Anticonvulsants containing the N-(3-aryl-2-propenoyl) amido pharmacophore

Anticonvulsant Properties of 1-Diethylamino-3-phenylprop-2-en-1-one

There is a need for novel antiepileptic agents whose modes of action differ from those of current antiepileptic drugs. The objective of this study was to determine whether 1-diethylamino-3-phenylprop-2-en-1-one (2) could prevent or at least diminish convulsions caused by different mechanisms. This amide afforded protection in the maximal electroshock and subcutaneous pentylenetetrazole screens when given intraperitoneally to both mice and rats. A number of specialized tests in mice were conducted and are explained in the text. They revealed (2) to have efficacy in the 6 Hz psychomotor seizure test, the corneal kindling model, the mouse temporal epilepsy screen and a peripheral neuronal transmission test using formalin. Three screens in rats were undertaken, which revealed that (2) blocked chloride channels, inhibited peripheral neuronal transmission (tested using sciatic ligation and von Frey fibres) and afforded protection in the lamotrigine-resistant kindled rat model. The biodata generated reveal that (2) is an important lead molecule in the quest for novel structures to combat epilepsy.

S(+)-(2E)-N-(2-Hydroxypropyl)-3-Phenylprop-2-Enamide (KM-568): A Novel Cinnamamide Derivative with Anticonvulsant Activity in Animal Models of Seizures and Epilepsy

Epilepsy is one of the most frequent neurological disorders affecting about 1% of the world’s human population. Despite availability of multiple treatment options including antiseizure drugs, it is estimated that about 30% of seizures still remain resistant to pharmacotherapy. Searching for new antiseizure and antiepileptic agents constitutes an important issue within modern medicinal chemistry. Cinnamamide derivatives were identified in preclinical as well as clinical studies as important drug candidates for the treatment of epilepsy. The cinnamamide derivative presented here: S(+)-(2E)-N-(2-hydroxypropyl)-3-phenylprop-2-enamide (S(+)-N-(2-hydroxypropyl)cinnamamide, compound KM-568) showed anticonvulsant activity in several models of epilepsy and seizures in mice and rats. It was active in a genetic animal model of epilepsy (Frings audiogenic seizure-susceptible mouse model, ED₅₀ = 13.21 mg/kg, i.p.), acute seizures induced electrically (maximal electroshock test ED₅₀ = 44.46 mg/kg mice i.p., ED₅₀ = 86.6 mg/kg mice p.o., ED₅₀ = 27.58 mg/kg rats i.p., ED₅₀ = 30.81 mg/kg rats p.o., 6-Hz psychomotor seizure model 32 mA ED₅₀ = 71.55 mg/kg mice i.p., 44 mA ED₅₀ = 114.4 mg/kg mice i.p.), chronic seizures induced electrically (corneal kindled mouse model ED₅₀ = 79.17 mg/kg i.p., hippocampal kindled rat model ED₅₀ = 24.21 mg/kg i.p., lamotrigine-resistant amygdala kindled seizure model in rats ED₅₀ = 58.59 mg/kg i.p.), acute seizures induced chemically (subcutaneous metrazol seizure threshold test ED₅₀ = 104.29 mg/kg mice i.p., ED₅₀ = 107.27 mg/kg mice p.o., ED₅₀ = 41.72 mg/kg rats i.p., seizures induced by picrotoxin in mice ED₅₀ = 94.11 mg/kg i.p.) and the pilocarpine-induced status epilepticus model in rats (ED₅₀ = 279.45 mg/kg i.p., ED₉₇ = 498.2 mg/kg i.p.). The chemical structure of the compound including configuration of the chiral center was confirmed by NMR spectroscopy, LC/MS spectroscopy, elemental analysis, and crystallography. Compound KM-568 was identified as a moderately stable derivative in an in vitro mouse liver microsome system. According to the Ames microplate format mutagenicity assay performed, KM-568 was not a base substitution or frameshift mutagen. Cytotoxicity evaluation in two cell lines (HepG2 and H9c2) proved the safety of the compound in concentrations up to 100 µM. Based on the results of anticonvulsant activity and safety profile, S(+)-(2E)-N-(2-hydroxypropyl)-3-phenylprop-2-enamide could be proposed as a new lead compound for further preclinical studies on novel treatment options for epilepsy.

