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The recent outbreak of COVID-19 (Coronavirus Disease 2019), caused by a novel SARS-CoV-2 virus, has led to public health emergencies worldwide where time is as important as equipment to save lives. Antimalarial drugs such as hydroxychloroquine and chloroquine derivatives are used in emergencies but they are not suitable for patients with high blood pressure, diabetes and heart problems. Since there are no approved drugs for this disease, science is challenged to find vaccines and new drugs. Therefore, as part of our Silico drug design strategy, we identified drug-like compounds that inhibit replication of the main protease (Mpro) of SARS-CoV-2 based on receptor-based virtual database screening, molecular docking, molecular dynamics, and drug-similarity profiling from the NANPDB natural products database available at North African. The two resulting hit compounds named 5- Chloro-Omega-hydroxy-1-O-methylemodin and cystodion E showed the highest binding energy with Mpro of SARS-CoV-2 and strong inhibitory activity compared with the previously published N3 inhibitor. The complexes of these two compounds were validated by molecular dynamics analysis (RMSD, RMSF, Rg, total number of hydrogen bonds and secondary structure fractions of the protein in the complex) as the best method to evaluate the biological stability of the system. Therefore, these molecules deserve more attention in drug development compared to COVID-19. HighlightsA large database of natural compounds was screened against nCoV-2's Mpro.Molecular docking and Molecular dynamics were used as powerful methods.Two compounds were found are very attractive to inhibit Mpro of nCoV-2.ADME-Tox profiling is evaluated the active compounds are not cancerogenic.Communicated by Ramaswamy H. Sarma.

A database of 300 compounds was virtually screened and docked against Bcl-2 protein; the stability of the best-formed complex was evaluated through Molecular dynamics, the top ten compounds with the best in-silico complexation affinities were synthesized, and their In-vitro cytotoxic activity was examined. Thiazolidinone (4e) and isoxazoline (4a-d) were evaluated in-silico. For further evaluation and examination, we designed and synthesized from naturally occurring (R)-carvone and characterized it via spectroscopic analysis, as well as tested for their anticancer activities towards human cancer cell lines such as HT-1080 (fibrosarcome cancer), MCF-7 and MDA-MB-231 (breast cancer) and A-549 (lung cancer) by using MTT method with Doxorubicin as standard drug. Among them, compound 4d showed the most promising anticancer activity against HT-1080, A-549, MCF-7, and MDA-MB-231 cell lines with IC50 values of 15.59 ± 3.21 µM; 18.32 ± 2.73 µM; 17.28 ± 0.33 µM and 19.27 ± 2.73 µM respectively. Communicated by Ramaswamy H. Sarma

International audience; Copper removal by adsorption from an aqueous solution was tested onto the Oyster Shells (OS) powder as an inexpensive adsorbent material. The effect of process parameters such as pH, initial pollutant concentration, adsorbent mass, and contact time on the copper removal in batch experiments conditions was investigated using an experimental design methodology to determine the optimal conditions for copper treatment. Adsorbent content, initial concentration of copper, pH, and contact time for maximum Cu(II) removal (82.58 %) were optimized and were found to be 2 g, 150 mg.l−1, 5.5, and 2.5 h, respectively. The adsorption equilibrium data followed the Langmuir isotherm model, whereas the pseudo-second-order equation was the best applicable kinetic model to describe the adsorption of Copper onto OS powder. The study concluded that the OS has potential application as an adsorbent to remove toxic heavy metals such as copper from industrial wastewater. Aside from experimental methods, theoretical methods such as DFT simulations, molecular dynamics simulations, and the radial distribution method were employed to uncover parameters regulating the effectiveness of the examined adsorbate.

In this research paper, we report the cytotoxic and apoptotic effects of 1,2,3-triazole derivatives in a unique

Background: Bcl-2 family plays an essential role in the cell cycle events incorporating survival, proliferation, and differentiation in normal and neoplastic neuronal cells. Thus, it has been validated as a principal target for the treatment of cancer. For this reason, we will build a model based on a large number of Bcl-2 inhibitors to predict the activities of new compounds as future Bcl-2 inhibitors. Methods: In this study, QSAR models were successfully used to predict the inhibitory activity against Bcl-2 for a set of compounds collected from BDB (Binding database). The kPLS (kernelbased Partial Least-Square) method implemented in Schrodinger's Canvas, was used for searching the correlation between pIC50 and binary fingerprints for a set of known Bcl-2 inhibitors. Results and Discussion: Models based on binary fingerprints with two kPLS factors have been found with decent predictive power (q2 > 0.58), while the optimal number of factors is about 5. The enrichment study (148 actives, 5700 decoys) has shown excellent classification ability of our models (AUC > 0.90) for all cases). Conclusion: We found that the kPLS method, in combination with binary fingerprints, is useful for the affinity prediction and the Bcl-2 inhibitors classification. The obtained promising results, methods, and applications highlighted in this study will help us to design more selective Bcl-2 inhibitors with better structural characteristics and improved anti-cancer activity.

