Synthesis, anti-inflammatory, analgesic, COX1/2-inhibitory activity, and molecular docking studies of hybrid pyrazole analogues.

This article reports on the design, synthesis, and pharmacological activity of a new series of hybrid pyrazole analogues: 5a-5u. Among the series 5a-5u, the compounds 5u and 5s exhibited potent anti-inflammatory activity of 80.63% and 78.09% and inhibition of 80.87% and 76.56% compared with the standard drug ibuprofen, which showed 81.32% and 79.23% inhibition after 3 and 4 hours, respectively. On the basis of in vivo studies, 12 compounds were selected for assessment of their in vitro inhibitory action against COX1/2 and TNFα. The compounds 5u and 5s showed high COX2-inhibitory activity, with half-maximal inhibitory concentrations of 1.79 and 2.51 µM and selectivity index values of 72.73 and 65.75, respectively, comparable to celecoxib (selectivity index =78.06). These selected compounds were also tested for TNFα, cytotoxicity, and ulcerogenicity. Docking studies were also carried out to determine possible interactions of the potent compounds (5u and 5s), which also showed high docking scores of -12.907 and -12.24 compared to celecoxib, with a -9.924 docking score. These selective COX2 inhibitors were docked into the active site of COX2, and showed the same orientation and binding mode to that of celecoxib (selective COX2 inhibitor). Docking studies also showed that the SO2NH2 of 5u and 5s is inserted deep inside the selective pocket of the COX2-active site and formed a hydrogen-bond interaction with His90, Arg513, Phe518, Ser353, Gln192, and Ile517, which was further validated by superimposed docked pose with celecoxib.

Design and synthesis of new of 3-(benzo[d]isoxazol-3-yl)-1-substituted pyrrolidine-2, 5-dione derivatives as anticonvulsants.

A series of 3-(benzo[d]isoxazol-3-yl)-N-substituted pyrrolidine-2, 5-dione (7a-7d, 8a-8d, 9a-9c) have been prepared and evaluated for their anticonvulsant activities. Preliminary anticonvulsant activity was performed using maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) tests after intraperitoneal (ip) injection into mice, which are the most widely employed models for early identification of anticonvulsant candidate. The acute neurological toxicity (NT) was determined applying rotorod test. The quantitative evaluation after oral administration in rats showed that the most active was 3-(benzo[d]isoxazol-3-yl)-1-(4-fluorophenyl) pyrrolidine-2, 5-dione (8a) with ED50 values of 14.90 mg/kg. Similarly the most potent in scPTZ was 3-(benzo[d]isoxazol-3-yl)-1-cyclohexylpyrrolidine-2, 5-dione (7d) with ED50 values of 42.30 mg/kg. These molecules were more potent and less neurotoxic than phenytoin and ethosuximide which were used as reference antiepileptic drugs.

Design, synthesis and anticonvulsant evaluation of N-(benzo[d]thiazol-2-ylcarbamoyl)-2-methyl-4-oxoquinazoline-3(4H)-carbothioamide derivatives: a hybrid pharmacophore approach.

Novel N-(benzo[d]thiazol-2-ylcarbamoyl)-2-methyl-4-oxoquinazoline-3(4H)-carbothioamide derivatives were synthesized and evaluation of their anticonvulsant effects was done using various models of experimental epilepsy. Initial anticonvulsant activities of the compounds were investigated using intraperitoneal (i.p.) maximal electroshock shock (MES), subcutaneous pentylenetetrazole (scPTZ) seizure models in mice. The quantitative assessment after oral administration in rats showed that the most active was 2-methyl-4-oxo-N-(6-(trifluoromethoxy)benzo[d]thiazol-2-ylcarbamoyl)quinazoline-3(4H)-carbothioamide (SA 24) with ED50 values of 82.5 µmol/kg (MES) and 510.5 µmol/kg (scPTZ). This molecule was more potent than phenytoin and ethosuximide which were used as reference antiepileptic drugs. To explain the possible mechanism for anticonvulsant action, some of the selected active compounds were subjected to GABA (γ-amino butyric acid) assay and AMPA ((S)-2-amino-3-(3-hydroxyl-5-methyl-4-isoxazolyl) propionic acid) induced seizure test.

Synthesis and anticonvulsant activity of some 2-(2-{1-[substituted phenyl]ethylidene}hydrazinyl)-4-(4-methoxy-phenyl)-6-oxo-1,6-dihydro-pyrimidine-5-carbonitrile.

