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The multifaceted nature of Alzheimer’s disease (AD) demands treatment with multitarget-directed ligands (MTDLs) to confront the key pathological aberrations. A novel series of triazinoindole derivatives were designed and synthesized. In vitro studies revealed that all the compounds showed moderate to good anticholinesterase activity; the most active compound 23e showed an IC50 value of 0.56 ± 0.02 μM for AChE and an IC50 value of 1.17 ± 0.09 μM for BuChE. These derivatives are also endowed with potent antioxidant activity. To understand the plausible binding mode of the compound 23e, molecular docking studies and molecular dynamics simulation studies were performed, and the results indicated significant interactions of 23e within the active sites of AChE as well as BuChE. Compound 23e successfully diminished H2O2-induced oxidative stress in SH-SY5Y cells and displayed excellent neuroprotective activity against H2O2 as well as Aβ-induced toxicity in SH-SY5Y cells in a concentration dependent manner. Furthermore, it did not show any significant toxicity in neuronal SH-SY5Y cells in the cytotoxicity assay. Compound 23e did not show any acute toxicity in rats at doses up to 2000 mg/kg, and it significantly reversed scopolamine-induced memory deficit in mice model. Additionally, compound 23e showed notable in silico ADMET properties. Taken collectively, these findings project compound 23e as a potential balanced MTDL in the evolution process of novel anti-AD drugs.

The Co rona vi rus D isease (COVID-19) is caused because of novel coronavirus (SARS-CoV-2) pathogen detected in China for the first time, and from there it spread across the globe creating a worldwide pandemic of severe respiratory complications. The virus requires structural and non-structural proteins for its multiplication that are produced from polyproteins obtained by translation of its genomic RNA. These polyproteins are converted into structural and non-structural proteins mainly by the main protease (Mpro). A systematic screening of a drug library (having drugs and diagnostic agents which are approved by FDA or other world authorities) and the Asinex BioDesign library was carried out using pharmacophore and sequential conformational precision level filters using the Schrodinger Suite. From the screening of approved drug library, three antiviral agents ritonavir, nelfinavir and saquinavir were predicted to be the most potent Mpro inhibitors. Apart from these pralmorelin, iodixanol and iotrolan were also identified from the systematic screening. As iodixanol and iotrolan carry some limitations, structural modifications in them could lead to stable and safer antiviral agents. Screenings of Asinex BioDesign library resulted in 20 molecules exhibiting promising interactions with the target protein Mpro. They can broadly be categorized into four classes based on the nature of the scaffold, viz. disubstituted pyrazoles, cyclic amides, pyrrolidine-based compounds and miscellaneous derivatives. These could be used as potential molecules or hits for further drug development to obtain clinically useful therapeutic agents for the treatment of COVID-19. Graphic abstract Electronic supplementary material The online version of this article (10.1007/s11030-020-10130-1) contains supplementary material, which is available to authorized users.

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