RESUMO
In this study we addressed the role of chirality in the biological activity of RC-33, recently studied by us in its racemic form. An asymmetric synthesis procedure was the first experiment, leading to the desired enantioenriched RC-33 but with an enantiomeric excess (ee) not good enough for supporting the in vitro investigation. An enantioselective high-performance liquid chromatography (HPLC) procedure was then successfully carried out, yielding both RC-33 enantiomers in amounts and optical purity suitable for the pharmacological study. The absolute configuration of pure enantiomers was easily assigned exploiting the asymmetric synthesis previously devised. As emerged in the preliminary in vitro biological investigation, (S)- and (R)-RC-33 possess a comparable affinity towards the σ1 receptor and a very a similar behavior in the calcium influx assay, resulting in an equally effective σ1 receptor agonist. Overall, the results obtained so far suggest that the interaction with the biological target is nonstereoselective and leads us to hypothesize that there is a lack of stereoselectivity in the biological activity of RC-33.
Assuntos
Compostos de Bifenilo/química , Compostos de Bifenilo/farmacologia , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/farmacologia , Piperidinas/química , Piperidinas/farmacologia , Animais , Compostos de Bifenilo/síntese química , Compostos de Bifenilo/isolamento & purificação , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Cobaias , Fármacos Neuroprotetores/síntese química , Fármacos Neuroprotetores/isolamento & purificação , Células PC12 , Piperidinas/síntese química , Piperidinas/isolamento & purificação , Ratos , Receptores sigma/agonistas , EstereoisomerismoRESUMO
Phytochemical investigation on the Amygdalus lycioides Spach branchelets resulted in the isolation of four chiral flavanones: (2R,3R)-Taxifolin, (2R,3R)-aromadendrin, (S)-5,7,3',5'-tetrahydroxyflavanone and (S)-naringenin. The flavanones were isolated by semi-preparative HPLC, their structures elucidated based on spectroscopic data and their absolute configuration assigned. As a part of our ethnobotanical-directed search for novel TNFα inhibitors, the bioassay-guided fractionation of the n-hexane-acetone (n-Hex-Ac, 1:1 v/v) Amygdalus lycioides Spach branchelets extract was performed. In this way, (S)-naringenin was identified as the constituent responsible for the TNFα blocking effect, being effective in vitro and in vivo after oral administration. This is the first investigation on bioactive secondary metabolites of Amygdalus lycioides Spach branchelets.
Assuntos
Flavonóis/química , Prunus/química , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Animais , Cromatografia Líquida de Alta Pressão , Flavonóis/isolamento & purificação , Flavonóis/farmacologia , Camundongos , Espectrometria de Massas por Ionização por Electrospray , Espectrofotometria Ultravioleta , EstereoisomerismoRESUMO
Herein we report the synthesis, drug-likeness evaluation, and in vitro studies of new sigma (σ) ligands based on arylalkenylaminic scaffold. For the most active olefin the corresponding arylalkylamine was studied. Novel arylalkenylamines generally possess high σ(1) receptor affinity (K(i) values <25 nM) and good σ(1)/σ(2) selectivity (K(i)σ(2) >100). Particularly, the piperidine derivative (E)-17 and its arylalkylamine analog (R,S)-33 were observed to be excellent σ(1) receptor ligands (K(i)=0.70 and 0.86 nM, respectively) and to display significantly high selectivity over σ(2), µ-, and κ-opioid receptors and phencyclidine (PCP) binding site of the N-methyl-d-aspartate (NMDA) receptors. Moreover in PC12 cells (R,S)-33 promoted the nerve growth factor (NGF)-induced neurite outgrowth and elongation. Co-administration of the selective σ(1) receptor antagonist BD-1063 totally counteracted this effect, confirming that σ(1) receptors are involved in the (R,S)-33 modulation of the NGF effect in PC12 cells and suggesting a σ(1) agonist profile. As a part of our work, a threedimensional σ(1) pharmacophore model was also developed employing GALAHAD methodology. Only active compounds were used for deriving this model. The model included two hydrophobes and a positive nitrogen as relevant features and it was able to discriminate between molecules with and without affinity toward σ(1) receptor subtype.
