Synthesis, Anticonvulsant, and Antinociceptive Activity of New 3-(2-Chlorophenyl)- and 3-(3-Chlorophenyl)-2,5-dioxo-pyrrolidin-1-yl-acetamides

The new series of 3-(2-chlorophenyl)- and 3-(3-chlorophenyl)-pyrrolidine-2,5-dione-acetamide derivatives as potential anticonvulsant and analgesic agents was synthesized. The compounds obtained were evaluated in the following acute models of epilepsy: maximal electroshock (MES), psychomotor (6 Hz, 32 mA), and subcutaneous pentylenetetrazole (scPTZ) seizure tests. The most active substance-3-(2-chlorophenyl)-1-{2-[4-(4-fluorophenyl)piperazin-1-yl]-2-oxoethyl}-pyrrolidine-2,5-dione (6) showed more beneficial ED50 and protective index values than the reference drug—valproic acid (68.30 mg/kg vs. 252.74 mg/kg in the MES test and 28.20 mg/kg vs. 130.64 mg/kg in the 6 Hz (32 mA) test, respectively). Since anticonvulsant drugs are often effective in neuropathic pain management, the antinociceptive activity for two the promising compounds—namely, 6 and 19—was also investigated in the formalin model of tonic pain. Additionally, for the aforementioned compounds, the affinity for the voltage-gated sodium and calcium channels, as well as GABAA and TRPV1 receptors, was determined. As a result, the most probable molecular mechanism of action for the most active compound 6 relies on interaction with neuronal voltage-sensitive sodium (site 2) and L-type calcium channels. Compounds 6 and 19 were also tested for their neurotoxic and hepatotoxic properties and showed no significant cytotoxic effect.

Structural and immunological identification and antiviral infection experiment of the dominant cytotoxic T lymphocyte epitopes of the oncogenic Marek’s disease virus

Marek’s disease (MD) is a serious cancer caused by MDV in chickens, and it is also the first tumor disease that could be controlled by an attenuated vaccine in the world. However, the attenuated vaccine is able to inhibit only the formation of tumors but cannot prevent the infection of oncogenic viruses; instead, it leads to mutations and the emergence of a number of virulent strains. In this paper, the crystal structures of chicken MHC class I (pBF2*1501) molecules bound with 8-mer and 9-mer MDV peptides were solved. The results showed that the conformations of the 8-mer and 9-mer peptides in the antigen-binding groove (ABG) of pBF2*1501 are different; the ABG-8-mer is flat, and the ABG-9-mer has the “featured” M-type epitope morphology. Based on these results, multiple MDV epitopes were confirmed using the tetramer technique, and the immunoprotective effect of dominant epitope was confirmed using the protein adjuvant HSP108-N333 in BF2*1501-expressing chickens. The results showed that the two epitopes have obvious protective effects after a standard immunization program. After challenge, the mortality rate was only 20%, and the protective index (PI) reached 33% in the epitope group. The results verified that a single epitope could induce extremely strong specific antitumor T lymphocyte immunity. The results show that three key factors are crucial to obtain the best antitumor effect: accurate identification of dominant cytotoxic T lymphocyte (CTL) epitopes, efficient protein adjuvant and MHC matching. Meanwhile, the results also provided obvious advantages for the development of multiple epitope vaccines for tumor diseases.ImportanceMarek’s disease (MD) is the first tumor disease that can be controlled by an attenuated vaccine. However, the attenuated vaccine cannot prevent the infection of the oncogenic virus and instead leads to the emergence of a number of mutated virulent strains. First, the mechanism of the chicken BF2*1501 preferentially presents 9-mer peptide was clarified. Based on this result, multiple MDV epitopes were confirmed, and the dominant epitopes were identified. Subsequently, two epitope groups showed obvious protective effects after a standard immunization program, and the protective index (PI) of one of the epitope groups reached over 30%. The results showed that a single epitope could induce strong and efficient antitumor CTL immunity. Overall, three key factors are crucial to obtain the best antitumor effect: accurate identification of dominant epitopes, efficient protein adjuvant and MHC matching. Our results provide an obvious strategy for the development of multiple epitope vaccines in tumor diseases.

