In silico pharmacokinetic and molecular docking studies of natural flavonoids and synthetic indole chalcones against essential proteins of SARS-CoV-2.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is distinctly infective and there is an ongoing effort to find a cure for this pandemic. Flavonoids exist in many diets as well as in traditional medicine, and their modern subset, indole-chalcones, are effective in fighting various diseases. Hence, these flavonoids and structurally similar indole chalcones derivatives were studied in silico for their pharmacokinetic properties including absorption, distribution, metabolism, excretion, toxicity (ADMET) and anti-SARS-CoV-2 properties against their proteins, namely, RNA dependent RNA polymerase (rdrp), main protease (Mpro) and Spike (S) protein via homology modelling and docking. Interactions were studied with respect to biology and function of SARS-CoV-2 proteins for activity. Functional/structural roles of amino acid residues of SARS-CoV-2 proteins and, the effect of flavonoid and indole chalcone interactions which may cause disease suppression are discussed. The results reveal that out of 23 natural flavonoids and 25 synthetic indole chalcones, 30 compounds are capable of Mpro deactivation as well as potentially lowering the efficiency of Mpro function. Cyanidin may inhibit RNA polymerase function and, Quercetin is found to block interaction sites on the viral spike. These results suggest flavonoids and their modern pharmaceutical cousins, indole chalcones are capable of fighting SARS-CoV-2. The in vitro anti-SARS-CoV-2 activity of these 30 compounds needs to be studied further for complete understanding and confirmation of their inhibitory potential.

Indole chalcones: Design, synthesis, in vitro and in silico evaluation against Mycobacterium tuberculosis.

Indole chalcones were designed and synthesized as a promising set of compounds against H37Rv strain of Mycobacterium tuberculosis. Within this library of compounds, (E)-1-(furan-3-yl)-3-(1H-indol-3-yl)prop-2-en-1-one (18), (E)-3-(1H-indol-3-yl)-1-(thiophen-2-yl)prop-2-en-1-one (20) and (E)-2-((1H-indol-2-yl)methylene)cyclopentan-1-one (24) displayed high anti-tubercular activity at 50 µg/ml with MIC values of 210, 197 and 236 µM respectively. The in-silico studies revealed that compound 18 exhibit binding modes similar to FAS-II inhibitors like INH or Thiolactomycin against KasA protein. Cytotoxicity assay results suggest that the compounds 18, 20 and 24 are non-cytotoxic to human megakaryocytes and murine B cells.