As such, in silico studies have investigated the use of flavonoids in api-compounds as effective therapeutic candidates against COVID-19 by targeting S protein cleavage by host-cell proteases, e.g., TMPRSS2 [5], S protein binding to cell surface receptors such as ACE-II [48,51], inhibiting S protein [51,78], or S protein binding to the inflammatory B56 unit in PP2A [2] as well as by interfering with NSPs of SARS-CoV-2 in order to hamper viral replication [25,47,51]. Here, PTPA is linked to COVID-19.