Anticonvulsant Effectiveness and Neurotoxicity Profile of 4-butyl-5-[(4-chloro-2-methylphenoxy)methyl]-2,4-dihydro-3H-1,2,4-triazole-3-thione (TPL-16) in Mice

Protective (antiseizure) effects of 4-butyl-5-[(4-chloro-2-methylphenoxy)-methyl]-2,4-dihydro-3H-1,2,4-triazole-3-thione (TPL-16) and acute neurotoxic effects were determined in the tonic-clonic seizure model and rotarod test in mice. The interaction profile of four classic antiepileptic drugs (carbamazepine, phenobarbital, phenytoin and valproate) with TPL-16 was also determined in the tonic-clonic seizure model in mice. The protective effects of TPL-16 from tonic-clonic seizures (as ED50 values) and acute neurotoxic effects of TPL-16 (as TD50 values) were determined in 4 pretreatment times (15, 30, 60 and 120 min after its i.p. administration), in adult male albino Swiss mice. The interaction profile of TPL-16 with carbamazepine, phenobarbital, phenytoin and valproate in the tonic-clonic seizure model was determined with isobolographic analysis. Total concentrations of carbamazepine, phenobarbital, phenytoin and valproate were measured in the mouse brain homogenates. The candidate for novel antiepileptic drug (TPL-16) administered separately 15 min before experiments, has a beneficial profile with protective index (as ratio of TD50 and ED50 values) amounting to 5.58. The combination of TPL-16 with valproate produced synergistic interaction in the tonic-clonic seizure model in mice. The combinations of TPL-16 with carbamazepine, phenobarbital and phenytoin produced additive interaction in terms of protection from tonic-clonic seizures in mice. None of the total brain concentrations of classic AEDs were changed significantly after TPL-16 administration in mice. Synergistic interaction for TPL-16 with valproate and the additive interaction for TPL-16 with carbamazepine, phenobarbital and phenytoin in the tonic-clonic seizures in mice allows for recommending TPL-16 as the promising drug for further experimental and clinical testing.

Antidotal Potency of the Novel, Structurally Different Adsorbents in Rats Acutely Intoxicated with the T-2 Toxin

In this paper, the potential antidote efficacy of commercially available formulations of various feed additives such as Minazel-Plus®, Mycosorb®, and Mycofix® was considered by recording their incidence on general health, body weight, and food and water intake, as well as through histopathology and semiquantitative analysis of gastric alterations in Wistar rats treated with the T-2 toxin in a single-dose regimen of 1.67 mg/kg p.o. (1 LD50) for 4 weeks. As an organic adsorbent, Mycosorb® successfully antagonized acute lethal incidence of the T-2 toxin (protective index (PI) = 2.25; p < 0.05 vs. T-2 toxin), and had adverse effects on body weight gain as well as food and water intake during the research (p < 0.001). However, the protective efficacy of the other two food additives was significantly lower (p < 0.05). Treatment with Mycosorb® significantly reduced the severity of gastric damage, which was not the case when the other two adsorbents were used. Our results suggest that Mycosorb® is a much better adsorbent for preventing the adverse impact of the T-2 toxin as well as its toxic metabolites compared with Minazel-plus® or Mycofix-plus®, and it almost completely suppresses its acute toxic effects and cytotoxic potential on the gastric epithelial, glandular, and vascular endothelial cells.

Synthesis and Evaluation of N-substituted (Z)-5-(Benzo[d][1,3]dioxol-5- ylmethylene)-2-Thioxothiazolidin-4-one Derivatives and 5-Substituted- Thioxothiazolidindione Derivatives as Potent Anticonvulsant Agents

