SARS-COV-2, the novel coronavirus and root of global pandemic COVID-19 caused a severe health threat throughout the world. Lack of specific treatments raised an effort to find potential inhibitors for the viral proteins. The recently invented crystal structure of SARS-CoV-2 main protease (M pro) and its key role in viral replication; non-resemblance to any human protease makes it a perfect target for inhibitor research. This article reports a computer-aided drug design (CADD) approach for the screening of 118 compounds with 16 distinct heterocyclic moieties in comparison with 5 natural products and 7 repurposed drugs. Molecular docking analysis against M pro protein were performed finding isatin linked with a oxidiazoles (A2 and A4) derivatives to have the best docking scores of À11.22 kcal/ mol and À11.15 kcal/mol respectively. Structure-activity relationship studies showed a good comparison with a known active M pro inhibitor and repurposed drug ebselen with an IC 50 value of À0.67 lM. Molecular Dynamics (MD) simulations for 50 ns were performed for A2 and A4 supporting the stability of the two compounds within the binding pocket, largely at the S1, S2 and S4 domains with high binding energy suggesting their suitability as potential inhibitors of M pro for SARS-CoV-2.

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An ultrasound assisted multi‐component synthesis of a series of 2‐(N‐heterocycle) substituted 1,3,4‐oxadiazoles have been performed. A proper IR, UV, Mass and NMR spectral analysis supported the 12 synthesized novel compounds. Compound 5‐bromo‐1‐((4‐chlorophenyl)((5‐(4‐hydroxyphenyl)‐1,3,4‐oxadiazol‐2‐yl)amino)methyl) indoline‐2,3‐dione (D8), displayed significant cytotoxicity against all the three human cancer cell lines studied in this article (breast cancer cell line MCF‐7, colorectal cancer cell line HT‐29 and liver cancer cell line Hep G2) using MTT assay. Further in silico target hunting using Chem Mapper led to the identification of two important cancer targets; EGFR and CDK2 kinases. Compound D8 was studied in detail using AutoDock and displayed high binding energies with the two proteins. Quantum chemical calculations of the designed compound D8 at the active site with specific amino acids for both the proteins showed stronger interactions at the active sites similar to the docking studies.

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A series of hybrid analogs of barbituric/thiobarbituric acid and 1,3,4‐oxa/thiadiazoles were synthesized by a sequence of diazotization and coupling reaction. Structures of all the synthesized compounds were confirmed by IR, NMR and mass spectroscopy. All the compounds were tested by in vitro 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) based assay against two human cancer cell lines: human breast adenocarcinoma cell line MCF‐7 and colorectal adenocarcinoma cell line HT‐29. Compound 11 which contained 1,3,4‐thiadiazole ring, p‐NO2‐phenyl group and thiobarbituric acid moiety displayed activity better than that of the standard drug Doxorubicin (DOX) used in the study. Target hunting and computational docking studies were used to explain the interactions between compound 11 and the potential targets.

Silkworm, Bombyx mori (B. mori) belongs to the Lepidoptera family. The silk produced from this insect, mulberry silk, gained lot of importance as a fabric. Silk is being exploited as a biomaterial due to its surprising strength and biocompatibility. Polyamines (PA) are important cell growth regulators. In the present work the effect of treatment of polyamines, putrescine (Put), spermidine (Spd), and spermine (Spm) on the quantity and quality of silk produced was assessed. Results showed that exogenous feeding of Spd at a concentration of 50 µM increased fiber length significantly. Analysis by Fourier transform infrared (FTIR) on the properties of silk obtained from Spd treated silkworms revealed an increase in percentage of absorption with no difference in peak positions of amide I and amide III groups. Scanning electron microscopy (SEM) revealed an increase in diameter of silk. Further, analysis at molecular level showed an increase in fibroin expression in Spd treated silk glands. However, the Spd treatment showed no significant difference with respect to fibroin to sericin ratio per unit weight of cocoon, silk tenacity, and percent elongation. Thus, the present results show that polyamine treatment would influence silk quality at structural, mechanical, and molecular level in the Bombyx mori, which can be exploited in silk biomaterial production.

Biologically relevant azolo (triazolo and thiazolo) diazonium salts were coupled with 2,4-pentanedione. The resulting substituted 2,4-pentanedione (L 1 and L2) were condensed with 1,6-diaminohexane in the presence of chloride salts of nickel(II), copper(II), platinum(lI), platinum(IV) and palladium(II) or nickel(II) and copper(II) acetates. The resulting dinuclear/polynuclear complexes were characterized by elemental analyses, conductance and magnetic moments, as well as i.r., u.v.-vis., 1H n.m.r. and e.s.r, spectra.