Synthesis, Quantum Chemical Calculations, Molecular Docking and Studying the Effect of High Energetic Gamma Irradiation on Cu(I, II), Zn(II) and Cd(II) Complexes with their Antibacterial Activity.

Author(s):  
Hussein Elganzory

Abstract New complexes of Cu(I,II), Zn(II) and Cd(II) of thiosemicarbazide ligand 1-(p-(methylanilinocetyl-4-phenyl-thiosemicarbazide)(H2LB) have been prepared and characterized by 1HNMR, Mass spectra, FT-IR, elemental analyses, molar conductance, UV-visible spectra, magnetic susceptibility measurements, thermogravimetric analysis (TGA/DTG) and X-ray diffraction pattern before and after irradiation. The results confirmed that gamma ray enhanced the stability of irradiated compounds as compared to non-irradiated compounds. XRD patterns proved that increasing the crystallinity of the samples and the particles in nano range after gamma irradiation. The obtained data indicated that the Cu(I) and Cd(II) ions coordinated to the ligand through the (C = O), N(2)H and (C = S), the ligand behaves as neutral tridentate. While in complexes Cu(II) and Zn(II)complexes (B2 and B3) the ligand behave as neutral tetradentate and coordination take place via (C = O) and two N(2)H. These studies revealed that, two kinds of stereochemical geometries; Cu(II) and Zn(II) complexes were predicted to be octahedral, Cu(I) and Cd(II)complexes were found to be tetrahedral. The theoretical conformational structure analyses were performed using density functional theory for ligand and complexes at B3LYP functional with 6-31G(++)d,p basis set for ligand and LANL2DZ basis set for complexes. The ligand and its metal complexes have been tested for their inhibitory effect on the growth of bacteria against gram-positive (Streptococcus pyogenes) and gram-negative (Escherichia coli). Results suggested that in case of 1µg/ml and 5µg/ml for Cu(II) and Zn(II) complexes have higher activity than other complexes. The chelation could facilitate the ability to cross the cell membrane of E. coli and can be explained by Tweedy’s chelation theory. Molecular docking investigation proved that; the Zn(II) complex had interesting interactions with active site amino acids of topoisomerase II DNA gyrase enzymes (code: 2XCT).

2021 ◽  
Author(s):  
Hussein Elganzory

Abstract Novel complexes of Cu(I,II), Zn(II) and Cd(II) of thiosemicarbazide ligand (H2LB) have been prepared and characterized. The results confirmed that gamma ray enhanced the stability of irradiated compounds as compared to non-irradiated . XRD patterns proved that increasing the crystallinity of particles in nano range after gamma irradiation. Data obtained indicated that the Cu(I) and Cd(II) ions coordinated to the ligand through the (C=O), N(2)H and (C=S), (neutral tridentate ligand). While, Cu(II) and Zn(II) complexes the ligand behaves as neutral tetradentate and coordination take place via (C=O) and two N(2)H . These studies revealed that, two kinds of stereochemical geometries; Cu(II) and Zn(II) complexes were predicted to be octahedral, Cu(I) and Cd(II) complexes were found to be tetrahedral. The theoretical conformational structure analyses were performed using DFT at B3LYP functional with 6‐31G(++)d,p basis set for ligand and LANL2DZ basis set for complexes. The inhibitory effect on the growth against gram-positive and gram-negative bacteria of prepared complexes have been tested. Results suggested that 1μg/ml and 5µg/ml for Cu(II) and Zn(II) complexes have higher activity than other complexes. The chelation could facilitate the ability to cross the cell membrane of E. coli. Molecular docking investigation proved that; the Zn(II) complex has interesting interactions with active site amino acids of topoisomerase II DNA gyrase enzymes (code: 2XCT).


Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3631
Author(s):  
Ahmed M. Deghady ◽  
Rageh K. Hussein ◽  
Abdulrahman G. Alhamzani ◽  
Abeer Mera

The present investigation informs a descriptive study of 1-(4-Hydroxyphenyl) -3-phenylprop-2-en-1-one compound, by using density functional theory at B3LYP method with 6-311G** basis set. The oxygen atoms and π-system revealed a high chemical reactivity for the title compound as electron donor spots and active sites for an electrophilic attack. Quantum chemical parameters such as hardness (η), softness (S), electronegativity (χ), and electrophilicity (ω) were yielded as descriptors for the molecule’s chemical behavior. The optimized molecular structure was obtained, and the experimental data were matched with geometrical analysis values describing the molecule’s stable structure. The computed FT-IR and Raman vibrational frequencies were in good agreement with those observed experimentally. In a molecular docking study, the inhibitory potential of the studied molecule was evaluated against the penicillin-binding proteins of Staphylococcus aureus bacteria. The carbonyl group in the molecule was shown to play a significant role in antibacterial activity, four bonds were formed by the carbonyl group with the key protein of the bacteria (three favorable hydrogen bonds plus one van der Waals bond) out of six interactions. The strong antibacterial activity was also indicated by the calculated high binding energy (−7.40 kcal/mol).