Assuntos
Aminas/farmacologia , Fator de Crescimento Neural/metabolismo , Neuritos/efeitos dos fármacos , Receptores sigma/agonistas , Aminas/síntese química , Aminas/química , Animais , Cinética , Ligantes , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Modelos Moleculares , Neuritos/metabolismo , Células PC12 , Ligação Proteica , Ratos , Receptores sigma/metabolismoRESUMO
A microwave-assisted HWE olefination process of readily accessible aryl-alkyl ketones has been developed to provide a rapid access to (Z)-3,3-trisubstituted-alpha,beta-unsaturated methyl esters, key building blocks for the synthesis of biologically active compounds.
Assuntos
Alcenos/síntese química , Ésteres/síntese química , Produtos Biológicos/síntese química , Cetonas/química , Fenômenos de Química Orgânica , EstereoisomerismoRESUMO
In order to investigate the molecular features involved in sigma receptors (sigma-Rs) binding, new compounds based on arylalkylaminoalcoholic, arylalkenyl- and arylalkylaminic scaffolds were synthesized and their affinity towards sigma(1)- and sigma(2)-Rs subtypes was evaluated. The most promising compounds were also screened for their affinity at micro-opioid, delta-opioid and kappa-opioid receptors. Biological results are herein presented and discussed.
Assuntos
Aminas/química , Aminas/farmacologia , Receptores sigma/metabolismo , Alcenos/química , Alcenos/farmacologia , Amino Álcoois/química , Amino Álcoois/farmacologia , Animais , Cobaias , Hidrocarbonetos Aromáticos/química , Hidrocarbonetos Aromáticos/farmacologia , Ligantes , Modelos Moleculares , Ligação Proteica , Ratos , Receptores Opioides/metabolismo , Relação Estrutura-AtividadeRESUMO
Four peptides corresponding to highly conserved motives within the first two RNA recognition motif-type domains of ELAV proteins were prepared, and their effect on the stability of NOVA-1 and VEGF ELAV-target mRNAs was evaluated. Biological results show that in the presence of phorbol 12-myristate 13-acetate (a PKC activator triggering the ELAV pathway), an equimolar mixture of peptides induces a statistically significant stabilization of the selected transcripts, suggesting a synergic effect of the two stimuli.
Assuntos
Antígenos de Neoplasias/genética , Proteínas ELAV/química , Proteínas do Tecido Nervoso/genética , Oligopeptídeos/síntese química , Estabilidade de RNA/efeitos dos fármacos , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética , Fator A de Crescimento do Endotélio Vascular/genética , Motivos de Aminoácidos , Linhagem Celular Tumoral , Sequência Conservada , Ativadores de Enzimas/farmacologia , Humanos , Antígeno Neuro-Oncológico Ventral , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Proteína Quinase C/metabolismo , Acetato de Tetradecanoilforbol/farmacologiaRESUMO
We performed the asymmetric synthesis of four enantiopure benzo[d] isothiazo-3-or 5-yloxypropanolamine derivatives, previously described as competitive antagonists at beta-adrenoceptors. The chemical characterization of each enantiomer was accomplished by (1)H NMR and HPLC/DAD/CD. The direct chromatographic separation of the enantiomers via chiral HPLC was investigated. The best resolutions were achieved using cellulose tris (3,5-dimethylphenyl carbamate) (Chiralcel OD-H) and amylose tris (3,5-dimethylphenyl carbamate) (Chiralpak AD). The enantiomers obtained had enantiomeric purities suitable for biological assays. Tested in isolated rat cardiac and intestinal tissues to evaluate their effects at beta(1)- and beta(3)-adrenoceptors, the (S)-enantiomers revealed a higher degree of antagonism than (R)-enantiomers at both subtypes, even though their activity was greater at the cardiac beta(1)-subtype. The potent and cardiospecific antagonistic effect exerted by the compounds tested suggests that the benzisothiazole moiety could be an interesting scaffold for discovering new chiral beta-blocking drugs.
