Anticonvulsant activity of Tetrahydrolinalool: behavioral, electrophysiological, and molecular docking approaches.

Tetrahydrolinalool (THL) is an acyclic monoterpene alcohol, produced during linalol metabolism and also a constituent of essential oils. As described in the literature, many monoterpenes present anticonvulsant properties, and thus we became interested in evaluating the anticonvulsant activity of Tetrahydrolinalool using in mice model as well as in silico approaches. Our results demonstrated that THL increased latency to seizure onset and also reduced the mortality, in picrotoxin induced seizure tests. The results may be related to GABAergic regulation, which was also suggested in seizure testing induced by 3-mercapto-propionic acid. In the strychnine-induced seizure testing, none of the groups pretreated with THL modulated the parameters indicative of anticonvulsant effect. The electrophysiological results revealed that THL treatment reduces seizures induced by pentylenetetrazole. The in silico molecular docking studies showed that the interaction between THL and a GABAA receptor model formed a stable complex, in comparison to the crystaligraphic structure of diazepam, a structurally related ligand. In conclusion, all the evidences showed that THL presents effective anticonvulsant activity related to the GABAergic pathway, being a candidate for treatment of epileptic syndromes.

Synthesis of novel thiazolidinic-phthalimide derivatives evaluated as new multi-target antiepileptic agents.

Epilepsy is a disease that affects millions of people around the globe and has a multifactorial cause. Inflammation is a process that can be involved in the development of seizures. Thus, the present study proposed the design and synthesis of new candidates for antiepileptic drugs that would also control the inflammatory process. Nine new derivatives of the substituted thiazophthalimide hybrid core were obtained with satisfactory purity ≥99% and yields between 27% and 87%. All compounds showed cell viability values greater than 90% in the culture of PBMC cells from healthy volunteers and, therefore, were not considered cytotoxic. These compounds modulated proinflammatory cytokines IFN-y and IL-17A and can mitigate inflammation. Acute toxicity studies of compound 7i in an animal model indicated that the compound has low toxicity and an LD50 greater than 2 g/kg in healthy adult rats. The same compound did not show positive results for anticonvulsant activity through the PTZ test. However, 7i demonstrates the interaction with the target GABA-A receptor in silico, indicating a possible activity as an agonist of that receptor. Thus, further studies are needed to investigate the anticonvulsant activity, in particular, using models in which the inflammatory process triggers epileptic seizures.

Investigation on the Anticonvulsant Potential of Luteolin and Micronized Luteolin in Adult Zebrafish (Danio rerio).

Epilepsy affects around 50 million people worldwide, and an important number of patients (30%) fail to respond to any available antiepileptic drug. Previous studies have shown that luteolin presents a promising potential as an anticonvulsant. On the other hand, different studies showed that luteolin does not promote anticonvulsant effects. Therefore, there is a lack of consensus about the use of luteolin for seizure control. Luteolin low bioavailability could be a limiting factor to obtain better results. Attractively, micronization technology has been applied to improve flavonoids bioavailability. Thus, the present study aimed to investigate the effects of luteolin on its raw form and micronized luteolin in a PTZ-induced seizure model in adult zebrafish (Danio rerio). Our results demonstrate that luteolin and micronized luteolin did not block PTZ-induced seizures in adult zebrafish. Also, luteolin and micronized luteolin did not provoke behavioral changes. Finally, our results show that 24 h after seizure occurrence, no changes were detected for p70S6Kb, interleukin 1ß, and caspase-3 transcript levels. Altogether, we failed to observe an anticonvulsant potential of luteolin in adult zebrafish, even in its micronized form. However, we recommend new studies to investigate luteolin benefits in epilepsy.

Design, synthesis and biological evaluation of N-substituted α-hydroxyimides and 1,2,3-oxathiazolidine-4-one-2,2-dioxides with anticonvulsant activity.

In this investigation, we studied a family of compounds with an oxathiazolidine-4-one-2,2-dioxide skeleton and their amide synthetic precursors as new anticonvulsant drugs. The cyclic structures were synthesized using a three-step protocol that include solvent-free reactions and microwave-assisted heating. The compounds were tested in vivo through maximal electroshock seizure test in mice. All the structures showed activity at the lower doses tested (30 mg/Kg) and no signs of neurotoxicity were detected. Compound encoded as 1g displayed strong anticonvulsant effects in comparison with known anticonvulsants (ED50 = 29 mg/Kg). First approximations about the mechanisms of action of the cyclic structures were proposed by docking simulations and in vitro assays against sodium channels (patch clamp methods).

Continuous-flow protocol for the synthesis of enantiomerically pure intermediates of anti epilepsy and anti tuberculosis active pharmaceutical ingredients.