2020 ◽  
Vol 3 (4) ◽  
pp. 989-1000
Author(s):  
Mustapha Abdullahi ◽  
Shola Elijah Adeniji

AbstractMolecular docking simulation of thirty-five (35) molecules of N-(2-phenoxy)ethyl imidazo[1,2-a]pyridine-3-carboxamide (IPA) with Mycobacterium tuberculosis target (DNA gyrase) was carried out so as to evaluate their theoretical binding affinities. The chemical structure of the molecules was accurately drawn using ChemDraw Ultra software, then optimized at density functional theory (DFT) using Becke’s three-parameter Lee–Yang–Parr hybrid functional (B3LYP/6-311**) basis set in a vacuum of Spartan 14 software. Subsequently, the docking operation was carried out using PyRx virtual screening software. Molecule 35 (M35) with the highest binding affinity of − 7.2 kcal/mol was selected as the lead molecule for structural modification which led to the development of four (4) newly hypothetical molecules D1, D2, D3 and D4. In addition, the D4 molecule with the highest binding affinity value of − 9.4 kcal/mol formed more H-bond interactions signifying better orientation of the ligand in the binding site compared to M35 and isoniazid standard drug. In-silico ADME and drug-likeness prediction of the molecules showed good pharmacokinetic properties having high gastrointestinal absorption, orally bioavailable, and less toxic. The outcome of the present research strengthens the relevance of these compounds as promising lead candidates for the treatment of multidrug-resistant tuberculosis which could help the medicinal chemists and pharmaceutical professionals in further designing and synthesis of more potent drug candidates. Moreover, the research also encouraged the in vivo and in vitro evaluation study for the proposed designed compounds to validate the computational findings.


Author(s):  
Satyendra Shukla ◽  
Pratiksha Gaur ◽  
Sanjay Bagri ◽  
Ripul Mehrotra ◽  
Bhaskar Chaurasia

Tailored reaction of Schiff base ligands with palladium(II) chloride and imidazole afford three complexes of formula [Pd(II)(L)(imdz)2]Cl; where L = 2-((E)-(p-lylimino)methyl)-6-methoxyphenol (complex 1); 2-methoxy-6- -((E)-(phenylimine)methyl)phenol (complex 2); and 2-((E)-(4-chlorophenyl-imino)methyl)-6-methoxyphenol (complex 3). Compounds were characterized with elemental analysis, molar conductance, electronic spectroscopy, ESI-MS, FT-IR, TGA, 1H-NMR and 13C-NMR. Molecular structure and different quan-tum chemical parameters were calculated using the B3LYP basis set of density functional theory with the standard 6-311+G (d, 2p) level. The catalytic potential of 1-3 was examined over Heck-Mizoroki reaction and found in order of 1 > 2 > 3.


2021 ◽  
Vol 11 (6) ◽  
pp. 13806-13828

The development of novel and safe compounds is a challenging task in the drug discovery trajectory. Accordingly, the individuation of promising core molecules with biological activities could pave the way to develop effective drugs to treat a given disease. The use of a computational approach can reduce the time for identifying promising core molecules characterizing their potential pharmacological profile and providing hints for the synthesis of novel derivatives with increased predicted pharmacological activity. Following this strategy, starting from a core molecule thiazolidine-2,4-dione, the derivative of 5-(3-nitro-arylidene)-thiazolidine-2,4-dione was synthesized to investigate the biological and pharmacological potential. An extensive computational investigation was performed employing ab initio calculations by using Density Functional Theory (DFT), and subsequent in silico studies were accomplished by molecular docking calculation. The structures 5-(3-nitro-arylidene)-thiazolidine-2,4-dione were fully optimized using multiparametric DFT methods were calculated at the B3LYP/6-31+G (d, p) level basis set. Besides gaining insights into the potential pharmacological profile of the selected derivative, molecular docking against some selected drug targets, ADME, and PASS prediction were performed. According to charges and molecular electrostatic potential (MESP) calculation, the N-H region could offer promising active site interactions for protein binding. Furthermore, Homo-Lumo and global reactivity values indicate a good profile for the selected compound, and UV-Vis provides further insights about its properties, potentially helpful for further experimental analysis. Notably, the in silico investigation indicated that EGFR and ORF2 enzymes could represent the selected drug-like compound's possible targets. Conclusively, the proposed computational approach demonstrated that it is possible to evaluate a proposed compound's bioactivity profile. We characterized 5-(3-nitro-arylidene)-thiazolidine-2,4-dione derivative, suggesting it as a good starting point for developing interesting hit compounds with a relevant pharmacological profile.


