Computer-aided approaches reveal trihydroxychroman and pyrazolone derivatives as potential inhibitors of SARS-CoV-2 virus main protease

COVID-19 was declared a pandemic by the World Health Organization (WHO) in March 2020. The disease is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The aim of this study is to target the SARS-CoV-2 virus main protease (Mpro) via structure-based virtual screening. Consequently, > 580,000 ligands were processed via several filtration and docking steps, then the top 21 compounds were analysed extensively via MM-GBSA scoring and molecular dynamic simulations. Interestingly, the top compounds showed favorable binding energies and binding patterns to the protease enzyme, forming interactions with several key residues. Trihydroxychroman and pyrazolone derivatives, SN02 and SN18 ligands, exhibited very promising binding modes along with the best MM-GBSA scoring of –40.9 and –41.2 kcal mol–1, resp. Hence, MD simulations for the ligand-protein complexes of SN02 and SN18 affirmed the previously attained results of the potential inhibition activity of these two ligands. These potential inhibitors can be the starting point for further studies to pave way for the discovery of new antiviral drugs for SARS-CoV-2

Computer-aided discovery of antimicrobial agents as potential enoyl acyl carrier protein reductase inhibitors

Purpose: To perform a virtual screening for a set of drug-like ligand library against the Staphylococcus aureus enoyl acyl carrier protein reductase, saFabI.Methods: The virtual screening was conducted based on a previously validated pharmacophoreconstrained docking. Consequently, the top list obtained was filtered using visual inspection where forty compounds were selected for experimental testing using disk-diffusion test and broth dilution method. The hits obtained were checked for their toxicity against human fibroblasts cell lines.Results: Three compounds were active against Staphylococcus aureus and other tested gram-positive bacteria. However, no significant inhibitory activity (p < 0.05) was detected against Escherichia coli or Candida albicans. The minimum inhibitory concentration (MIC) values for the most active compounds were identified using the broth dilution method; all of them exhibited inhibitory activity within micromolar range.The docking results showed that the hits obtained exhibited a small size with a nice binding mode to saFabI enzyme, forming the important interactions with the key residues. Furthermore, the best three hits demonstrated good safety profile as they did not show any significant toxicity against human fibroblast cell line.Conclusion: Overall, the newly discovered hits can act as a good starting point in the future for the development of safe and potent antibacterial agents.Keywords: Enoyl acyl carrier protein reductase, saFabI, Antibacterial agents, Docking, Constraint, Virtual screening Tropical Journal of Pharmaceutica

SYNTHESIS OF AMINO ACETYLENIC BENZOPHENONE DERIVATIVES AS H3-ANTAGONISTS

Objective: To synthesize new amino acetylenic benzophenone derivatives with significant H3-antagonist's activity.Methods: Amino acetylenic benzophenone derivatives were synthesized from the reaction of 2-hydroxybenzophenone with 3-bromoprop-1-in to generate 2-(prop-2-yn-1-yloxy)-1,3-benzophenone (AZ-1). A mixture of 2-(prop-2-yn-1-yloxy)-1,3-benzophenone, paraformaldehyde, cyclic amine, cuprous chloride (catalytic amount) in peroxide free dioane through Mannich reaction yielded the designed amino acetylenic benzophenone derivatives (AZ-2-7).Results: The IR, H1-NMR, 13C NMR, and elemental analysis were consistent with the assigned structures. The designers of these compounds as H3-antagonists were based on the nationalization of the important criteria that provide effective inhibitory binding with H3-receptor. Molecular docking results of compounds (AZ-2-7) showed a good H3-receptor antagonistic activity relative to thioperamide of-6 (kcal/mol) especially AZ-2 which has-8.6 (kcal/mol).Conclusion: Docking results provide a good lead to designing more effective H3 antagonists in managing many CNS diseases like Alzheimer, epilepsy, depression, schizophrenia and many others

DESIGN, SYNTHESIS AND BIOLOGICAL SCREENING OF AMINOACETYLENIC TETRAHYDROPHTHALIMIDE ANALOGUES AS NOVEL CYCLOOXYGENASE (COX) INHIBITORS

