Unique PFK regulatory property from some mosquito vectors of disease, and from Drosophila melanogaster

Effect of F2, 6BP on Aedes aegypti PFK activity. PFK activity was measured at pH = 7.4, 1 mM F6P, 5 mM ATP at several F2, 6BP concentrations (0.01–50 μM). Values are the means ± SEM of three independent experiments. (TIF 466 kb

Molecular docking and molecular dynamicsof semi-synthetic piperidine alkaloids as acetylcholinesterase inhibitors

A mistura dos derivados semissintéticos cloridrato da (–)-3-O-acetil-cassina e cloridrato da (–)-3-O-acetil-espectalina, preparada a partir da mistura dos alcalóides (–)-cassina e (–)-espectalina (4:1) obtida de Senna spectabilis, é um potente inibidor da acetilcolinesterase (AChE), assim justificando mais estudos moleculares. Neste sentido, estudos de docking e dinâmica moleculares foram conduzidos neste trabalho com o objetivo de adquirir uma compreensão mais profunda de todos os aspectos estruturais das moléculas cloridratos da (–)-3-O-acetil-cassina e (–)-3-O-acetil-espectalina, as quais diferem em seus potenciais inibidores de AChE. Os dois derivados em estudo apresentaram diversas interações com o sítio periférico aniônico dentro da cavidade catalítica de AChE de Torpedo californica. Entretanto, somente o composto majoritário (–)-3-O-acetil-cassina mostrou interação com a tríade catalítica de maneira significativa. As simulações de dinâmica molecular utilizando água como solvente foram importantes para compreender as interações hipotéticas entre cloridratos da (–)-3-O-acetil-cassina e (–)-3-O-acetil-espectalina com AChE. Os dados obtidos indicam que o composto (–)-3-O-acetil-cassina é o inibidor da enzima mais potente possivelmente devido às suas interações favoráveis com a proteína, com menor custo de dessolvatação. Estes resultados sugerem que o tamanho da cadeia lateral influencia no potencial inibitório das moléculas avaliadas e podem representar o ponto de partida para o desenvolvimento de novos derivados de (–)-3-O-acetil-cassina, objetivando a descoberta de inibidores de AChE mais eficazes.The mixture of semi-synthetic derivatives (–)-3-O-acetyl-cassine hydrochloride and (–)-3-O-acetyl-spectaline hydrochloride, prepared from the mixture of natural alkaloids (–)-cassine and (–)-spectaline (4:1) isolated from Senna spectabilis, has been shown to be a potent acetylcholinesterase (AChE) inhibitor, thereby prompting further molecular studies. In this sense, docking and dynamic molecular studies were carried out in this work, aiming to acquire a deeper understanding about all the structural aspects of molecules (–)-3-O-acetyl-cassine and (–)-3-O-acetyl-spectaline hydrochlorides, which differ with respect to their AChE inhibitory potentials. Both molecules establish important interactions with the peripheral anionic site within the catalytic gorge of Torpedo californica AChE. However, only the major compound (–)-3-O-acetyl-cassine hydrochloride significantly interacts with the catalytic triad. Explicit-solvent molecular dynamic simulations were conducted in order to gain better understanding about the hypothetical interactions taking place between the semi-synthetic alkaloid molecules (–)-3-O-acetyl-cassine and (–)-3-O-acetyl-spectaline hydrochlorides and AChE. The data obtained in this study indicated that (–)-3-O-acetyl-cassine hydrochloride is the most potent inhibitor of AChE possibly due to the favorable interactions of this molecule with the target protein, with lower desolvation cost. These results suggested that the size of the side chain has an effect on the inhibitory potential of the evaluated molecules and may represent the starting point for the development of new derivatives of (–)-3-O-acetyl-cassine hydrochloride, with a view to the discovery of new effective AChE inhibitors

Synthesis and characterization of the atropisomeric relationships of a substituted N-phenyl-bipyrazole derivative with anti-inflammatory properties

