Oxadiazoles for Covid-19?

Oxadiazoles are a class of heterocyclic aromatic chemical compounds, having different isomeric forms. They appear in a variety of pharmaceutical drugs. Among the drugs based on the 1,3,4-oxadiazole ring, we find for instance an antiviral such as Raltegravir, which is used to treat HIV/AIDS. Here we will discuss Raltegravir and in-silico simulations concerning SARS-COV-2. Besides the compounds based on 1,3,4 rings, there exist those with 1,2,4-oxadiazole rings which are reported as anti-inflammatory and analgesic agents. One of these drugs is Oxolamine. Of this drug we will stress the fact that it is an inhibitor of the formation of N-acetylneuraminic acid, a sialic acid. Let us stress that the main target of SARS-COV-2 is considered the ACE2 receptor. Then, is the sialic acid supporting the virus to enter the cell? A study, 10.1021/acscentsci.0c00855, that used a glyco-nanoparticle platform, reported the discovery that N-acetyl neuraminic acid has affinity toward the SARS-COV-2 spike glycoprotein, that is a glycan-binding function. However, a recent study, 10.1016/j.scib.2021.01.010, which has investigated the binding of the spikes of the virus by means of micro-arrays, tells that no binding with sialic acid residues was detected. On 8 March 2021, a bioRxiv preprint 10.1101/2021.03.08.434228 has been published evidencing a sialic acid-dependent binding and viral entry of SARS-CoV-2. In any case, since the sialic acids have an antiviral protective role, it could be relevant to investigate carefully any ligand/protein docking property of Oxolamine (docking with human enzymes, virus enzymes and proteins). Based on the 1,2,4-oxadiazole scaffold, we have also the antiviral Pleconaril, that has been investigated by means of in-silico simulated interactions with SARS-COV-2 proteins. We will discuss also some news oxadiazole compounds, which are given as selective COX-2 inhibitors, antioxidant agents and inhibitors of proteins of the virus, according to in-silico simulations. Therefore, can these drugs have a possible role in the treatment of Covid-19? Or, why can't they be used for?