Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Virtual Screening and Biological Evaluation of Piperazine Derivatives as Human Acetylcholinesterase Inhibitors  [PDF]
Kavitha Raj Varadaraju,Jajur Ramanna Kumar,Lingappa Mallesha,Archana Muruli,Kikkeri Narasimha Shetty Mohana,Chethan Kumar Mukunda,Umesha Sharanaiah
International Journal of Alzheimer's Disease , 2013, DOI: 10.1155/2013/653962
Abstract: The piperazine derivatives have been shown to inhibit human acetylcholinesterase. Virtual screening by molecular docking of piperazine derivatives 1-(1,4-benzodioxane-2-carbonyl) piperazine (K), 4-(4-methyl)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S1), and 4-(4-chloro)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S3) has been shown to bind at peripheral anionic site and catalytic sites, whereas 4-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S4) and 4-(2,5-dichloro)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S7) do not bind either to peripheral anionic site or catalytic site with hydrogen bond. All the derivatives have differed in number of H-bonds and hydrophobic interactions. The peripheral anionic site interacting molecules have proven to be potential therapeutics in inhibiting amyloid peptides aggregation in Alzheimer’s disease. All the piperazine derivatives follow Lipinski’s rule of five. Among all the derivatives 1-(1,4-benzodioxane-2-carbonyl) piperazine (K) was found to have the lowest TPSA value. 1. Introduction Acetylcholinesterase (AChE) hydrolyses acetylcholine is associated with nerves and muscles mainly found in synapses. AChE plays an important role in regulation of cholinergic function. It has been shown to be involved in dysfunction of the central cholinergic system in Alzheimer’s disease (AD). It is a progressive neurodegenerative disorder, characterized by an impairment of cognitive function leading to dementia. The main characteristic features of the disease include β-amyloid (Aβ) plaques, neurofibrillary tangles, and their by synaptic loss. AD is estimated to account for about 50–60% dementia cases, in persons over 65 years of age [1]. Symptoms of Alzheimer’s disease include memory loss, language deficit, depression, agitation, and mood disturbances [2–4]. But the exact cause for AD is still not known. Several hypotheses tried to explain the cause of the disease [5]. Among those, the oldest, on which most currently available drug therapies are based, is the cholinergic hypothesis, which proposes that AD is caused by reduced synthesis of the neurotransmitter acetylcholine [1]. Even though the hypothesis failed to get widespread support, but it can be stated that cholinergic scarcity is responsible for the symptoms of AD [5]. This led to the designing and synthesis of AChE inhibitors. The inhibition causes an increase in the concentration of acetylcholine in cholinergic synapse. This might ameliorate the disease symptoms of AD [6, 7]. Tacrine, Donepezil, Rivastigmine,
Rui-Bo Xu,Xing-You Xu,Da-Qi Wang,Xu-Jie Yang
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809045619
Abstract: The molecule of the title compound, C28H42N6, has site symmetry overline{1} with the centroid of the piperazine ring located on an inversion center. The piperazine ring adopts a chair conformation. The benzene ring and propylpiperazine are on opposite sides of the C=N bond, showing an E configuration.
Thermodynamic Investigation and Mixed Ligand Complex Formation of 1,4-Bis-(3-aminopropyl)-piperazine and Biorelevant Ligands  [PDF]
Ahmed A. El-Sherif,Mohamed R. Shehata,Mohamed M. Shoukry,Mohammad H. Barakat
Bioinorganic Chemistry and Applications , 2012, DOI: 10.1155/2012/984291
Abstract: Thermodynamic parameters for protonation of 1,4-bis(3-aminopropyl)-piperazine (BAPP) and its metal complexation with some divalent metal ions were determined in aqueous solution at constant ionic strength (0.1?M NaNO3) using a potentiometric technique. The order of –ΔG0 and –ΔH0 was found to obey , in accordance with the Irving-Williams order. The formation equilibria of zinc (II) complexes and the ternary complexes Zn(BAPP)L, where L?=?amino acid, amides, or DNA constituents), have been investigated. Ternary complexes are formed by a simultaneous mechanism. The concentration distribution of the complexes in solution was evaluated as a function of pH. Stoichiometry and stability constants for the complexes formed are reported and discussed. The stability of ternary complexes was quantitatively compared with their corresponding binary complexes in terms of the parameter Δlog K. 1. Introduction Metal complexes of biologically important ligands are sometimes more effective than free ligands [1]. It is not surprising, therefore, that many authors have studied the coordination compounds of several central atoms. Mixed ligand complexes have a key role in biological chemistry [2] because the mixed chelation occurs commonly in biological fluids as millions of potential ligands are likely to compete for metal ions in vivo [3]. These create specific structures [4] and have been implicated in the storage and transport of active substances through membranes. Among these ligands are piperazine and its derivatives. Some piperazine derivatives were found to inhibit acute human immune deficiency HIV virus from chronically and latently infected cells containing proviral DNA [5]. Also the antimalarial activities of piperazine derivatives are also known [6]. The investigation of metal complexes of piperazine compounds will support their biological activity. The study of ternary complexes of transition metal ions with amino acids, peptides, or DNA units has been the focus of increasing research effort [7–10], which has revealed the role of metal ions at the molecular level. These types of complexes are implicated in the storage and transport of metal ions and of active substances through membranes. So, it is worthwhile to assemble information on their formation, stability, and structure and on the mutual influence of two ligands bound to the same metal ion. Zinc(II), among other transition metal ions, plays a vital role in biological processes. Zinc deficiency can cause unusual disorders in the development of the body, disorders in the metabolic system and prostate gland,
Li-Juan Luo,Jian-Quan Weng
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811044114
Abstract: The complete molecule of the title compound, C26H38N2, is generated by a crystallographic inversion centre. The piperazine ring adopts a chair conformation with pseudo-equatorial substituents. In the crystal, molecules interact only by van der Waals forces.