Continuous-flow production of chiral intermediates plays an important role in the development of building blocks for Active Pharmaceutical Ingredients (APIs), being α-amino acids and their derivatives widely applied as building blocks. In this work we developed two different strategies for the synthesis of intermediates used on the synthesis of levetiracetam/brivaracetam and ethambutol. The results obtained show that methionine methyl ester can be continuously converted to the desired ethambutol intermediate by RANEY® Nickel dessulfurization/reduction strategy whereas levetiracetam/brivaracetam intermediates could be synthesized by both RANEY® Nickel (without H2) and Pd/C-H2 approach or by photochemical desulfurization.

Neuropharmacological Screening of Chiral and Non-chiral Phthalimide- Containing Compounds in Mice: in vivo and in silico Experiments.

BACKGROUND: Thalidomide, the first synthesized phthalimide, has demonstrated sedative- hypnotic and antiepileptic effects on the central nervous system. N-substituted phthalimides have an interesting chemical structure that confers important biological properties. OBJECTIVE: Non-chiral (ortho and para bis-isoindoline-1,3-dione, phthaloylglycine) and chiral phthalimides (N-substituted with aspartate or glutamate) were synthesized and the sedative, anxiolytic and anticonvulsant effects were tested. METHOD: Homology modeling and molecular docking were employed to predict recognition of the analogues by hNMDA and mGlu receptors. The neuropharmacological activity was tested with the open field test and elevated plus maze (EPM). The compounds were tested in mouse models of acute convulsions induced either by pentylenetetrazol (PTZ; 90 mg/kg) or 4-aminopyridine (4-AP; 10 mg/kg). RESULTS: The ortho and para non-chiral compounds at 562.3 and 316 mg/kg, respectively, decreased locomotor activity. Contrarily, the chiral compounds produced excitatory effects. Increased locomotor activity was found with S-TGLU and R-TGLU at 100, 316 and 562.3 mg/kg, and S-TASP at 316 and 562.3 mg/kg. These molecules showed no activity in the EPM test or PTZ model. In the 4-AP model, however, S-TGLU (237.1, 316 and 421.7 mg/kg) as well as S-TASP and R-TASP (316 mg/kg) lowered the convulsive and death rate. CONCLUSION: The chiral compounds exhibited a non-competitive NMDAR antagonist profile and the non-chiral molecules possessed selective sedative properties. The NMDAR exhibited stereoselectivity for S-TGLU while it is not a preference for the aspartic derivatives. The results appear to be supported by the in silico studies, which evidenced a high affinity of phthalimides for the hNMDAR and mGluR type 1.

Novel sulfamides and sulfamates derived from amino esters: Synthetic studies and anticonvulsant activity.

We report herein the design and optimization of a novel series of sulfamides and sulfamates derived from amino esters with anticonvulsant properties. The structures were designed based on the pharmacophoric pattern previously proposed, with the aim of improving the anticonvulsant action. The compounds were obtained by a new synthetic procedure with microwave assisted heating and the use of adsorbents in the isolation process. All the derivatives showed protection against the maximal electroshock seizure test (MES test) in mice at the lowest dose tested (30 mg/kg) but they did not show significant protection against the chemical induced convulsion by pentylenetetrazole. These results verify the ability of the computational model for designing new anticonvulsants structures with anti-MES activity. Additionally, we evaluated the capacity of the synthesized structures to bind to the benzodiazepine binding site (BDZ-bs) of the γ-aminobutiric acid receptor (GABAA receptor). Some of them showed medium to low affinity for the BDZ-bs.

Sulfamide derivatives with selective carbonic anhydrase VII inhibitory action.

A set of N,N'-disubstituted sulfamides and sodium cyclamate have been tested for their inhibitory action against six isoforms of carbonic anhydrase (CA, EC 4.2.1.1) found in the brain, that is, CA I, CA II, CA VII, CA IX, CA XII and CA XIV, some of which are involved in epileptogenesis. The biological data showed interesting results for CA VII inhibition, the isozyme thought to be a novel antiepileptic target. Strong CA VII inhibitors, with Ki values in the low nanomolar-subnanomolar range were identified. Some of these derivatives showed selectivity for inhibition of CA VII versus the ubiquitous isoform CA II, for which the Ki values were in the micromolar range. Molecular modeling approaches were employed to understand the binding interactions between these compounds and the two CA isoforms, since the mechanism of action of such disubstituted sulfamides was not yet investigated by means of X-ray crystallography.

Synthesis and anticonvulsant activity of bioisosteres of trimethadione, N-derivative-1,2,3-oxathiazolidine-4-one-2,2-dioxides from α-hydroxyamides.