This study aimed to analyze the cytotoxic and apoptotic effects of isoxazoline derivatives with monoterpene scaffold

In this research work, we study the structural, optical, electronic and photovoltaic properties of eight thiophene-based π-conjugated organic molecules using quantum methods namely time-dependent density functional theory(TD-DFT). In particular, we identify the relationships between the chemical structure of these π-conjugated organic molecules and their optoelectronic properties. Moreover, we calculate and compare the highest energy occupied molecular orbital (HOMO) and lowest energy unoccupied molecular orbital (LUMO) energy levels of these compounds to that of the PCBM.As a result, the investigated molecules show a low band gap, suitable open circuit voltage and appropriate alignment energy level between the engineered donor molecules and the acceptor PCBM. This theoretical study shows that these new molecules have potential properties for the development of organic heterojunction photovoltaic cells.

Corrosion inhibition effect of aqueous polyethylene glycol (PEG) on cold-rolled steel corrosion in 1.0 M HCl solution was studied using weight loss, electrochemical potentiodynamic polarization, quantum chemical computation, molecular dynamics simulation, and scanning electron microscopy (SEM) analytical techniques. The effect of immersion time, inhibitor concentration and temperature on the corrosion behaviour of cold-rolled steel in 1.0 M HCl was studied. The results revealed that PEG satisfactorily inhibited corrosion of cold-rolled steel in the acid solution by adsorption of its molecules on the metal surface, decreasing both the anodic and cathodic reactions. Temperature studies showed that inhibition efficiency increased with rise in temperature from 303 – 343 K. Quantum chemical calculations conducted using density functional theory (DFT) showed values of EHOMO, ELUMO and energy gap for PEG to be − 7.2219 eV, − 0.3958 eV and 6.8261 eV, respectively, and thus confirmed the interaction between the PEG inhibitor molecules and the metal surface. Furthermore, the computed values of Fukui indices indicated that O(7) atom in the PEG molecule was most susceptible to nucleophilic attacks, while the O(10) atom was well disposed for electrophilic reactions. The negative values of interaction energy obtained by molecular dynamics simulation, -107.7898 kcal/mol and -109.5136 kcal/mol at 303 K and 343 K, respectively, confirmed that PEG-metal interaction was good. SEM was used to confirm the adsorption of PEG on the surface of cold-rolled steel. Based on the analyses conducted, the inhibitive mechanism for corrosion of cold-rolled steel in 1.0 M HCl solution has been established.

The adsorption of azelaic acid dihydrazide as an environmentally friendly mild steel corrosion inhibitor on the iron surface was modeled in this study. We used density functional theory (DFT) calculations and Monte Carlo (MC) and molecular dynamics (MD) simulations to illustrate the interactions engaged. The interaction of the azelaic acid derivatives with iron metal (Fe) was examined by DFT as a typical example of a corrosion prevention mechanism after the optimized molecular structures of these molecules were investigated. Structures, binding energies, Fikui’s charge indicator, electron transfer, and chemical potential are all discussed. The presence of significant binding between the inhibitor and Fe metal is supported by analysis of the resultant complex. Then, in an acidic solution comprising 491 H2O, nine chlorine ion Cl−, and nine hydronium ion H3O+, molecular dynamics and Monte Carlo (MC) simulation were used to model the adsorption of azelaic acid dihydrazide on the iron Fe (110) surface. In addition, radial distribution function (RDF) and interaction energy (Ei) were evaluated in this work to further our understanding of interactions between azelaic acid dihydrazide and iron surfaces. Furthermore, we discovered that our inhibitors have an excellent ability to slow down the movement of corrosive particles in law temperature and thus to inhibit the metallic substrate against corrosive electrolyte, based on the temperature impact investigation. The result of density functional theory and Monte Carlo and molecular dynamics descriptors obtained were in good agreement with the experimental result.