A series of dihydro-pyrimidine-5-carbonitrile derivatives (3-16) were synthesized and evaluated for their anticonvulsant activity against MES and scPTZ models. Motor impairment screening was carried out by rotarod test method and CNS depressant effect was determined by Porsolt's force swim pool method. Compounds 4 and 9 having p-substituted bromo and m-substituted nitro groups, respectively, were found to be most active showing activity both in MES and scPTZ screen at lower doses of 30 mgkg(-1) at 0.5 h and 100 mgkg(-1) at 4 h. In the rotarod motor impairment screen, compound 4 did not show any motor impairment even at the maximum dose of 300 mgkg(-1); however, compound 9 showed motor impairment at 300 mgkg(-1) dose after 4.0 h. The compounds were also tested for their CNS depression effect. The compounds 4 and 9 showed 41.38 and 43.44% increase in immobility time with respect to control. The pharmacophore hypothesis also fits best for compounds 4 and 9.

Synthesis, anticonvulsant and neurotoxicity evaluation of some new pyrimidine-5-carbonitrile derivatives.

A series of 2-[2-(substituted benzylidene) hydrazinyl]-4-(4-methoxyphenyl)-6-oxo-1,6-dihydro-pyrimidine-5-carbonitrile (3-16) were synthesized by refluxing 2-hydrazino-4-(4-methoxy-phenyl)-6-oxo-1,6-dihydro-pyrimidine-5-carbonitrile (2) with different substituted aromatic aldehydes in glacial acetic acid and absolute alcohol mixture (8:2). The compounds were evaluated for their anticonvulsant and neurotoxicity effect. In MES test compounds 2-[2-(4-bromo-benzylidene)-hydrazinyl]-4-(4-methoxyphenyl)-6-oxo-1,6-dihydro-pyrimidine-5-carbonitrile (5), 2-[2-(4-hydroxy-benzylidene)-hydrazinyl]-4-(4-methoxyphenyl)-6-oxo-1,6-dihydro-pyrimidine-5-carbonitrile (9), and 2-[2-(3-fluoro-benzylidene)-hydrazinyl]-4-(4-methoxyphenyl)-6-oxo-1,6-dihydro-pyrimidine-5-carbonitrile (16) were found to be highly active at a dose level of 30 mgkg(-1) at 0.5 h time interval, indicating their ability to prevent seizure spread at a relatively low dose.

Synthesis of some new 2-(substituted-phenyl)-5-(N,N-diphenylaminomethyl)-1,3,4-oxadiazoles: a safer anti-inflammatory and analgesic agents.

A series of 2-(substituted-phenyl)-5-(N,N-diphenylaminomethyl)-1,3,4-oxadiazoles (3-15) were synthesized. The compounds were evaluated for their anti-inflammatory, analgesic, ulcerogenic and lipid peroxidation actions. The percentage inhibition in edema at different time intervals indicated that compounds 8, 11, 12, 14 and 15 exhibited good anti-inflammatory potential. The results illustrate that 2-(2-acetoxyphenyl)-5-(N,N-diphenylaminomethyl)-1,3,4-oxadiazole (15) and 2-(3,4-dimethoxyphenyl)-5-(N,N-diphenylaminomethyl)-1,3,4-oxadiazole (12) showed best anti-inflammatory activity among the series tested. Furthermore, activity is higher in case of chloro substitution as compared to methyl substitution. The compounds synthesized were also evaluated for their ulcerogenic and lipid peroxidation action and showed superior GI safety profile along with reduction in lipid peroxidation as compared to that of ibuprofen.

Synthesis and in vitro antimicrobial evaluation of condensed heterocyclic 6-substituted 1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazole and 1,3,4-oxadiazole derivatives of isoniazid.

A series of 6-substituted-1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazole (3a-g) and 1,3,4-oxadiazole (4a-g, 5) derivatives of isoniazid were synthesized in satisfactory yield and pharmacologically evaluated for their in vitro antimicrobial activity. All the synthesized compounds were in good agreement with elemental and spectral data. A majority of the tested compounds showed good to moderate antimicrobial activity against all tested pathogenic bacterial and fungal strains.

N'-[(5-chloro-3-methyl-1-phenyl-1H-pyrazol-4-yl)methylene] 2/4-substituted hydrazides: synthesis and anticonvulsant activity.