1,4-Bis(carboxymethyl)piperazine-1,4-diium bis(dihydrogen phosphate) dihydrate  [cached]
Lin Cheng,Li-Min Zhang,Jian-Quan Wang
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810036342
Abstract: In the title salt, C8H16N2O42+·2H2PO4 ·2H2O, the piperazine ring is located around an inversion center and adopts a chair conformation. The dihydrogen phosphate anions and free water molecules are linked via O—H...O hydrogen bonds into two-dimensional hydrogen-bonding layers, which are further connected through O—H...O and N—H...O hydrogen bonds involving the protonated piperazine into a three-dimensional supramolecular network.
Yongjun Liu,Xuefeng Sun,Yonghong Wen
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812026372
Abstract: The asymmetric unit of the title compound, C18H18N2O2, consists of two independent molecules, each of which is located about a center of inversion. The molecules are not planar, showing dihedral angles of 55.84 (9) and 54.10 (8)° between the piperazinedione and the aromatic rings. The piperazine N atoms exhibit a planar configuration. The crystal packing is stabilized by intermolecular C—H...O hydrogen bonds.
tert-Butyl 4-{[5-(4-chlorophenyl)-1-(4-fluorophenyl)-1H-pyrazol-3-yl]carbonyl}piperazine-1-carboxylate  [cached]
R. Venkat Ragavan,V. Vijayakumar,S. Sarveswari,Seik Weng Ng
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810038560
Abstract: In the title pyrazole derivative, C25H26ClFN4O3, both benzene rings are twisted out of the plane through the pyrazole ring, with dihedral angles of 67.62 (10) and 27.63 (10)° for the fluoro- and chloro-substituted rings, respectively. The dihedral angle between the two benzene rings is 64.54 (9)°. The piperazine ring (with a chair conformation) is linked to the pyrazole ring via a carbonyl spacer and is orientated to lie to one side of the pyrazole plane. In addition to an intramolecular C—H...N contact, there are intermolecular C—H...O interactions, which generate a supramolecular chain with an undulating topology along the c axis that is sustained by alternating centrosymmetric ten-membered {...HCNCO}2 and {...HC3O}2 synthons.
A preliminary note on the use of Quiloflex (Benzodioxane Hydro- chloride) in the immobilization of game
B.V.Sc., J. W. Van Niekerk,Ph.D., U. De V. Pienaar,B.Sc. (Agric.), N Fairall
Koedoe : African Protected Area Conservation and Science , 1963, DOI: 10.4102/koedoe.v6i1.817
Abstract: A preliminary note on the use of Quiloflex (Benzodioxane Hydro-chloride) in the immobilization of game
Tomar Amita,Mall Mridula,Verma Manju
International Journal of Research in Ayurveda and Pharmacy , 2011,
Abstract: Piperazine nucleus is one of the most important heterocyclic exhibiting remarkable pharmacological activities. The present review provides a broad view of the pharmacological activities, antipsychotic, anticonvulsants, antiarrhythmic, antimicrobial, antioxidant, antimalarial, and cytotoxic activities possessed by compounds having piperazine nucleus.
Determination of Carbonyl Group Content in Plasma Proteins as a Useful Marker to Assess Impairment in Antioxidant Defense in Patients with Eales′ Disease  [cached]
Rajesh Mohanraj,Sulochana Konerirajapuram,Coral Karunakaran,Punitham Ranganathan
Indian Journal of Ophthalmology , 2004,
Abstract: Purpose: Formation of protein carbonyl groups is considered an early biomarker for the oxidant/antioxidant barrier impairment in various inflammatory diseases. We evaluated the intensity of free radical reactions in patients with Eales′ disease, an idiopathic inflammatory condition of the retina. Methods: Twenty patients with Eales′ disease in active vasculitis stage, 15 patients with Eales′ disease in healed vasculitis stage and 20 healthy control subjects were recruited for the study. Plasma protein carbonyl groups,plasma glutathione (GSH) superoxide dismutase (SOD) activity and thiobarbituric acid reactive substances (TBARS) were determined in erythrocytes. Results: Plasma protein carbonyl content was elevated by a factor of 3.5 and 1.8 respectively in active and healed vasculitis stages. The increase of carbonyl group content in active and healed stage of patients with Eales′ disease correlated with diminished SOD activity and GSH content. There was also increased accumulation of TBARS in active and healed vasculitis stages of Eales′ disease, and this correlated with diminished SOD activity. Conclusion: Our results showed that protein carbonyl group content increases with severity of Eales′ disease. The increase in carbonyl content correlated with diminished antioxidant status. This confirms an earlier report that free radical mediated tissue damage occurs in Eales′ disease. The determination of protein carbonyl content may be used as a simple biomarker to monitor the efficacy of antioxidant supplementation in controlling retinal vasculitis in patients with Eales′ disease.
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.