In the current study, natural (R)-carvone was utilized as a starting material for the efficient synthesis of two series of isoxazoline derivatives bearing the 1,3,4-thiadiazole moiety. The new compounds were obtained in good yields and were characterized by

In the current study, natural (R)-carvone was used as starting material for the efficient synthesis of several 1,2,3-triazole derivatives. The produced products were obtained in good yields and characterized by

The health pandemic (covid-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected, to date, over 233 million people and over 4.77 million deaths worldwide. Therefore, it is important to offer a wide understanding of the ability of potential antiviral biomolecules to combat this virus, which begins to develop new variants, potentially more transmissible and infectious. Sulphated polysaccharides (SPs) from seaweeds have been reported for their antiviral activity and their potential as vaccine adjuvants. However, their effect against SARS-CoV-2 remains very limited. In this study, seventeen ligands of SPs were screened for effective interaction with the domain (RBD) spike protein using a computational approach. The obtained results indicated that two PS ligands (Xylan sulphate and Heparin tetrasaccharide N-sulphated) effectively bind to the RBD protein and could efficiently inhibit viral entry. Overall, data support the potential importance of SPs against SARS-CoV-2 as entry inhibitors and vaccine adjuvants. Highlights Seventeen ligands of sulphated polysaccharides (SPs) were subjected to a molecular docking to assess their interaction with SARS-CoV-2 RBD spike protein;Two SP ligands showed an effective binding affinity to the RBD protein and could efficiently inhibit viral entry;One effective SP ligand (Xylan Sulphate) was predicted using ADMETox evaluation as good inhibitor;Effective candidates can have an importance against SARS-CoV-2 as entry inhibitors and vaccine adjuvants. Seventeen ligands of sulphated polysaccharides (SPs) were subjected to a molecular docking to assess their interaction with SARS-CoV-2 RBD spike protein; Two SP ligands showed an effective binding affinity to the RBD protein and could efficiently inhibit viral entry; One effective SP ligand (Xylan Sulphate) was predicted using ADMETox evaluation as good inhibitor; Effective candidates can have an importance against SARS-CoV-2 as entry inhibitors and vaccine adjuvants.

The conformational stability and internal rotation barriers, HOMO-LUMO gap and related properties, molecular static polarizability and hyperpolarizability parameters, and the NBO delocalization energies associated with the internal charge transfer (ICT) of 2.2.3-trimethylpentane in the ground state were carried out taking into account the long range dispersion correction through CAM-B3LYP and WB97XD levels at aug-cc-pvtz basis set. The six lowest conformations were differentiated by a deep and multiple spectroscopic investigation. The ultraviolet-visible (UV-Vis) absorption bands are assigned using molecular orbital data obtained by TD-WB97XD/aug-cc-pvtz calculations, and carbon 13C NMR signal peaks have been assigned using GIAO-WB97XD/aug-cc-pvtz method. In addition, the normal mode calculations of the most and less stable conformers using a scaled force field in terms of non-redundant local symmetry coordinates have been confronted to the experimental vibrational spectra temperature dependency.

In this study, the adsorption of Cytisine derivatives as an eco-friendly inhibitor for mild steel corrosion [ 1 , 2 ] on the iron surface was modeled using density functional theory (DFT) calculations and the Monte Carlo (MC) as well as Molecular dynamics (MD) simulations to elucidate the interactions involved. Firstly, the interaction of these inhibitors with iron clusters Fen (n=1-5) was studied by DFT as a representative example of a corrosion inhibition process. Moreover, structures, binding energies, partial atomic charge NBO and natural bond orbital analysis of the resulting complexes support the existence of considerable binding between these inhibitors and Fen (n=1-5) clusters. Then, the dynamic Monte Carlo (MC) simulation was also adopted to simulate the adsorption of Cytisine derivatives on the iron Fe (111) surface in vacuum as well as in acidic solution containing 491 H2O, 4 hydronium ion H3O+ and 5 chlorine ion Cl−. Besides, to advance the understanding of interactions between these molecules and iron surface, the radial distribution function (RDF), mean square displacement (MSD) and fractional free volume (FFV) were also studied in this paper. Our results of both the Fen (n=1-4) clusters and the Fe (111) surface made it possible to show noticeable competitiveness between the three protonated inhibitors with a slight superiority for the n-CytN9H+ molecule. Furthermore, based on the diffusion coefficient we found that the three protonated inhibitors have a good capacity to slow down the movement of corrosive particles and consequently to inhibit the metallic substrate against corrosive electrolyte.

A new selective synthesis of novel quinoline carboxamides was developed by the N-alkylation reaction of methyl (2-oxo-1,2- dihydroquinolin-4-yl)-L-alaninate via phase transfer catalysis in a basic medium at room temperature. The compounds were obtained in excellent yields (70-90%) and characterized by H-1, (CNMR)-C-13 spectroscopy and mass spectra. In addition, theoretical studies at B3LYP/6-311G(d,p) level were carried out to explain the observed selectivity of the N-alkylation reaction of compound 2 . The biological activities of the synthesized compounds were studied using some bacterial and fungal strains. The results show that compounds 3h and 3i exhibit stronger antibacterial activity against Bacillus subtilis and Staphyloccocus aureus. Compound 3e showed high antifungal activity against Candida Albicans compared to other substituted quinoline carboxamides. Molecular docking and molecular dynamics studies were also carried out to investigate the binding affinities of some compounds with the target proteins, and the results were in good correlation with the experimental findings. (C) 2021 Elsevier B.V. All rights reserved.