The synthesis and anticonvulsant activity of novel heterocycles N-derivative-1,2,3-oxathiazolidine-4-one-2,2-dioxides, bioisosteres of trimethadione (TMD, oxazolidine-2,4-dione) and phenytoin (PHE), are described. TMD is an anticonvulsant drug widely used against absences seizures in the early 80's and PHE is an antiepileptic drug with a wide spectrum activity. The intermediates of synthesis of N-derivative-1,2,3-oxathiazolidine-4-one-2,2-dioxides, α-hydroxyamides, were obtained using microwave assisted synthesis. Anticonvulsant screening was performed in mice after intraperitoneal administration in the maximal electroshock seizure test (MES) and subcutaneous pentylenetetrazole seizures test (scPTZ). These new compounds showed a wide spectrum activity and were no neurotoxic in the RotoRod test. α-Hydroxyamides and N-derivative-1,2,3-oxathiazolidine-4-one-2,2-dioxides were 3-4700 times more potent than valproic acid in the MES test. Quantification of anticonvulsant protection was calculated (ED(50)) for the most active candidates; α-hydroxyamides 3a-c and 3e, and N-derivative-oxathiazolidine-4-one-2,2-dioxides 5a-c with ED(50) values of 9.1, 53.9, 44.6, 25.2, 15.1, 91.1 and 0.06mg/kg, respectively, in the MES test.

Synthesis and anticonvulsant activity of amino acid-derived sulfamides.

Sulfamides are promising functions for the design of new antiepileptic drugs ( Bioorg. Med. Chem. 2007, 15, 1556-1567; 5604-5614 ). Following previous research in this line, a set of amino acid-derived sulfamides has been designed, synthesized, and tested as new anticonvulsant compounds. The experimental data confirmed the ability of some of the structures to suppress the convulsions originated by the electrical seizure (MES test) at low doses (100 mg/kg).

Design, synthesis, and anticonvulsant activity of some sulfamides.

As part of our search for potential anticonvulsant agents, a set of compounds were designed, synthesized, and evaluated against MES and PTZ tests. Bioisosteric functional group information was used to design a new functionality, sulfamides, that complies with the requirements of the pharmacophore previously defined. Some of the molecules showed a promising anticonvulsant profile as selective anti-MES drugs, being active at low concentrations (30mg/kg). The biological data were confirmed in Phase II of the Anticonvulsant Drug Development Program of the National Institute of Health.

3D-QSAR design of novel antiepileptic sulfamides.

A three-dimensional quantitative structure-activity relationship method, the comparative molecular field analysis (CoMFA), was applied to design new anticonvulsant symmetric sulfamides. The training set (27 structures) was comprised by traditional and new-generation anticonvulsant (AC) ligands that exhibit a potent activity in MES test. Physicochemical determinants of binding, such as steric and electrostatic properties, were mapped onto the molecular structures of the set, in order to interpret graphically the CoMFA results in terms of field contribution maps. The 3D-QSAR models demonstrate a good ability to predict the activity of the designed compounds (r(2)=0.967, q(2)=0.756).

[The anticonvulsive effect of 4,4-bis(hydroxymethyl)-2-phenyl-2-oxazoline]. / Efecto anticonvulsionante de la 2-fenil-4,4-bis (hidroximetil)-2-oxazolina.

INTRODUCTION: Certain compounds belonging to the family of the 2-aryl oxazolines have been reported to act on the central nervous system with a number of different effects and applications, which make them useful as depressants, anaesthetics, anticonvulsants, and so on. AIMS: Our aim was to study the possible effect of 4,4-bis(hydroxymethyl)-2-phenyl-2-oxazoline (OX), obtained by chemical synthesis using microwaves, in two experimental models of epilepsy. MATERIALS AND METHODS: Two models were used: one involving (repeated stimulation) electroconvulsive shock in mice and the other consisted in inducing audiogenic seizures in Mongolian gerbils. Recordings were performed of the potentials in the dentate gyrus (DG) generated in response to electrical stimulation of the entorhinal cortex in anaesthetised gerbils, using the stereotactic technique. RESULTS: A 150 mg/kg dose of OX lowered the number of electrical pulses required to induce the tonic seizures triggered by the electroshock, as well as their duration. This same dose blocked the seizures induced by audiogenic stimuli in the gerbils and significantly reduced their severity (degrees of seizures) and occurrence. OX diminished, in a dose-dependent manner, the amplitude of the excitatory post-synaptic potential and that of the population spike, triggered by stimulating the entorhinal cortex in the DG. CONCLUSIONS: OX acts as an antiepileptic agent and its mechanism of action could be related to the inhibiting effect it exerts on the entorhinal cortex-DG synapses in the hippocampus.