2021 ◽  
Vol 6 (3) ◽  
pp. 186-203
Author(s):  
Meenakshi Singh ◽  
Mukesh Kumar ◽  
Neha Singh ◽  
Shikha Sharma ◽  
Neha Agarwal ◽  
...  

In this work, the quantum computations of newly synthesized N-(4-hydroxyphenyl)picolinamide (4-HPP) is focused. Density functional theory (DFT) was used to perform the quantum calculations. The optimized molecular geometry was obtained using the B3LYP and MP2 methods employing 6-311++G(d,p) basis set, which served as the foundation for all subsequent calculations. The experimental data was compared with the calculated vibrational frequencies and NMR spectra. With the use of the molecular electrostatic potential surface (MEP) and the Fukui functions, the charge distribution, reactive regions and electrostatic potential were displayed. The chemical activity of the 4-HPP was evaluated by the energy difference between HOMO and LUMO. For better understanding of the intermolecular charge transfer (ICT), natural bond order analysis (NBO) was used. At various temperatures, thermodynamic parameters such as Gibb’s free energy, enthalpy and entropy were determined. The electrophilicity index was used to portray the molecule’s bioactivity and molecular docking was used to show the interaction between the ligand and the protein. The nature of the molecule was determined by drug similarity when expecting its application for medical purposes.


2020 ◽  
Vol 21 (4) ◽  
pp. 1253 ◽  
Author(s):  
Mohamed E. Elshakre ◽  
Mahmoud A. Noamaan ◽  
Hussein Moustafa ◽  
Haider Butt

In this work, three computational methods (Hatree-Fock (HF), Møller–Plesset 2 (MP2), and Density Functional Theory (DFT)) using a variety of basis sets are used to determine the atomic and molecular properties of dihydrothiouracil-based indenopyridopyrimidine (TUDHIPP) derivatives. Reactivity descriptors of this system, including chemical potential (µ), chemical hardness (η), electrophilicity (ω), condensed Fukui function and dual descriptors are calculated at B3LYP/6-311++ G (d,p) to identify reactivity changes of these molecules in both gas and aqueous phases. We determined the molecular electrostatic surface potential (MESP) to determine the most active site in these molecules. Molecular docking study of TUDHIPP with topoisomerase II α and β is performed, predicting binding sites and binding energies with amino acids of both proteins. Docking studies of TUDHIPP versus etoposide suggest their potential as antitumor candidates. We have applied Lipinski, Veber’s rules and analysis of the Golden triangle and structure activity/property relationship for a series of TUDHIPP derivatives indicate that the proposed compounds exhibit good oral bioavailability. The comparison of the drug likeness descriptors of TUDHIPP with those of etoposide, which is known to be an antitumor drug, indicates that TUDHIPP can be considered as an antitumor drug. The overall study indicates that TUDHIPP has comparable and even better descriptors than etoposide proposing that it can be as effective antitumor drug, especially 2H, 6H and 7H compounds.


2021 ◽  
Vol 11 (9) ◽  
pp. 4067
Author(s):  
Linda-Lucila Landeros-Martínez ◽  
Néstor Gutiérrez-Méndez ◽  
Juan Pedro Palomares-Báez ◽  
Nora-Aydeé Sánchez-Bojorge ◽  
Juan Pablo Flores-De los Ríos ◽  
...  