In this study, different QSAR approaches based on the multiple linear regression (MLR), the kernel-based Partial Least-Square (kPLS) and Pharma-RQSAR models have been applied to investigate the relationship between chemical structure descriptors of thiadiazole derivatives and their anticorrosion activity. The screened classical descriptors were firstly used to establish the linear regression model. In addition, six binary fingerprints were successfully applied using the kernel-based Partial Least-Square (kPLS), with priority given to the atom-pair fingerprint model. The Pharma-RQSAR model was also used to analyze the role of the various substitutions in the common substructure. The atom-pair descriptors and Pharma-RQSAR models have the advantage of visualizing the contribution maps, suggesting the general substitution requirements of the thiadiazole derivatives as potential corrosion inhibitors.

Because of their availability, lower cost, biodegradability, respect for health, environmental standards and their extremely high efficiency [Benmessaoud Left D, Zertoubi M, Irhzo A, Azzi M, Revue: Huiles et extraits de plantes comme inhibiteurs de corrosion pour différents métaux et alliages dans le milieu acide chlorhydrique, J Mater Environ Sci 4:855–866, 2013], the green corrosion inhibitors are currently the most sought after candidates. The ultimate aim of this work is to study the selectivity and reactivity of a series of three molecules, namely Cytisine, Dehydro-Cytisine and N-methyl Cytisine which are the major constituents of Retama monosperma seeds alkaloid extract (AERS) as eco-friendly inhibitors of corrosion of carbon steel in acidic medium HCl (1M), using the density functional theory (DFT) at B3LYP/aug-cc-pvdz levels. Indeed, this alkaloid extract AERS has proven experimentally its corrosion inhibitory power for carbon steel in 1 M HCl even at lower concentration (94.42% at 400[Formula: see text]mg/L). Besides, its adsorption on the steel surface in 1 M HCl solution followed Langmuir’s isotherm [El Hamdani N, Fdil R, Tourabi M, Jama C, Bentiss F, Alkaloids extract of Retama monosperma (L.) Boiss. seeds used as novel eco-friendly inhibitor for carbon steel corrosion in 1 M HCl solution: Electrochemical and surface studies, Appl Surf Sci 357:1294–1305, 2015, doi: 10.1016/j.apsusc.2015.09.159; El Hamdani N, Contribution a la valorisation des parties aériennes de Retama Monosperma, phytochimie, activités antimicrobiennes et propriétés anticorrosives, Universite Chouaib Doukkali Faculte des sciences El jadida, 2015]. Herein, the major aim of this work is to investigate the likelihood of the carbon steel corrosion being inhibited by the protonated species in the aqueous acidic solution. For this purpose, after proving that the most favorable protonation site for protonation was N9, we have evaluated the structural, global and local reactivity descriptors, partial atomic charge in terms of Natural bond orbital (NBO) of the three protonated inhibitors at the level of N9, which are the most stable in the aqueous acidic solution. NBO analysis and the thermodynamic properties such as entropy, enthalpy, heat capacity and Gibbs free energy were also done. In conclusion, it was observed that three protonated molecules showed a high propensity to adsorb to the mild steel surface with a priority of the molecule d-CytN9H+.

In this paper, we present the quantum electronic study of iso-octane, based on MP2 and B3LYP methods using the 6-311++G(d,p) basis set. In addition to conformational stability and internal rotation barriers studies, the delocalization energies associated with the internal charge transfer (ICT) within each of the six lowest energy conformers were evaluated using NBO analysis. With the aim to differentiate even more between these conformers, the energy gap between HOMO and LUMO orbitals, chemical softness, and first-order hyperpolarizability (nonlinear optics property) were evaluated. Similarly, their spectral behavior was investigated at different levels; the ultraviolet (UV) absorption bands were assigned using molecular orbitals data obtained by TD-B3LYP calculations with 6-311++G(d,p) basis set, while carbon C-13 NMR and proton H-1 signal peaks were assigned using the GIAO-B3LYP/6-311++G(d,p) method. In addition, the normal mode calculations of the most and least stable conformers using a scaled force field in terms of nonredundant local symmetry coordinates were carried out to approach the vibrational spectra temperature dependency.