A series of N'-[(5-chloro-3-methyl-1-phenyl-1H-pyrazol-4-yl)methylene] 2/4-substituted hydrazides were synthesized using appropriate synthetic route and characterized by elemental analysis and spectral data. The anticonvulsant activity of some of the synthesized compounds were evaluated against maximal electroshock induced seizure (MES) and subcutaneous pentylenetetrazol (scPTZ) induced seizure models in mice. The neurotoxicity were assessed using the rotorod method. All the test compounds were administered at doses of 30, 100, and 300 mg/kg body weight and the anticonvulsant activity was noted at 0.5 and 4 h time intervals after the drug administration. Among the compound tested, all except 5 g showed protection from seizures in both the animal models. Some titled compounds exhibited lesser CNS depression and neurotoxicity compared to phenytoin.

Design & synthesis of 2-(substituted aryloxy)-5-(substituted benzylidene)-3-phenyl-2,5-dihydro-1H-[1,2,4] triazin-6-one as potential anticonvulsant agents.

A series of 2-(substituted aryloxy)-5-(substituted benzylidene)-3-phenyl-2,5-dihydro-1H-[1,2,4] triazin-6-one were designed & synthesized using appropriate synthetic route keeping in view the structural requirement of pharmacophore and evaluated for anticonvulsant activity and CNS activities. After intraperitoneal injection to mice, some synthesized derivatives were examined in the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazol (scPTZ) induced seizure and neurotoxicity screens. Those found potent were also evaluated for behavioural impairment and depression activity. Among the compound tested, 5 eIX showed protection from seizures in both the animal models at dose level of 30 mg/kg while 5 bII &5 cII showed protection against scPTZ model at same dose level. Some titled compounds exhibited lesser CNS depression and neurotoxicity compared to clinically effective drug.

Anticonvulsant activity of bacopa monniera in rodents / Anticonvulsivante atividade de bacopa monniera em roedores

Bacopa monnieri (L), belonging to the Scrophulariaceae family and commonly known as Brahmi, is well known in India for its CNS activity but its neuropharmacological effect has not yet been explored. In the present study, the antiepileptic effects of the plant were investigated. The ethanolic extract of Bacopa monniera was tested for anticonvulsant activity in albino rats, using different convulsive models. The ethanolic extract of leaves produced significant anticonvulsant activity for all the different models studied. The present study shows a probable mechanism of action similar to that of benzodiazepines (GABA agonist). Thus, these results emphasize the need to diversify by using alternative therapeutic approaches pertaining to herbal medicine, where a single easily available plant may provide solutions to several therapeutic challenges, as observed in the anticonvulsant action of ethanolic extract of B. monniera.

Bacopa monniera, da família Scrophulariaceae, e comumente denominada Brahmi, é bem conhecida na Índia por sua atividade no Sistema Nervoso Central, mas seu efeito neurofarmacológico não foi, ainda, explorado. No presente estudo, investigaram-se os efeitos antiepilépticos da planta. O extrato etanólico da Bacopa monniera foi testado quanto à atividade anticonvulsivante em ratos albinos, utilizando-se diferentes modelos de convulsão. O extrato etanólico das folhas produziu atividade anticonvulsivante significativa para todos os diferentes modelos estudados. O presente estudo mostra provável mecanismo de ação semelhante ao dos benzodiazepínicos (agonista do GABA). Assim sendo, esses resultados enfatizam a necessidade de diversificar, utilizando-se abordagens terapêuticas alternativas da medicina natural, em que uma planta facilmente disponível pode fornecer soluções para vários desafios terapêuticos, como o observado na ação anticonvulsivante do extrato etanólico de Bacopa monniera.

Synthesis and antihyperglycemic activity of 2-(substituted phenyl)-3-{[4-(1-naphthyl)-1,3-thiazol-2-yl] amino}-4-oxo-1,3-thiazolidin-5-ylacetic acid derivatives.

The title compounds were prepared by brominating 1-acetylnaphthalene in chloroform followed by condensation with substituted benzaldehyde thiosemicarbazones using ethanol to get 4-naphthalen-1-yl-2-{2-[(substituted phenyl)methylidene]hydrazino}-1,3-thiazoles. These thiazole derivatives were then cyclized to title compounds by reacting with thiomalic acid in dioxane using ZnCl2. All the synthesized compounds were characterized on the basis of their IR, 1H NMR, and elemental analysis. The antihyperglycemic study was divided into two phases. Phase-I involved evaluation of blood glucose lowering ability of thiazolidinones in normal rats by sucrose-loaded model (SLM). Phase-II study included the evaluation of blood sugar by alloxan model.