Ciluprevir

The novel coronavirus disease (COVID-19) is caused by a new strain (SARS-CoV-2) that erupted in 2019. Nowadays, it is a great threat that claims uncountable lives worldwide. There is no specific chemotherapeutics developed yet to combat COVID-19. Therefore, scientists have been devoted to the quest of the medicine that can cure COVID-19.

Existing antivirals, such as ASC09/ritonavir, lopinavir/ritonavir with or without umifenovir in combination with antimalarial chloroquine or hydroxychloroquine, have been repurposed to fight the current coronavirus epidemic. Exact biochemical mechanisms of these drugs towards COVID-19 have not been discovered to date.

In-silico molecular docking can predict the mode of binding to sort out the existing chemotherapeutics having a potential affinity towards inhibition of the COVID-19 target. An attempt has been made in the present work to carry out docking analyses of 34 drugs, including antivirals and antimalarials, to explain explicitly the mode of interactions of these ligands towards the COVID-19protease target.

13 compounds having good binding affinity have been predicted towards protease binding inhibition of COVID-19.

Our in silico docking results have been confirmed by current reports from clinical settings through the citation of suitable experimental in vitro data available in the published literature.

Drugs containing thiazole and aminothiazole groups are known to generate reactive metabolites (RMs) catalyzed by cytochrome P450s (CYPs). These RMs can covalently modify essential cellular macromolecules and lead to toxicity and induce idiosyncratic adverse drug reactions. Molecular docking and quantum chemical hybrid DFT study were carried out to explore the molecular mechanisms involved in the biotransformation of thiazole (TZ) and aminothiazole (ATZ) groups leading to RM epoxide, S-oxide, N-oxide, and oxaziridine. The energy barrier required for the epoxidation is 13.63 kcal/mol, that is lower than that of S-oxidation, N-oxidation, and oxaziridine formation (14.56, 17.90, and 20.20, kcal/mol respectively). The presence of the amino group in ATZ further facilitates all the metabolic pathways, for example, the barrier for the epoxidation reaction is reduced by ∼2.5 kcal/mol. Some of the RMs/their isomers are highly electrophilic and tend to form covalent bonds with nucleophilic amino acids, finally leading to the formation of metabolic intermediate complexes (MICs). The energy profiles of these competitive pathways have also been explored.