Probable mechanism of hydroxychloroquine (HC) against SARS-CoV-2: The figure depicts the mechanism of action of hydroxychloroquine targeting the SARS-CoV-2 through many ways. (1) The hydroxychloroquine has the ability to constrain the quinone reductase-2 which is an essential agent required for the biosynthesis of sialic acid (SA) which is generally used as the receptor moieties by the SARS-CoV-2. (2) The hydroxychloroquine could change the pH of lysosomes that leads to inhibition of the cathepsins which is mandatory for the formation of autophagosomes to cleave the SARS-CoV-2 spike (S1 and S2) protein and blocks the viral attachment to the human host receptors. (3) The drug also targets the virus through increasing the endosomal pH and hinders the glycosylation process of the cellular receptors of SARS-CoV-2, which eventually blocks the viral attachment to the ACE2 receptors and inhibits the viral infection. (4) Moreover, the hydroxychloroquine obstructs the MAP-kinase pathway which results to SARS-CoV-2 virus molecular crosstalk resulting into alteration of viral assembly and also intrude the proteolytic process of the M protein of the virus.