Objective: To design and synthesise a new amino acetylenic tetrahydro phthalimide derivative and investigate their selective inhibitory activity to COXs.Methods: Aminoacetylenic tetrahydro phthalimide derivatives were synthesised by alkylation of tetrahydro phthalimide with propargyl bromide afforded 2-(prop-2-yn-1-yl)-2,3,3a,4,7,7a-hexahydro-1H-isoindole-1,3-dione. The alkylated tetrahydro phthalimide was subjected to Mannich reaction afforded the desired amino acetylenic tetra phthalimide derivatives (AZ 1-6). The elemental analysis was indicated by the EuroEA elemental analyzer and biological characterization was via IR, 1H-NMR, [13]C-NMR, DSC was determined with the aid of Bruker FT-IR and Varian 300 MHz spectrometer and DMSO-d6 as a solvent, molecular docking was done using the Autodock Tool software (version 4.2). ChemBioDraw was used in the drawing of our schemes.Results: The IR, 1H-NMR, 13C-NMR, DSC and elemental analysis were consistent with the assigned structures. The designers of the compounds as COXs inhibitor activity were based on the nationalisation of the important criteria that provide effective inhibitory binding with COXs–receptor. The results indicated that the synthesised compounds (AZ1-6) showed a close similarity in the binding affinity to both COXs and may be more specific to COX-1. AZ-5 showed the highest % of inhibition for COX-1 even better than aspirin. Which may suggest that the aryl group is required for COX-2 inhibition.Conclusion: For the first time, we indicate the requirement of aromaticity in COX-2 structural inhibitory activity.Â

Support for UNRWA's survival

The United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) provides life-saving humanitarian aid for 5·4 million Palestine refugees now entering their eighth decade of statelessness and conflict. About a third of Palestine refugees still live in 58 recognised camps. UNRWA operates 702 schools and 144 health centres, some of which are affected by the ongoing humanitarian disasters in Syria and the Gaza Strip. It has dramatically reduced the prevalence of infectious diseases, mortality, and illiteracy. Its social services include rebuilding infrastructure and homes that have been destroyed by conflict and providing cash assistance and micro-finance loans for Palestinians whose rights are curtailed and who are denied the right of return to their homeland

GW-2974 and SCH-442416 modulators of tyrosine kinase and adenosine receptors can also stabilize human telomeric G-quadruplex DNA

GW-2974 is a potent tyrosine kinase receptor inhibitor while SCH-442416 is a potent adenosine receptors’ antagonist with high selectivity towards human adenosine A2A receptor over other adenosine receptors. The two compounds were reported to possess anti-cancer properties. This study aimed to investigate whether stabilization of human telomeric G-quadruplex DNA by GW-2974- and SCH-442416 is a plausible fundamental mechanism underlying their anti-cancer effects. Human telomeric G-quadruplex DNA with sequence AG3(TTAGGG)3 was used. The study used ultraviolet-visible (UV-Vis), fluorescence, fluorescence quenching, circular dichroism (CD), melting temperatures (Tm) and molecular docking techniques to evaluate interactions. The results showed that GW-2974 and SCH-442416 interacted with G-quadruplex DNA through intercalation binding into two types of dependent binding sites. Binding affinities of 1.3 × 108–1.72 × 106 M−1 and 1.55 × 107–3.74 × 105 M−1 were obtained for GW-2974 and SCH-442416, respectively. An average number of binding sites between 1 and 2 was obtained. Additionally, the melting temperature curves indicated that complexation of both compounds to G-quadruplex DNA provided more stability (ΔTm = 9.9°C and 9.6°C, respectively) compared to non-complexed G-quadruplex DNA. Increasing the molar ratios over 1:1 (drug:G-quadruplex) showed less stabilization effect on DNA. Furthermore, GW-2974 and SCH-442516 have proven ≥ 4.0 folds better selective towards G-quadruplex over double-stranded ct-DNA. In silico molecular docking and dynamics revealed favorable exothermic binding for the two compounds into two sites of parallel and hybrid G-quadruplex DNA structures. The results supported the hypothesis that GW-2974 and SCH-442416 firmly stabilize human telomeric G-quadruplex DNA in additions to modulating tyrosine kinase and adenosine receptors. Consequently, stabilizing G-quadruplex DNA could be a mechanism underlying their anti-cancer activity