Researchers in India have presented a large body of evidence that highlight quercetin-a flavonoid molecule found in many common fruits and vegetables that could be developed into drug therapies used to combat COVID-19. Flavonoids are polyphenolic molecules that can be abundantly found in plants. Quercetin is present in most fruits and vegetables and has a variety of benefits, including prevention against cardiovascular and neurodegenerative diseases, and protection against cancer, arthritis, diabetes, and many more.
In the current study, the researchers gathered numerous publications relating to flavonoids, quercetin, COVID-19, and drug design to provide evidence that a quercetin-based compound may be effective in disarming COVID-19. They also performed molecular docking analyses, using 3D structures of ten key proteins of COVID-19, and estimating binding affinity to each of these regions by quercetin. Molecular docking by quercetin to the receptor-binding domain (RBD) was shown to be good in three active sites of the RBD: SER349, LEU441, and ASN450. Additional resides of the spike protein (ASP88, ASP198, ILE233, and ILE235) also showed good docking affinity, representing further targets for drug therapies.
These results suggest that quercetin may be effective in preventing entry of SARS-CoV-2 to human cells, as it has high binding efficiency to the virus spike protein. Furthermore, quercetin appears to broadly bind to active sites on the virus, but not with sites of human ACE2. This is crucial, as if quercetin were to also disable ACE2, this would have a greater detrimental effect on the cell and, by extension, the human body.