Assuntos
Antagonistas Adrenérgicos/síntese química , Antagonistas Adrenérgicos/farmacologia , Propanolaminas/síntese química , Propanolaminas/farmacologia , Tiazóis/síntese química , Tiazóis/farmacologia , Antagonistas Adrenérgicos/química , Antagonistas Adrenérgicos/isolamento & purificação , Animais , Cromatografia , Cromatografia Líquida de Alta Pressão , Dicroísmo Circular , Átrios do Coração/efeitos dos fármacos , Átrios do Coração/metabolismo , Íleo/efeitos dos fármacos , Íleo/metabolismo , Masculino , Propanolaminas/química , Propanolaminas/isolamento & purificação , Ratos , Estereoisomerismo , Especificidade por Substrato , Tiazóis/química , Tiazóis/isolamento & purificaçãoRESUMO
We describe here the synthesis and the binding interaction with sigma(1) and sigma(2) receptors of a series of new benzo[d]oxazol-2(3H)-one derivatives variously substituted on the N-benzyl moiety. The results of binding studies confirm the notion that the benzoxazolone moiety confers preference towards sigma(1) sites and establish that the ability to bind to sigma(1), but not to sigma(2) receptors, is strongly affected by the kind and the position of the substituents introduced in the N-benzyl ring. In fact, compounds with substitutions in para-position with atoms of Cl, H or F or with a CH(3) group exhibit a higher affinity for sigma(1) receptors than the corresponding ortho-substituted compounds. The highest affinity and selectivity, with K(i) values of 0.1 and 427 nM for sigma(1) and sigma(2) receptors, respectively, and a corresponding K(i)sigma(2)/K(i)sigma(1) selectivity ratio of 4270 were found for the Cl-substituted compound. These results indicate that benzo[d]oxazol-2(3H)-one derivatives are among the most selective and sigma(1) receptor-preferring ligands currently available.
Assuntos
Benzoxazóis/síntese química , Receptores sigma/metabolismo , Animais , Benzoxazóis/farmacologia , Sítios de Ligação , Ligação Competitiva , Ligantes , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Receptor Sigma-1RESUMO
INTRODUCTION: The extract of Crataegus monogyna shows sedative, hypotensive, vasodilator and cardio-tonic actions. Although several papers dealing with the extraction of metabolites from Crataegus have been published, the plant productivity in terms of bioactive compounds is not easily understandable as yet. OBJECTIVE: To investigate the influence of the extraction mode on the yield of bioactive compounds from Crataegus monogyna Jacq. in order to evaluate plant productivity. METHODOLOGY: Samples were prepared by extraction of powdered material obtained from top branches, flowers and leaves. Soxhlet extraction, maceration and ultrasound- and microwave-assisted extraction at different experimental conditions were investigated for the exhaustive extraction of hyperoside, vitexin and vitexin-2''-O-rhamnoside. The phytocomponents were identified and quantified by HPLC-UV/PAD, comparing HPLC retention times and UV spectra of individual peaks with those of the standards analysed under the same conditions. RESULTS: An easy-to-use HPLC isocratic method suitable for the quantification of hyperoside, vitexin and vitexin-2''-O-rhamnoside in raw plant extracts was developed. The optimised HPLC methodology was applied to evaluate different extraction procedures. The ultrasound and microwave-assisted extraction protocols showed higher extraction efficiency than the others. In particular, the optimised microwave protocol gave rise to the highest extraction efficiency with high reproducibility. CONCLUSIONS: A microwave protocol combined with isocratic HPLC analysis is proposed for the rapid screening of plant materials collected in different environmental conditions in order to evaluate the productivity of Crataegus monogyna Jacq. and to find out the best ecological conditions to cultivate hawthorn in Northern Italy.
