Background and objective Coronavirus disease (COVID-19) is an ongoing pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Due to the incessant spread of the disease with substantial morbidity and mortality rates, there is an urgent demand for effective therapeutics and vaccines to control and diminish this pandemic. A critical step in the crosstalk between the virus and the host cell is the binding of SARS-CoV-2 spike protein to the angiotensin-converting enzyme 2 (ACE2) receptor present on the surface of the host cells. Hence, inhibition of this interaction could be a promising strategy to combat the SARS-CoV-2 infection. Methods Docking and Molecular Dynamics (MD) simulation studies revealed that designed peptide maintains their secondary structure and provide a highly specific and stable binding (blocking) to SARS-CoV-2. Results We have designed a novel peptide that could inhibit SARS-CoV-2 spike protein interaction with ACE2, thereby blocking the cellular entry of the virus. Conclusion Our findings suggest that computationally developed inhibitory peptide may be developed as an anti-SARS-CoV-2 agent for the treatment of SARS-CoV-2 infection. We further plan to pursue the peptide in cell-based assays and eventually for clinical trials.

With the rapid growth of the COVID-19 (coronavirus disease 2019) pandemic across the globe, therapeutic attention must be directed to fight the novel severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). However, developing new antiviral drugs and vaccine development is time-consuming, so one of the best solutions to tackle this virus at present is to repurpose ready-to-use drugs. This paper proposes the repurposing of the Food and Drug Administration (FDA)-approved, purchasable, and naturally occurring drugs as a dual-inhibitor for the SARS-CoV-2 cysteine proteases—3Chemotrypsin-like protease or main protease (3CL pro or M pro ) and Papain-like protease (PL pro )—that are responsible for processing the translated polyprotein chain from the viral RNA-yielding functional viral proteins. For virtual screening, an unbiased, blind docking was performed, which produced the top six dual-inhibition candidates for 3CL pro and PL pro . The six repurposed drugs that have been proposed block the catalytic dyad His41 and Cys145 of 3CL pro as well as the catalytic triad Cys111, His272, and Asp286 along with oxyanion hole-stabilizing residue Trp106 of PL pro in the crystal structure. Repurposing such naturally occurring drugs will not only pave the way for rapid in vitro and in vivo studies to battle the SARS-CoV-2 but will also expedite the quest for a potent anti-coronaviral drug.

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Copper-chitosan nanoparticle (CuChNp) was synthesized and used to study its effect on finger millet plant as a model plant system. Our objective was to explore the efficacy of CuChNp application to control blast disease of finger millet. CuChNp was applied to finger millet either as a foliar spray or as a combined application (involving seed coat and foliar spray). Both the application methods enhanced growth profile of finger millet plants and increased yield. The increased yield was nearly 89% in combined application method. Treated finger millet plants challenged with Pyricularia grisea showed suppression of blast disease development when compared to control. Nearly 75% protection was observed in the combined application of CuChNp to finger millet plants. In CuChNp treated finger millet plants, a significant increase in defense enzymes was observed, which was detected both qualitatively and quantitatively. The suppression of blast disease correlates well with increased defense enzymes in CuChNp treated finger millet plants.

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E)-N'-(substituted-benzylidene)-2-(7-fluoro-2-methoxyquinolin-8-yl) acetohydrazide-hydrazone derivatives reported in this manuscript represents a new series of antibacterial agents as well as the DNA gyrase inhibitors. Efforts were made to synthesize these quinolone-acetohydrazide-hydrazone derivatives (9a-n) in excellent yields. All the target compounds were evaluated for their in vitro antimicrobial activity against Escherichia coli (MTCC 443), Pseudomonas aeruginosa (MTCC 424) as specimens for Gram-negative bacteria, and Staphylococcus aureus (MTCC 96) and Staphylococcus pyogenes (MTCC 442) as specimens for Gram-positive bacteria. Excellent antibacterial activity was observed for compounds substituted with R=3,4,5-trimethoxy, 4-F, 4-OCF3, 4-CF3 , 3-CF3 moieties. Derivatives 9a-n were docked into the active sites of DNA gyrase A and DNA gyrase B in order to get more insight into the binding mode of the compounds. Among all derivatives, 9n showed a least binding energy as -91.6 kcal/mol was the best among all compounds for DNA gyrase A. DNA gyrase enzyme inhibtion assay favors the compound 9m and 9n, which were substituted with di-fluorine moieties (R = 2,4difluoro and 3,4-difluoro) in the quinoline scaffold, as the most potent inhibitors with of S. aureus DNA gyrase A (9mIC50 0.14 mg/mL and 9nIC50 0.19 mg/mL).

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