Cinnamamide pharmacophore for anticonvulsant activity: evidence from crystallographic studies

A number of cinnamamide derivatives possess anticonvulsant activity due to the presence of a number of important pharmacophore elements in their structures. In order to study the correlations between anticonvulsant activity and molecular structure, the crystal structures of three new cinnamamide derivatives with proven anticonvulsant activity were determined by X-ray diffraction, namely (R,S)-(2E)-N-(2-hydroxybutyl)-3-phenylprop-2-enamide-water (3/1), C₁₃H₁₇NO₂·0.33H₂O, (1), (2E)-N-(1-hydroxy-2-methylpropan-2-yl)-3-phenylprop-2-enamide, C₁₃H₁₇NO₂, (2), and (R,S)-(2E)-N-(1-hydroxy-3-methyl-butan-2-yl)-3-phenylprop-2-enamide, C₁₄H₁₉NO₂, (3). Compound (1) crystallizes in the space group P-1 with three molecules in the asymmetric unit, whereas compounds (2) and (3) crystallize in the space group P2₁/c with one and two molecules, respectively, in their asymmetric units. The carbonyl group of (2) is engaged in an intramolecular hydrogen bond with the hydroxy group. This type of interaction is observed for the first time in these kinds of derivatives. A disorder of the substituent at the N atom occurs in the crystal structures of (2) and (3). The crystal packing of all three structures is dominated by a network of O-H...O and N-H...O hydrogen bonds, and leads to the formation of chains and/or rings. Furthermore, the crystal structures are stabilized by numerous C-H...O contacts. We analyzed the molecular structures and intermolecular interactions in order to propose a pharmacophore model for cinnamamide derivatives.

Physicochemical and biological evaluation of a cinnamamide derivative R,S-(2E)-1-(3-hydroxypiperidin-1-yl)-3-phenylprop-2-en-1-one (KM-608) for nervous system disorders

A cinnamamide scaffold has been successfully incorporated in several compounds possessing desirable pharmacological activities in central and peripheral nervous system such as anticonvulsant, antidepressant, neuroprotective, analgesic, anti-inflammatory, muscle relaxant, and sedative/hypnotic properties. R,S-(2E)-1-(3-hydroxypiperidin-1-yl)-3-phenylprop-2-en-1-one (KM-608), a cinnamamide derivative, was synthesized, its chemical structure was confirmed by means of spectroscopy and crystallography, and additionally, thermal analysis showed that it exists in one crystalline form. The compound was evaluated in vivo in rodents as anticonvulsant, antiepileptogenic, analgesic, and neuroprotective agent. The beneficial properties of the compound were found in animal models of seizures evoked electrically (maximal electroshock test, 6-Hz) and chemically (subcutaneous pentylenetetrazole seizure test) as well as in three animal models of epileptogenesis: corneal-kindled mice, hippocampal-kindled rats, and lamotrigine-resistant amygdala-kindled rats. Quantitative pharmacological parameters calculated for the tested compound were comparable to those of currently used antiepileptic drugs. In vivo pharmacological profile of KM-608 corresponds with the activity of valproic acid.

Structure-anticonvulsant activity studies in the group of (E)-N-cinnamoyl aminoalkanols derivatives monosubstituted in phenyl ring with 4-Cl, 4-CH3 or 2-CH3

A series of twenty two (E)-N-cinnamoyl aminoalkanols derivatives monosubstituted in phenyl ring with 4-Cl, 4-CH₃ or 2-CH₃ was designed, synthesized and evaluated for anticonvulsant activity in rodent models of seizures: maximal electroshock (MES) test, subcutaneous pentylenetetrazole (scPTZ) test, and 6-Hz test. There were identified three most active compounds: S-(2E)-N-(1-hydroxypropan-2-yl)-3-(2-methylphenyl)prop-2-enamide (5) (ED₅₀ MES=42.56, ED₅₀ scPTZ=58.38, ED₅₀ 6-Hz 44mA=42.27mg/kg tested in mice after intraperitoneal (i.p.) administration); R,S-(2E)-3-(4-chlorophenyl)-N-(1-hydroxybutan-2-yl)prop-2-enamide (6) (ED₅₀ MES=53.76, ED₅₀ scPTZ=90.31, ED₅₀ 6-Hz 44mA=92.86mg/kg mice, i.p.); and R,S-(2E)-3-(4-chlorophenyl)-N-(2-hydroxypropyl)prop-2-enamide (11) (ED₅₀ MES=55.58, ED₅₀ scPTZ=102.15, ED₅₀ 6-Hz 44mA=51.27mg/kg mice, i.p.). Their structures and configurations were confirmed by crystal X-ray diffraction method. The structure-activity studies among the tested series showed that chlorine atom in position para or methyl group in position ortho of phenyl ring were beneficial for anticonvulsant activity. Methyl group in position para of phenyl ring decreased anticonvulsant activity in reported series of cinnamamide derivatives.

