Predicting anti-COVID-19 potential: in silico analysis of Mauritine compound from Ziziphus-spina christi as a promising papain-like protease (PLpro) inhibitor.

The COVID-19 pandemic caused by the SARS-CoV-2 virus, recognized by the World Health Organization (WHO), has led to 164,523,894 confirmed cases and 3,412,032 deaths globally as of May 20, 2021. SARS-CoV-2 encodes crucial proteases for its replication cycle, including the papain-like protease (PLpro), presenting a potential target for developing COVID-19 treatments. Mauritine, a cyclopeptide alkaloid found in the Ziziphus-spina christi plant, exhibits antiviral properties and was investigated for its affinity and toxicity towards PLpro using molecular docking through MGLTools 1.5.6 with Autodock Tools 4.2. Preceding this, toxicity and ADME prediction were performed via Toxtree 3.1.0 software and SwissADME servers. Results from molecular docking revealed free binding energy values of -8.58; -7.73; -8.36; -6.07; -6.67; -7.83; -7.67; -7.40; and -6.87 Kcal/mol for Mauritine-A, Mauritine-B, Mauritine-C, Mauritine-D, Mauritine-F, Mauritine-H, Mauritine-J, Mauritine-L, and Mauritine-M, respectively. Correspondingly, inhibition constants were 0.51724; 2.14; 0.7398; 35.43; 12.95; 1.83; 2.38; 3.80; and 9.17 µM, respectively. Interactions observed included hydrogen bonds, hydrophobic interactions, and electrostatic interactions between the Mauritine compounds and the receptor. Mauritine-A and Mauritine-C emerged as a promising anti-COVID-19 candidate due to its superior affinity compared to other derivatives, as indicated by research findings. Interestingly, Mauritine-A and Mauritine-C exhibits notable stability as depicted by the RMSD and RMSF graphs, along with a considerable MM-PBSA binding free energy value of -162.431 and -137.500 kJ/mol, respectively.Communicated by Ramaswamy H. Sarma.

In-silico, synthesis, structure elucidation and anticancer activity study of 2-(3,4-dichlorophenyl)-4H-benzo[d][1,3]oxazin-4-one.

The research aims to synthesize 2-(3,4-dichlorophenyl)-4H-benzo[d][1,3]oxazin-4-one and evaluate its anticancer activity against MCF-7. This compound was selected based on in-silico study conducted against several dihalophenylbenzoxazinone analogues using molecular docking towards Methionyl-tRNA synthetase. Synthesis of target compound was carried out using anthranilic acid and 3,4-dichlorobenzoyl chloride. The resulting compound was characterized using various spectroscopic analysis: 1D and 2D NMR, infrared and MS. In-silico studies was performed by MVD. Several designed compounds were docked into the active site on Methionyl-tRNA Synthetase (1PG2). Anticancer activity was evaluated by MTT Assay against MCF-7. 2-(3,4-dichlorophenyl)-4H-benzo[d][1,3]oxazin-4-one has been successfully synthesized with decent amount of yield 88%. Its spectroscopic analysis 1D and 2D NMR, MS, FTIR has proven the chemical structure of compound. In-silico studies toward the enzyme showed docking score of -76.04 Kcal/mol, higher than its native ligand (-93.50 Kcal/mol). Meanwhile, MTT assay result against MCF-7 showed IC50 value of 68.59ppm. Based on preliminary in-silico studies inhibited Methionyl-tRNA Synthetase, 2-(3,4-dichlorophenyl)-4H-benzo[d][1,3]oxazin-4-one was synthesized and tested in-vitro against MCF-7. Albeit the compound does not possess better docking score than native ligand, it is still argued that benzoxazine ring can be considered as a potential anticancer agent, as showed by MTT assay result which indicated moderate cytotoxicity.