Type 2 diabetes mellitus has been classified as the epidemic of the XXI century, making it a global health challenge. Currently, the commonly used treatment for this disease is acarbose, however, the high cost of this medicine has motivated the search for new alternatives. In this work, the maysin, a characteristic flavonoid from maize inflorescences, and its aglycon version, luteolin, are proposed as acarbose substitutes. For this, a theoretical comparative analysis was conducted on the molecular interactions of acarbose, maysin, and luteolin with human maltase-glucoamylase (NtMGAM), as well as their oxidative process. The binding energies in the active site of NtMGAM with acarbose, maysin, and luteolin molecules were predicted using a molecular docking approach applying the Lamarckian genetic algorithm method. Theoretical chemical reactivity parameters such as chemical hardness (η) and chemical potential (µ) of the acarbose, maysin, and luteolin molecules, as well as of the amino acids involved in the active site, were calculated using the electronic structure method called Density Functional Theory (DFT), employing the M06 meta-GGA functional in combination with the 6-31G(d) basis set. Furthermore, a possible oxidative process has been proposed from quantum-chemical calculations of the electronic charge transfer values (ΔN), between the amino acids of the active site and the acarbose, maysin, and luteolin. Molecular docking predictions were complemented with molecular dynamics simulations. Hence, it was demonstrated that the solvation of the protein affects the affinity order between NtMGAM and ligands.


Author(s):  
Haitham AlRabiah ◽  
S Muthu ◽  
Fatmah Al-Omary ◽  
Abdul-Malek Al-Tamimi ◽  
M Raja ◽  
...  

Theoretical and experimental FT-IR and FT-Raman vibrational spectral analysis of 6-[(2-methylphenyl)sulfanyl]-5-propylpyrimidine-2,4(1H,3H)-dione have been recorded in the region 4000-400 cm-1 and 4000-100 cm-1 insolid phase. The molecular geometrical parameters, bond length, bond angle and vibrational wave numbers, harmonic vibrational frequency were investigated using the density functional theory B3LYP method with the 6-311++G(d,p) basis set. The stability of the molecule has been investigated using the natural bond orbital (NBO) analysis. The electronic properties such as HOMO-LUMO energies were determined by the time-dependent DFT approach. The thermodynamical properties and the first order hyperpolarizability and molecular electrostatic potential (MEP) of the title compound were also studied. The electron density-based local reactivity descriptors such as the Fukui functions were calculated to explain the chemical selectivity or reactivity site in the molecule. The molecule orbital contributions were investigated using the total density of states (TDOS), the sum of 𝛼 and 𝛽 electron density of states (𝛼𝛽DOS). The molecular docking (ligand-protein) simulations have been performed using the SWISSDOCK server. The full fitness (FF) score and hydrogen bonding interaction and binding affinity values revealed that title compound can act as potential inhibitor against HIV-1 protease.


Author(s):  
Samuel Ndaghiya Adawara ◽  
Gideon Adamu Shallangwa ◽  
Paul Andrew Mamza ◽  
Abdulkadir Ibrahim

Abstract Background Dengue fever is a key public health unease in various tropical and sub-tropical regions. The improvement of existing agents that can inhibit the dengue virus is therefore of utmost importance. In this work, the QSAR study was carried out on 25 molecules of phthalazinone derivatives which have been reported to possess excellent dengue virus inhibitory activity. Density functional computational technique was used in the optimisation of the molecules with the basis set at theory level (B3LYP, 6-31G*) respectively. The multiple linear regression (MLR) model was built using genetic function approximation (GFA) in the material studio software package. Also, in this study, molecular docking simulation was carried between dengue virus serotype 2 protease (PDB CODE: 6mol) and some selected phthalazinone derivatives (compounds 1, 2, 7, 11, and 21). Results The model was robust as evidenced by validation and robustness statistical parameter which include predicted R2pred., adjusted R2adj., cross-validated Q2 and R2 regression coefficient, etc (R2pred. = 0.71922, R2adj. = 0.939699, Q2CV = 0.905909, R2 = 0.955567) respectively. The molecular docking studies conducted in this study have outlined the binding affinities of the selected compounds (1, 2, 7 11, and 21) which are all in good correlation with their respective pIC50 values. The free binding affinities of the selected compounds were found to be (− 8.7, − 8.8, − 8.7, − 8.3, and − 8.9 kcal/mol) respectively, compound 21 with the binding affinity of − 8.9 kcal/mol had the best binding free energy with the protease relative to other compounds under consideration. Conclusion The MLR-GFA model study alongside with the molecular docking analysis has essentially provided a valuable and in-depth understanding as well as knowledge for the development of novel chemical compounds with enhanced inhibitory potential against the dengue virus serotype 2 (DNV-2). Hence, the developed model can be applicable in predicting the anti-dengue activity of a new set of chemical compounds that fall within its applicability domain.


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