August 14, a research article studying a new potential drug for SARS-CoV-2 was published on the Science Advances website. Through the efforts of drug repurposing studies, many pre-existing drugs were identified to have potential activity against the current Coronavirus strain. Among the discovered drugs is Ebselen, an organic selenium compound with antioxidant and anti-inflammatory properties.
Ebselen has a chemical formula of 2-Phenyl-1,2-benzoselenazol-3-one. It was one of the drugs that possessed promising results against one of the virus’s cysteine proteases, the main protease (Mpro). A protease is an enzyme that speeds up the breakdown of proteins. In the life cycle of a SARS-CoV virus strain, the Mpro plays a vital role in the development of the proteins being used for gene translation and therefore, in the overall viral replication process.
Other structural parts of the virus that are being targeted by developing drugs are the spike protein and RNA polymerase.
In the new study, drug candidates were screened for their ability to stop the activity of Mpro. Ebselen was already mentioned in another study that also searched for inhibitors of Mpro.
Ebselen showed the most encouraging results from that study and was pursued further. In assays using biological cells, Ebselen showed incredible antiviral activity. Other previous indications for Ebselen include anti-inflammatory, antioxidant, and cytoprotection. It also possesses bactericidal activity at low doses for S. aureus bacteria strains that were already resistant to multiple antibiotics.
The drug has low toxicity to biological cells and has proven to be safe for human use in many clinical trials. With all this information to start, Ebselen is a strong contender to be considered for future studies as a Covid medication.
Via the AMBER18 simulation package, the researchers were able to generate computational analysis on the mechanism of action of Ebselen. The drug will be able to bind to two sites - first on the actual site of enzyme catalysis, and the other on the allosteric site, where the inhibitor molecule is able to alter the enzyme’s conformational structure.