Assuntos
Apigenina/análise , Crataegus/química , Quercetina/análogos & derivados , Cromatografia Líquida de Alta Pressão/economia , Cromatografia Líquida de Alta Pressão/métodos , Micro-Ondas , Componentes Aéreos da Planta/química , Quercetina/análise , Solventes/químicaRESUMO
In the attempt to develop new sigma ligands we synthesized a series of N-benzyl-3-[1-(4-fluorophenyl)-1H-indol-3-yl]-N-methylpropan-1-amines and N-benzyl-4-[1-(4-fluorophenyl)-1H-indol-3-yl]-N-methylbutan-1-amines variously substituted on the phenyl ring. The displacement percentages of [3H]-DTG and [3H]-(+)-pentazocine determined in rat liver homogenates by these compounds at the fixed 100 nM concentration have been determined as a preliminary evaluation of their sigma1 and sigma2 affinity, respectively. The results suggested that the phenyl substituents may positively modulate, in comparison with the unsubstituted compound, the ability to displace [3H]-DTG from sigma2 sites, whereas the same phenyl substituents reduced the displacement percentages of [3H]-(+)-pentazocine from sigma1 sites. Some of these compounds were selected for radioligand binding assays. Compounds with a butylene intermediate chain displayed the greatest binding affinity for sigma2 over sigma1 receptors. The butylene derivative with 2,4-dimethyl substitution on the phenyl ring showed the greatest sigma2 affinity (sigma2Ki=5.9 nM) and an appreciable sigma2 over sigma1 selectivity (sigma1Ki/sigma2Ki=22). The obtained results suggest that a butylene chain separating the indole moiety from variously substituted benzylamino groups may be required to their interaction with a hypothetical secondary sigma2 binding site.
Assuntos
Benzeno/química , Indóis/química , Indóis/metabolismo , Receptores sigma/metabolismo , Animais , Sítios de Ligação , Ligação Proteica , Ratos , Especificidade por SubstratoRESUMO
A new series of arylalkyl- and alkenylamines was designed, synthesized, and evaluated for binding to sigma(1) and sigma(2) receptors. Many compounds exhibited nanomolar affinity for sigma(1) subtype receptor with good selectivity over sigma(2). A molecular modeling study was conducted in order to rationalize the experimental data, and the structure-receptor affinities are discussed.
Assuntos
Receptores sigma/efeitos dos fármacos , Animais , Encéfalo/metabolismo , Fenômenos Químicos , Físico-Química , Cromatografia em Camada Fina , Desenho de Fármacos , Cobaias , Técnicas In Vitro , Indicadores e Reagentes , Espectroscopia de Ressonância Magnética , Membranas/metabolismo , Modelos Moleculares , Conformação Molecular , Ensaio Radioligante , Relação Estrutura-Atividade , Receptor Sigma-1RESUMO
The diastereoselective synthesis via Grignard reaction of enantiopure analgesic naphthylaminoalcohols has been performed. The chiral racemic key intermediate 3-dimethylamino-2-methyl-1-(naphthalen-2-yl)propan-1-one and enantiomers were prepared and transformed into the desired compounds by addition of the organometallic reagent. The chemical characterization of all diastereoisomers was accomplished by 1H NMR and HPLC analyses and the absolute configuration assigned by CD spectroscopy. The in vitro and in vivo profile has also been evaluated.
Assuntos
Álcoois/química , Álcoois/farmacologia , Analgésicos Opioides/química , Analgésicos Opioides/farmacologia , Dor/prevenção & controle , Álcoois/síntese química , Aminação , Analgésicos Opioides/síntese química , Animais , Dicroísmo Circular , Temperatura Alta , Espectroscopia de Ressonância Magnética , Masculino , Camundongos , Estrutura Molecular , EstereoisomerismoRESUMO
We describe the preparation of racemic N,N-dimethyl-3-(naphthalen-2-yl)-butan-1-amines, potential sigma1 ligands, and their resolution via chiral HPLC. In order to obtain enantiopure compounds, direct chromatographic methods of separation using chiral stationary phases were investigated. Different methods suitable for both analytical and semipreparative purposes are proposed. The best resolutions were achieved using cellulose tris (3,5-dimethylphenyl carbamate) (Chiralcel OD and OD-H) and amylose tris (3,5-dimethylphenyl carbamate) (Chiralpak AD). On the basis of the preliminary chromatographic results, the resolution of compound 1 was transferred onto a Chiralcel OD semipreparative column. The enantiomers were obtained in high enantiomeric excess. The configurational assignment was performed by circular dichroism. Computational analysis was used to explore the enantioselective recognition process of compound 1 with the Chiralcel OD stationary phase.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Aminas/análise , Aminas/química , Amilose/análogos & derivados , Amilose/química , Celulose/análogos & derivados , Celulose/química , Dicroísmo Circular , Ligantes , Modelos Moleculares , Estrutura Molecular , Naftalenos/análise , Naftalenos/química , Fenilcarbamatos/química , EstereoisomerismoRESUMO
The preparation and biological evaluation of a new class of arylpyrrolidinols is reported. The antinociceptive activity was evaluated in vivo with the hot plate test (HPT) and formalin test (FT), excluding any involvement on motor coordination with the rota-rod test (RRT). The nociceptive behavior in the late phase of FT (representative of chronic pain) suggests an involvement of the antiinflammatory process and it is clearly influenced by the stereochemical features, being the eutomer of phenylpyrrolidinols, the (2R,3S) enantiomer. Despite this, a specific mechanism of action is not yet clarified.
