intraperitoneal administration of C. arborescens was 781.6 mg/kg while that following oral administration of the plant extract was over 4,000 mg/kg. The phytochemical qualitative analysis done showed the presence of flavonoids, tannins, reducing sugar, saponins and triterpene steroids. The data obtained in the study show that the leaf methanol extract of Crassula arborescens has anticonvulsant activity which may be underpinned by GABAergic, glutaminergic and glycinergic mechanisms. The high LDso value obtained following the oral administration of the plant extract shows that the leaf methanol extract is non-toxic to animals.

Investigation of Some Possible Mechanisms Involved in the Anticonvulsant Activity of Tulbaghia violacea Harv

Even though Tulbaghia violacea has been used to treat and manage epilepsy in South Africa by traditional medicine practitioners, no evidence in any literature has shown any scientific scrutiny of the effectiveness of the plant species in therapy. This study was intended, therefore, to investigate the anticonvulsant effect of the leaf methanol extract of Tulbaghia violacea by studying its effect against tonic convulsion induced by either PTZ （pentylenetetrazole）, bicuculline, picrotoxin, strychnine or NMDLA （N-methyl-DL-aspartic acid） in mice. Qualitative phytochemical analysis, acute toxicity and HPLC studies were also carried out on the plant species. Leaf methanol extract of Tulbaghia violacea, phenobarbitone, diazepam or muscimol significantly antagonised PTZ, bicuculline or picrotoxin-induced convulsion. Combined treatment of sub-effective doses of T. violacea and muscimol significantly antagonised tonic convulsion induced by PTZ. T. violacea or phenobarbitone significantly antagonised strychnine-induced tonic convulsion. T. violacea or LY233053 significantly antagonised NMDLA-elicited tonic convulsion. Phenytoin or DMSO （dimethylsulfoxide） did not significantly affect the tonic convulsion produced by PTZ, bicuculline, picrotoxin, strychnine or NMDLA. The phytochemical qualitative analysis of the plant species showed the presence of alkaloids, saponins, reducing sugars, flavonoids, cardiac glycosides, triterpene steroids, quinones and tannins. The LD50 value obtained following oral administration of the plant extract was over 4000 mg/kg. The data in the present study indicate that the leaf methanol extract of T. violacea has anticonvulsant activity which is probably underpinned by GABAergic, glutaminergic and glycinergic mechanisms.

Carbamazepine Induced Ebstein-Barr Virus Reactivation: A Rare Manifestation of Anticonvulsant Hypersensitivity Syndrome

Carbamazepine (CBZ) is an antiepileptic drug which has multiple mechanisms of action including stabilization of the inactivated stage of the voltage-gated sodium channels, potentiating gamma-amino butyric acid (GABA) receptors as a GABA antagonist, as well as the serotonin releasing affect. It is effective in neuropathic pain syndromes such as post-herpetic neuralgia and trigeminal neuralgia, as well as epilepsy. We presented a 29-year-old female patient with the diagnosis of trigeminal neuralgia (TN) who experienced a reactivation of the latent Ebstein-Barr Virus (EBV) infection in terms of anticonvulsant hypersensitivity syndrome after CBZ use, who gave her approval to publish her data. Since the clinical and serological findings of EBV re-infection resolved after the discontinuation of the drug, this clinical and serological manifestation was attributed to CBZ. Since common side-effects of CBZ are drowsiness, dizziness, headaches, skin reactions, cognitive dysfunctions, we reported an activation of EBV infection due to CBZ consumption as a rare side-effect of the drug.