The structural and corrosion inhibition properties of four different transition-metal complexes of heteroleptic S-donor atom dithiophosphonate and N-donor atom phenanthroline ligands are reported.

COVID-19 pandemic has poses urgent health challenge, and this project aims to identify potential inhibitors to combat this virus. We screened 198 bioactive compounds from five selected medicinal plants previously reported to be antiviral against SARS-CoV-2 protease and two co-receptors followed by molecular dynamics simulations. From the screened compounds, Astragalin demonstrated very strong molecular interactions with the molecular docking binding energies −8.5, −8.0, −7.6 kcal/mol for 6LU7, 6LZG, and 6VXX proteins of SARS-CoV-2, respectively. Hydrogen bonding interaction with the active site catalytic residue HIS-41 or CYS-145 of the main protease SARS-CoV-2 was observed. Binding free energies (ΔG_bind) from MM-GBSA after 50 ns MD simulations showed that Astragalin has the highest energy of −33.00 and −34.89 kcal/mol in complex with the main protease and spike glycoprotein of SARS-CoV-2, respectively. The study identifies Astragalin as a better inhibitor for the inactivation of COVID-19 and should be pursued as a potential drug candidate for this virus.

Three Schiff bases 1-(4-chlorophenyl)-N-(naphthalen-1-yl)methanimine (1), 1-(4-methoxy phenyl)-N-(naphthalen-1-yl)methanimine (2), and 1-(4-chlorophenyl)-N-(2,6-diisopropyl phenyl)methanimine (3) were synthesized and characterized by elemental analysis, 1H and 13C NMR, FT-IR and UV-Visible spectroscopic techniques. The crystal structure of compound 3 was obtained and it revealed that the compound crystallized in a monoclinic space group P21/n and there exists an intermolecular hydrogen bond in a phenyl-imine form with C-H⋯N. Crystal data for C19H22ClN: a = 7.28280(10) Å, b = 9.94270(10) Å, c = 24.0413(2) Å, β = 97.0120(10)°, V = 1727.83(3) Å3, Z = 4, μ(Mo Kα) = 0.215 mm-1, Dcalc = 1.1526 g/cm3, 14038 reflections measured (12.42° ≤ 2Θ ≤ 52.74°), 3448 unique (Rint = 0.0223, Rsigma = 0.0182) which were used in all calculations. The final R1 was 0.0337 (I≥2u(I)) and wR2 was 0.0927 (all data). The free radical scavenging activities of all three compounds were assayed using DPPH, FRAP, and OH assays. According to results obtained, compound 2 shows effective DPPH- (IC50 = 22.69±0.14 μg/mL), FRAP+ (IC50 = 28.44±0.12 μg/mL), and OH- (IC50 = 27.97±0.16 μg/mL) scavenging activities compared with compounds 1 and 3 but less than standard antioxidant compound Trolox (TRO). Additionally, theoretical calculations for the three complexes were performed by using density functional theory (DFT) calculations at the B3LYP/6-31++G(2d,2p) level in the ground state to obtain an optimized geometrical structure and to perform an electronic, molecular electronic potential surface and natural bond orbital (NBO) analysis. The geometrical calculation obtained was found to be consistent with the experimental geometry. Further analysis was conducted using the in silico technique to predict the drug likeness, molecular and ADME properties of these molecules.

Several natural products have been of help to humans, and its effect is noticeable in the medicinal world. Soursop with botanical name Annona muricata L. possesses antidiarrhea, anticold fever, antirheumatism, and antineuralgia properties. In this work, five selected molecular compounds were studied against type 3 of 3α-hydroxysteroid dehydrogenase (3α-HSD). Its anticancer activity was investigated using the quantum chemical method via Spartan 14 software, molecular docking via Discovery studio 2017, AutoDock Tool 1.5.6, AutoDock Vina 1.1.2, and PyMol 1.7.4.4 and the molecular dynamic simulation method via AMBER14 molecular dynamics package. Many descriptors (E_HOMO, E_LUMO, dipole moment, energy bandgap, area, volume, polarizability, polar surface area, Log P, hydrogen bond donor, and hydrogen bond acceptor) which describe the anticancer activity of the studied compounds were obtained. Also, the docking study revealed the inhibiting ability of the studied compound, and it was observed that compound C possesses a greater ability to inhibit than other studied compounds as well as the standard (5FU).

Peptidoglycan, the exoskeleton of bacterial cell and an essential barrier that protects the cell, is synthesized by a pathway where the final steps are catalysed by transpeptidases. Knowledge of the structure and function of these vital enzymes that generate this macromolecule in M. tuberculosis could facilitate the development of potent lead compounds against tuberculosis. This review summarizes the experimental and computational studies to date on these aspects of transpeptidases in M. tuberculosis that have been identified and validated. The reported structures of L,D- and D,D-transpeptidases, as well as their functionalities, are reviewed and the proposed enzymatic mechanisms for L,D-transpeptidases are summarized. In addition, we provide bioactivities of known tuberculosis drugs against these enzymes based on both experimental and computational approaches. Advancing knowledge about these prominent targets supports the development of new drugs with novel inhibition mechanisms overcoming the current need for new drugs against tuberculosis.