Covid, “a natural compound kills it”: CNR discovery

Published on: 03/09/2020 11:24 AM

From nature the hope of a new weapon against Covid-19. An international study in which the Institute of Nanotechnology of the National Research Council, Cnr-Nanotec of Cosenza, participated, indicates that Quercetin, a naturally occurring compound, acts as a specific inhibitor of the Sars-CoV-2 coronavirus.. In fact, the substance shows a destabilizing action on 3CLpro, one of the key proteins for the replication of the pathogen. The study, supported by the Spanish Foundation hna, is published in the ‘International Journal of Biological Macromolecules’.

Along with the search for an effective vaccine, the development of specific antiviral drugs for the coronavirus responsible for Covid-19 is another important line of study that has launched the world of science to overcome the pandemic enemy. The new work, carried out by Bruno Rizzuti from Cnr-Nanotec with a group of researchers from Zaragoza and Madrid, shows that quercetin, by blocking the enzymatic activity of 3CLpro, is “lethal” for Sars-CoV-2.

“Computer simulations have shown that quercetin binds exactly to the active site of the 3CLpro protein, which prevents it from performing its function correctly – says Rizzuti, author of the computational part of the study – Already at this time this molecule is on par with the best antivirals available against the coronavirus, none of which, however, is approved as a drug. “

Quercetin, explains the CNR, has a series of original and interesting properties from a pharmacological point of view: “It is present in abundance in common vegetables such as capers, purple onion and chicory, and is known for its antioxidant, anti-inflammatory, anti-allergic and antiproliferative. Its pharmacokinetic properties are also known and it is well tolerated by humans ”. Furthermore, quercetin “can be easily modified to develop an even more powerful synthetic molecule, thanks to the small size and the particular functional groups present in its chemical structure. Since it cannot be patented, anyone can use it as a starting point for further research. “. .

“The study is based on an experimental characterization of 3CLpro, the main protease of Sars-CoV-2”, explains Olga Abian from the University of Zaragoza, first author of the publication. “This protein has a dimeric structure, made up of two identical subunits each with an active site that is essential for its biological activity. In the first phase of the work, the sensitivity to various temperature conditions was studied with various experimental techniques. and pH: an important result – underlines the scientist – because many groups are working on 3CLpro as a possible drug target, given that it is strongly conserved in all types of coronavirus. Molecules that act as inhibitors have already been reported in the literature, but cannot be used as drugs due to their side effects.“.

“The most interesting part of this job is experimental screening performed on 150 compounds, thanks to which quercetin has been identified as an active molecule in 3CLpro ”, adds Adrián Velázquez-Campoy from the University of Zaragoza, who led the research group and has already worked on the research of protein inhibitor drugs for the Sars virus original. that caused the 2003 outbreak of severe acute respiratory syndrome.

“Quercetin reduces the enzymatic activity of 3CLpro due to its destabilizing effect on the protein. Obviously, we have to find a vaccine – says the expert – but the drugs will still be necessary for people already infected and for those who cannot be vaccinated. Therefore, the search for new molecules aims to administer a combination of different compounds, to minimize drug resistance and the development of new viral strains ”.