Anticonvulsant activity, crystal structures, and preliminary safety evaluation of N-trans-cinnamoyl derivatives of selected (un)modified aminoalkanols

Adequate control of seizures remains an unmet need in epilepsy. In order to identify new anticonvulsant agents, a series of N-trans-cinnamoyl derivatives of selected aminoalkanols was synthetized. The compounds were obtained in the reaction of N-acylation carried out in a two-phase system. The substances were tested in animal models of seizures induced either electrically (maximal electroshock--MES; 6-Hz test) or chemically, by subcutaneous injection of pentetrazol (scPTZ). Neurotoxicity was determined by the rotarod test. Lipophilicity of the active compounds, expressed as RM0, was determined by reversed-phase thin layer chromatography and it ranged from 1.390 to 2.219. From among the tested series of compounds, R,S-(E)-N-(1-hydroxypropan-2-yl)-3-phenylprop-2-enamide (1) and R,S-(E)-N-(2-hydroxypropyl)-3-phenylprop-2-enamide (3) exhibited the best anticonvulsant activity. Compound 1, when administered to mice by intraperitoneal (i.p.) injection, showed the ED50 values of 86.6, 60.9, and 109.6 mg/kg in the MES, 6-Hz, and scPTZ tests, respectively. For compound 3, the ED50 values were found to be 47.1 mg/kg in MES and 77.1 mg/kg in scPTZ (mice, i.p.). The distances measured in crystals of compound 1 were: 7.99 Å--from the phenyl ring to the hydroxyl group in the amide moiety, 5.729 Å--from the phenyl ring to the amide group, and 3.112 Å--from the amide group to the hydroxyl group in the amide moiety. The reported compounds did not exhibit mutagenic potential when assayed in the Ames test. Compounds 1 and 3 did not affect viability and morphology of human hepatocellular carcinoma cells (HepG2).

Cinnamamide Derivatives for Central and Peripheral Nervous System Disorders--A Review of Structure-Activity Relationships

The cinnamamide scaffold has been incorporated in to the structure of numerous organic compounds with therapeutic potential. The scaffold enables multiple interactions, such as hydrophobic, dipolar, and hydrogen bonding, with important molecular targets. Additionally, the scaffold has multiple substitution options providing the opportunity to optimize and modify the pharmacological activity of the derivatives. In particular, cinnamamide derivatives have exhibited therapeutic potential in animal models of both central and peripheral nervous system disorders. Some have undergone clinical trials and were introduced on to the pharmaceutical market. The diverse activities observed in the nervous system included anticonvulsant, antidepressant, neuroprotective, analgesic, anti-inflammatory, muscle relaxant, and sedative properties. Over the last decade, research has focused on the molecular mechanisms of action of these derivatives, and the data reported in the literature include targeting the γ-aminobutyric acid type A (GABAA ) receptors, N-methyl-D-aspartate (NMDA) receptors, transient receptor potential (TRP) cation channels, voltage-gated potassium channels, histone deacetylases (HDACs), prostanoid receptors, opioid receptors, and histamine H3 receptors. Here, the literature data from reports evaluating cinnamic acid amide derivatives for activity in target-based or phenotypic assays, both in vivo and in vitro, relevant to disorders of the central and peripheral nervous systems are analyzed and structure-activity relationships discussed.

1,3-diaryl-2-propenones and 2-benzylidene-1,3-indandiones: a quest for compounds displaying greater toxicity to neoplasms than normal cells

A series of 1,3-diaryl-2-propenones 2a-j and analogous 2-benzylidene-1,3-indandiones 3a-j were evaluated against various neoplasms and normal cells. In general, greater cytotoxic potencies and selective toxicity to human malignant cells were observed by the compounds in series 2 rather than 3. In particular, 2i emerged as a lead molecule having an average CC(50) figure of 8.6 µM and a selective index value of 18. Various physicochemical features of 2a-j were correlated with the cytotoxic potencies to neoplastic cell lines which provide guidelines for expansion of this series of compounds. The enone 2i induced internucleosomal DNA fragmentation and activated caspase-3 in HL-60 cells suggesting that one of the ways in which the cytotoxicity of the compounds in series 2 is mediated towards some of the cell lines used in this study is by apoptosis. Neurotoxicity in mice was generally lower in series 2 than 3a-j.