Characterization of the anticonvulsant profile of valpromide derivatives.

The antiepileptic activity of nine derivatives of valpromide is discussed. They comply with a pharmacophore model that establishes the essential structural and electronic features responsible for the protection against the MES test. The model results from the comparison of 17 structures, using density functional methodologies combined with an active analog approach. The derivatives of valpromide have been tested for anticonvulsant activity in mice. These compounds displayed a phenytoin-like profile, being active in the MES test and inactive in the PTZ test. 4-(Valproylamido)benzenesulfonamide is the most active compound, with an ED(50) of 53 micromol/kg and no neurotoxicity at doses up to 1000 micromol/kg. The pharmacological behavior of the drugs points to a sodium channel blocking effect as one of the associated mechanisms. This mechanism was tested positive for N-ethylvalpromide through its competition with the binding of [(3)H]batrachotoxin-A-20 alpha-benzoate to the voltage-dependent sodium channels from rat brain synaptosomes.

Synthesis and pharmacological evaluation of some DL-dichlorophenyl alcohol amides anticonvulsants.

The anticonvulsant activity of a homologous series of DL-dichlorophenyl alcohol amides is described. The compounds DL-2-hydroxy-2-(3',4'-dichlorophenyl) butyramide (4, CAS 620950-11-0), DL-3-hydroxy-3-(3',4'-dichlorophenyl) pentanamide (5, CAS 620950-15-4) and DL-4-hydroxy-4-(3',4'-dichlorophenyl) hexanamide (6, CAS 620950-17-6 ) were prepared and tested. Compounds 4, 5 and 6 exhibited a significant activity in seizures induced by pentetrazol. Incorporation of chlorine in the phenyl ring increased their potency. Compound 4 exhibited a slightly lower activity than the reference drug phenobarbital (CAS 50-06-6).

An effective anticonvulsant prepared following a host-guest strategy that uses hydroxypropyl-beta-cyclodextrin and benzaldehyde semicarbazone.

The convulsions of approximately 25% of epileptics are inadequately controlled by currently available medication; therefore the preparation of new antiepileptic drugs is of great interest. Aryl semicarbazones can be considered a new class of compounds presenting anticonvulsant activity. In addition, they can be orally administered and are more active as anticonvulsants than mephenytoin or phenobarbital. However, one disadvantage of these compounds is their low water solubility. As a strategy to circumvent this problem, a 1:1 inclusion compound of benzaldehyde semicarbazone (BS) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was prepared and characterized. The anticonvulsant activities of the free semicarbazone and of the inclusion compound were evaluated in rats using the maximum electroshock and audiogenic seizures screenings. In both tests the minimum dose of compound necessary to produce activity decreases from 100mg/kg for the free semicarbazone to 35 mg/kg for the inclusion compound, indicating a significant increase in the bio-availability of the drug.

Stereoselective anticonvulsant activity of the enantiomers of (+/-)-2-hydroxy-2-phenylbutyramide.

The enantiomers of the anticonvulsant DL-2-hydroxy-2-phenylbutyramide (1) were prepared by resolving the (-)-quinine and (+)-1-phenylethylamine salts of the acids. The optically active acids were then esterified and reacted with ammonia to give (+)-1 and (-)-1. Optical purity of the amides was greater than 99.9% enantiomeric excess by chiral HPLC. Examination of the infrared spectra of the enantiomers and the racemate of 1 in chloroform solution showed identical spectra, but the spectrum of the racemate in a KBr disc was somewhat different from those of the pure enantiomers. Pharmacologically, 1 and its enantiomers have a similar significant anticonvulsant activity at peak drug effect against pentylenetetrazol seizures, but a variation in time between the enantiomers was found with the anticonvulsant activity. In the rotarod ataxia test (-)-1-possessed the lowest neurotoxicity.

A new homologous series of anticonvulsants: phenyl alcohol amides. Synthesis and pharmacological evaluation.

The anticonvulsant activity of a homologous series of phenyl alcohol amides is described. (+-)-2-Hydroxy-2-phenylbutyramide (1), (+-)-3-hydroxy-3-phenylpentanamide (2) and (+-)-4-hydroxy-4-phenylhexanamide (3) were prepared and tested for their anticonvulsant profile and neurotoxicity. 1, 2 and 3 exhibited a broad profile of anticonvulsant activity and a similar significant activity in the seizures provoked by maximal electroshock, pentetrazol, 4-aminopyridine, bicuculline and thiosemicarbazide, but in the strychnine and picrotoxin tests, the protection was variable. The rotarod ataxia test was used to evaluate their neurotoxicity. In this test 2 possesses the lowest neurotoxicity.