Pharmacophore mapping of the crucial mediators of acetylcholinesterase and butyrylcholinesterase dual inhibition in Alzheimer's disease

Optimization and re-optimization of bioactive molecules using in silico methods have found application in the design of more active ones. Herein, we applied a pharmacophore modeling approach to screen potent dual inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) aimed at Alzheimer's disease (AD) treatment. The investigation entails molecular dynamics simulation, docking, pharmacophore modeling, drug-like screening, and binding energy analysis. We prepared a pharmacophore model from approved inhibitors of AChE and BuChE to predict the crucial moieties required for optimum molecular interaction with these proteins. The obtained pharmacophore model, used for database screening via some critical criteria, showed 229 hit molecules. Further analyses showed 42 likely dual inhibitors of AChE/BuChE with drug-like and pharmacokinetics properties the same as the approved cholinesterase inhibitors. Finally, we identified 14 dual molecules with improved potentials over the existing inhibitors and simulated ZINC92385797 bound to human AChE and BuChE structure after noticing that these 14 molecules are similar. The selected compound maintained relative stability at the active sites of both proteins over 120 ns simulation. Our integrated protocols showed the pertinent recipes of anti-AD drug design through the in silico pipeline.

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Molecular docking,ADME/Tox prediction,and in vitro study of the cell growth inhibitory activity of five β-carboline alkaloids

Structural Chemistry - In a continuing effort to find new cytotoxic, antitumor, and less toxic agents from β-carbolines derivatives, using experimental and computational studies, five...     

Reaction of sulphur dioxide with chlorocarbonyls of ruthenium,rhodium and iridium

Summary The reactions of SO₂ with chlorocarbonyls of rhodium and iridium ([M(CO)₂Cl₂]^– and ruthenium ([Ru(CO)_2–Cl₂]_n) ions were studied. Addition of either the Ph₄As⁺ cation or the nitrogen-donor ligands 2,2-bipyridine (bipy),o-phenylenediamine (opd), 1,10-phenanthroline (phen), 2,2,6,2-terpyridine (terpy) or 6,7-dihydro-1,4-di(2-pyridyl)-5H-cyclopenta {d}-pyridazine (5-dppn) to the SO_2– treated chlorocarbonyl solutions resulted in the formation of various complexes according to the nature of metal and ligand. The products have been characterized by physicochemical methods.     

RP-HPLC Method for the Quantitation of Glabridin in Yashti-madhu (Glycyrrhiza glabra)

A reverse phase high performance liquid chromatographic method is developed for the quantitation of glabridin in Glycyrrhiza glabra, using C₁₈ column with acetonitrile-water containing 2% AcOH (70:30) as an eluent. Glabridin is detected by UV absorption at 280 nm after separation by the chromatographic system. Good linearity was obtained in the working range of the concentration (0.01–0.1 mg mL^?1), with correlation coefficients 0.999. Limit of detection and limit of quantitation were 0.0195 and 0.065 mg mL^?1. The method was validated under ICH guidelines. The described method can be utilized for routine analysis (assays and stability tests) of G. glabra extracts and Ayurvedic medicine based on Yashti-madhu.     

Varying the metal/metal ratio in related Cu–Ca complexes

We demonstrate with the help of structural determinations and spectroscopic data that the nuclearity of Cu–Ca complexes derived from compartmental Schiff base ligands does not depend on the ionic radius of calcium. The main factors governing these reactions are the different affinities of the calcium ions for the anionic species present in solution: the tetradentate O₂O₂ coordination site of the ligand and the nitrato ions. Because these affinities do vary upon going from calcium to lanthanide ions, it is not possible to use the template effect of the trinuclear Cu–Ca–Cu complexes in order to prepare the corresponding Cu–Ln–Cu complexes.     

Synthesis of polyfunctionally substituted heteroaromatic compounds via benzotriazolyl chalcones with antimicrobial and antifungal activities

The utility of both 3‐(1‐benzotriazolyl) chalcone derivatives 3a‐c and 2‐(1‐benzotriazolyl)‐1,4‐pentadien‐3‐one (18) in the synthesis of some new 2‐(1H)‐pyridone, pyridine, pyrazole and isoxazole derivatives is reported. Antimicrobial and antifungal screening of some selected examples from the synthesized products were carried out. The structure of the newly synthesized compounds was elucidated by elemental analysis, ir, ¹H and ¹³C nmr investigations.     

Microwave-assisted regioselective N-alkylation of cyclic amidines

A simple and efficient methodology for regioselective alkylation of exocyclic nitrogen of cyclic amidines was developed by microwave-assisted heating in the presence of amines. Novel N-alkylated 3,4-dihydropyrazino[2,1-b]quinazolin-6-ones were prepared in good yields. The reaction occurred via a transamination (addition-elimination) process involving a first attack of the amine on the electrophilic carbon of the amidine function.     

Effect of surfactant and mineral additive on the efficiency of lead-acid battery positive active material

The effect of Sodium tripolyphosphate (STPP) and mineral additive on the performance of the lead-acid battery positive plate has been investigated. The addition of alumina-silicate to the positive paste and STPP to the electrolyte modifies the shape and size of PbO₂ crystals and improves the utilization of the positive active material (PAM). The electrochemical performance of the positive active material was determined using galvanostatic discharge and electrochemical impedance spectroscopy (EIS). The crystal structure and morphology of the PAM (PbO₂) were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The water content of the PAM was calculated using Thermogravimetric analysis (TGA) technique. The results showed that the addition of surfactant and mineral additive changes the morphology and the crystallite size of the PAM. We observe a remarkable improvement of the discharge capacity of the PAM when the surfactant (STPP) is added in the electrolyte. The discharge capacity increases with the decrease of the crystallite size and the charge transfer resistance R_ct of the PAM. This shows that the addition of mineral additive and the surfactant together improves the electrical performance of lead-acid battery.