This work describes the atropisomeric relationships of 3-methyl-5-(3-methyl-5-phenyl-1H-pyrazol-1-yl)-1-phenyl-1H-pyrazol-4-amine (2d), which belongs to series 4-aminobipyrazole derivatives designed as anti-inflammatory agents. The 1H nuclear magnetic resonance spectra obtained in the presence of a chiral lanthanide shift salt associated to chiral high-performance liquid chromatography analysis, X-ray diffraction, and molecular modeling tools confirmed that ortho bis-functionalized bipyrazole 2d exists as a mixture of aR,aS-atropisomers. These results provide useful information to understand the pharmacological profile of this derivative and of other 4-aminobipyrazole analogs. Chirality 24:463470, 2012. (c) 2012 Wiley Periodicals, Inc.CAPES (BR.)CAPES (BR.)CNPq (BR.)CNPq (BR.)FINEP (BR.)FINEP (BR.)FAPERJ (BR.)FAPERJ (BR.

Molecular Docking and Molecular Dynamic Studies of Semi-Synthetic Piperidine Alkaloids as Acetylcholinesterase Inhibitors

The mixture of semi-synthetic derivatives (-)-3-O-acetyl-cassine hydrochloride and (-)-3-O-acetyl-spectaline hydrochloride, prepared from the mixture of natural alkaloids (-)-cassine and (-)-spectaline (4:1) isolated from Senna spectabilis, has been shown to be a potent acetylcholinesterase (AChE) inhibitor, thereby prompting further molecular studies. In this sense, docking and dynamic molecular studies were carried out in this work, aiming to acquire a deeper understanding about all the structural aspects of molecules (-)-3-O-acetyl-cassine and (-)-3-O-acetyl-spectaline hydrochlorides, which differ with respect to their AChE inhibitory potentials. Both molecules establish important interactions with the peripheral anionic site within the catalytic gorge of Torpedo californica AChE. However, only the major compound (-)-3-O-acetyl-cassine hydrochloride significantly interacts with the catalytic triad. Explicit-solvent molecular dynamic simulations were conducted in order to gain better understanding about the hypothetical interactions taking place between the semi-synthetic alkaloid molecules (-)-3-O-acetyl-cassine and (-)-3-O-acetyl-spectaline hydrochlorides and AChE. The data obtained in this study indicated that (-)-3-O-acetyl-cassine hydrochloride is the most potent inhibitor of AChE possibly due to the favorable interactions of this molecule with the target protein, with lower desolvation cost. These results suggested that the size of the side chain has an effect on the inhibitory potential of the evaluated molecules and may represent the starting point for the development of new derivatives of (-)-3-O-acetyl-cassine hydrochloride, with a view to the discovery of new effective AChE inhibitors.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Molecular docking and molecular dynamicsof semi-synthetic piperidine alkaloids as acetylcholinesterase inhibitors