Assuntos
Analgésicos/síntese química , Analgésicos/uso terapêutico , Pirrolidinas/síntese química , Pirrolidinas/uso terapêutico , Analgésicos/química , Animais , Cristalografia por Raios X , Masculino , Camundongos , Modelos Moleculares , Conformação Molecular , Dor/tratamento farmacológico , Medição da Dor/efeitos dos fármacos , Pirrolidinas/químicaRESUMO
In the present paper, we report on the synthesis and antinociceptive activity of a new series of N-methyl-arylpyrrolidinols that we designed for a rational structure-activity relationship (SAR) study. The antinociceptive properties were investigated in vivo by the hot plate and formalin tests in mice and control on the locomotory activity was also monitored by the rota rod test. With this aim, the evaluation of the lipophilicity of all compounds was performed by the Daylight computational method in order to better understand the SAR. Interesting properties were proven for the compounds of the entire series.
Assuntos
Analgésicos/farmacologia , Pirrolidinas/farmacologia , Analgésicos/síntese química , Animais , Anti-Inflamatórios/síntese química , Anti-Inflamatórios/farmacologia , Comportamento Animal/efeitos dos fármacos , Masculino , Camundongos , Atividade Motora/efeitos dos fármacos , Medição da Dor , Pirrolidinas/síntese química , Relação Estrutura-AtividadeRESUMO
The synthesis and biological evaluation of a series of new derivatives of 2-substituted 5-phenyl-1,4-benzodiazepines, structurally related to tifluadom (5), are reported. Chemical and pharmacological studies on compounds 6 have been pursued with the aim of expanding the SAR data and validating the previously proposed model of interaction of this class of compounds with the kappa-opioid receptor. The synthesis of the previously described compounds 6 has been reinvestigated in order to obtain a more direct synthetic procedure. To study the relationship between the stereochemistry and the receptor binding affinity, compounds 6e and 6k were selected on the basis of their evident structural resemblance to tifluadom. Since a different specificity of action could be expected for the enantiomers of 6e and 6k, owing to the results shown by (S)- and (R)-tifluadom, their racemic mixtures have been resolved by means of liquid chromatography with chiral stationary phases (CSP), and the absolute configuration of the enantiomers has been studied by circular dichroism (CD) and (1)H NMR techniques. Moreover, some new 2-[(acylamino)ethyl]-1,4-benzodiazepine derivatives, 6a-d,f,g,j, have been synthesized, while the whole series (6a-o) has been tested for its potential affinity toward human cloned kappa-opioid receptor. The most impressive result obtained from the binding studies lies in the fact that this series of 2-[2-(acylamino)ethyl]-1,4-benzodiazepine derivatives binds the human cloned kappa-opioid receptor subtype very tightly. Indeed, almost all the ligands within this class show subnanomolar K(i) values, and the least potent compound 6o shows, in any case, an affinity in the nanomolar range. A comparison of the affinities obtained in human cloned kappa-receptor with the correspondent one obtained in native guinea pig kappa-receptor suggests that the human cloned kappa-receptor is less effective in discriminating the substitution pattern than the native guinea pig kappa-receptor. Furthermore, the results obtained are discussed with respect to the interaction with the homology model of the human kappa-opioid receptor, built on the recently solved crystal structure of rhodopsin. Finally, the potential antinociceptive and antiamnesic properties of compounds 6e and 6i have been investigated by means of the hot-plate and passive avoidance test in mice, respectively.