Background: Epilepsy is a serious and common neurological disorder threatening the health of humans. Despite enormous progress in epileptic research, the anti-epileptic drugs present many limitations. These limitations prompted the development of more safer and effective AEDs. Methods: series of N-substituted (Z)-5-(benzo[d][1,3]dioxol-5-ylmethylene)- 2-thioxothiazolidin-4- one derivatives and 5-substituted-thioxothiazolidindione derivatives were designed, synthesized and tested for anticonvulsant activity against maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ). Neurotoxicity was determined by the rotarod test. Results: Among them, the most potent 4e displayed high protection against MES-induced seizures with an ED50 value of 9.7 mg/kg and TD50 value of 263.3 mg/kg, which provided 4e with a high protective index (TD50/ED50) of 27.1 comparable to reference antiepileptic drugs. 4e clearly inhibits the NaV1.1 channel in vitro. The molecular docking study was conducted to exploit the results. Conclusion: Stiripentol is a good lead compound for further structural modification. Compound 4e was synthesized, which displayed remarkable anticonvulsant activities, and the NaV1.1 channel inhibition was involved in the mechanism of action of 4e.

Evaluation of Anticonvulsant Activity and Toxicity Screening of Semicarbazones Derived from Quinazolinone Scaffold

Background: Epilepsy is one of the most prevalent noncommunicable neurological conditions. More than 10 million people in India are afflicted with epilepsy. Treatment available has many detrimental side effects. Up to one-third of epilepsy patients remain resistance to optimum drug treatment. These facts triggered the further scope and search for newer more effective and less toxic anticonvulsants. Methods: Quinazolinone semicarbazone derivatives showing protection in chemoconvulsant induced seizure models (as reported in our previous study) were further screened in MES and scPTZ induced seizure models. Neurotoxicity was determined; quantification of anticonvulsant activity and toxicity was also done. Finally compounds were screened by liver functional test to ascertain the possible hepatotoxicity in the active compounds. Results: Compounds N-1- (menthone) -N- [3-(4-(substituted)-phenyl) -4-oxo- 3,4-dihydroquinazolin- 2-yl] methyl semicarbazone (3A-d-4, 3B-d-4 and 3C-d-4) showed significant protection in both MES and scPTZ induced seizure model with no neurotoxicity at the given dose. In MES test, compounds showed an ED50 close to that of phenytoin and carbamazepine. They also showed Protective Index (PI) higher as compared to phenytoin and carbamazepine. A high safety profile (HD50/ED50 values) was noted and hypnosis, analgesia, and anesthesia were only observed at higher doses. Conclusion: Compounds showed no significant increase or decrease in the concentration of alkaline phosphatase, Serum Glutamate Oxaloacetate Transaminase (SGOT), Serum Glutamate Pyruvate Transaminase (SGPT), albumin and bilirubin.

A comparative study of anticonvulsant effect of phenytoin and lamotrigine in albino mice

Background: The anticonvulsant activity of lamotrigine has been extensively studied and its role is established. Lamotrigine have shown recently to be useful in various epileptic seizures. Since antiepileptic drugs are used for longer duration, so less toxic drugs should be chosen. So, in the present study the Lamotrigine has been chosen to compare the anticonvulsant action, effectiveness, toxicity and lethal dose of the drug used in the study keeping the phenytoin as a standard drug.Methods: The present study has been carried out in the Department of Pharmacology, Darbhanga Medical College, Laheriasarai. Induction of seizure with the help of electro-convulsiometer in albino mice was done followed by the observation of the anti-convulsant activity of lamotrigine in comparison with phenytoin sodium was made. Side effects or toxicity of the drugs used (Acute neurotoxicity) was observed.Results: Lamotrigine caused lower mortality in comparison to phenytoin for the same dose ranges. The anticonvulsant properties of Lamotrigine were compared with phenytoin and the effect has been found to be satisfactory. Lamotrigine protected experimentally induced grand mal seizure and was observed to be ineffective against experimentally induced petit mal seizure. The ED 50 of Lamotrigine was found to be higher and the toxic dose was also higher in comparision with standard drugs. The protective index of lamotrigine was found to be less than that of phenytoin. Margin of safety of the drug was found to be more due to their shorter protective index than that of phenytoin.Conclusions: Lamotrigine can be used clinically as anticonvulsant in Grandmal type of epilepsy but not in Petitmal epilepsy, and has equivocal anticonvulsant effect but slightly less toxicity to phenytoin but further elaborate screening of the drug by various experiments is needed to come to a precise conclusion.