A mistura dos derivados semissintéticos cloridrato da (–)-3-O-acetil-cassina e cloridrato da (–)-3-O-acetil-espectalina, preparada a partir da mistura dos alcalóides (–)-cassina e (–)-espectalina (4:1) obtida de Senna spectabilis, é um potente inibidor da acetilcolinesterase (AChE), assim justificando mais estudos moleculares. Neste sentido, estudos de docking e dinâmica moleculares foram conduzidos neste trabalho com o objetivo de adquirir uma compreensão mais profunda de todos os aspectos estruturais das moléculas cloridratos da (–)-3-O-acetil-cassina e (–)-3-O-acetil-espectalina, as quais diferem em seus potenciais inibidores de AChE. Os dois derivados em estudo apresentaram diversas interações com o sítio periférico aniônico dentro da cavidade catalítica de AChE de Torpedo californica. Entretanto, somente o composto majoritário (–)-3-O-acetil-cassina mostrou interação com a tríade catalítica de maneira significativa. As simulações de dinâmica molecular utilizando água como solvente foram importantes para compreender as interações hipotéticas entre cloridratos da (–)-3-O-acetil-cassina e (–)-3-O-acetil-espectalina com AChE. Os dados obtidos indicam que o composto (–)-3-O-acetil-cassina é o inibidor da enzima mais potente possivelmente devido às suas interações favoráveis com a proteína, com menor custo de dessolvatação. Estes resultados sugerem que o tamanho da cadeia lateral influencia no potencial inibitório das moléculas avaliadas e podem representar o ponto de partida para o desenvolvimento de novos derivados de (–)-3-O-acetil-cassina, objetivando a descoberta de inibidores de AChE mais eficazes.The mixture of semi-synthetic derivatives (–)-3-O-acetyl-cassine hydrochloride and (–)-3-O-acetyl-spectaline hydrochloride, prepared from the mixture of natural alkaloids (–)-cassine and (–)-spectaline (4:1) isolated from Senna spectabilis, has been shown to be a potent acetylcholinesterase (AChE) inhibitor, thereby prompting further molecular studies. In this sense, docking and dynamic molecular studies were carried out in this work, aiming to acquire a deeper understanding about all the structural aspects of molecules (–)-3-O-acetyl-cassine and (–)-3-O-acetyl-spectaline hydrochlorides, which differ with respect to their AChE inhibitory potentials. Both molecules establish important interactions with the peripheral anionic site within the catalytic gorge of Torpedo californica AChE. However, only the major compound (–)-3-O-acetyl-cassine hydrochloride significantly interacts with the catalytic triad. Explicit-solvent molecular dynamic simulations were conducted in order to gain better understanding about the hypothetical interactions taking place between the semi-synthetic alkaloid molecules (–)-3-O-acetyl-cassine and (–)-3-O-acetyl-spectaline hydrochlorides and AChE. The data obtained in this study indicated that (–)-3-O-acetyl-cassine hydrochloride is the most potent inhibitor of AChE possibly due to the favorable interactions of this molecule with the target protein, with lower desolvation cost. These results suggested that the size of the side chain has an effect on the inhibitory potential of the evaluated molecules and may represent the starting point for the development of new derivatives of (–)-3-O-acetyl-cassine hydrochloride, with a view to the discovery of new effective AChE inhibitors

CNS-selective noncompetitive cholinesterase inhibitors derived from the natural piperidine alkaloid (-)-spectaline

LASSBio-767 [(-)-3-O-acetyl-spectaline] and LASSBio-822 [(-)-3-O-tert-Boc-spectaline] were recently described as cholinesterase inhibitors derived from the natural piperidine alkaloid (-)-spectaline, obtained from the flowers of Senna spectabilis (Fabaccae). We investigated their mechanism of inhibition of acetylcholinesterase and their efficacy in reversing scopolamine-induced amnesia. Competition assays with the substrate acetylthiocholine showed a concentration-dependent reduction in rat brain cholinesterase V-max without changes in apparent K-m. The kinetic data for LASSBio-767 and LASSBio-822 were best fit by a model of simple linear noncompetitive inhibition with K-i of 6.1 mu M and 7.5 mu M, respectively. A dilution assay showed a fast and complete reversal of inhibition, independent of incubation time. Simulated docking of the compounds into the catalytic gorge of Torpedo acetylcholinesterase showed interactions with the peripheral anionic site, but not with the catalytic triad. Anti-amnestic effects in mice were assessed in a step-down passive avoidance test and in the Morris water maze 30 min after injection of scopolamine (1 mg/kg i.p.). Saline, LASSBio-767, or LASSBio-822 was administered 15 min before scopolamine. Both compounds reversed the scopolamine-induced reduction in step-down latency at 0.1 mg/kg i.p. LASSBio-767 reversed scopolamine-induced changes in water maze escape latency at 1 mg/kg i.p. or p.o., while its cholinergic side effects were absent or mild up to 30 mg/kg i.p. (LD50 above 100 mg/kg i.p.). Thus, the (-)-spectaline derivatives are potent cholinergic agents in vivo, with a unique profile combining noncompetitive cholinesterase inhibition and CNS selectivity, with few peripheral side effects. (C) 2007 Elsevier B.V. All rights reserved