Plitidepsin is a compound, discovered and isolated in a marine invertebrate, Aplidium Albicans, that induced specific targeted cellular disruption that is capable of controlling certain types of coronaviruses.
The coronavirus enters into a healthy cell and delivers its RNA, which is protected by, among others, a protein called N.
In order to reproduce, the virus needs to use the cells it invades. In this way, the N protein of the coronavirus binds to the elongation factor eEF1A that is present in human cells. It is this virus-host binding of the N protein to eEF1A that allows the virus to replicate inside the cell.
When the amount of virus inside the cell increases, it makes the cell unviable and expels it. The virus then spreads to other cells.
Plitidepsin binds to the elongation factor eEF1A and inhibits it, preventing the binding of the N-protein, thereby interrupting the virus-human protein interaction required by the virus.
In this way, the virus cannot replicate inside the cell, propagation therefore, not being viable.
This is how plitidepsin inhibits the multiplication and spread of the SARS Cov2 virus.