We talked about it back in March when a Canadian team observed that quercetin, a substance with antiviral properties, could be used as a drug against novel coronavirus. Five months have passed since then and research on quercetin has continued, also carried out by other research groups. A few weeks ago a study published in the International Journal of Biological Macromolecules was published by a team from the University of Zaragoza and by the Italian CNR (Abian et al, Int J Biol Macromol., Aug 2020) in which it is explained how the quercetin is actually able to inhibit the replication of the novel coronavirus or Sars-Cov-2.
There is a protein, called 3CLpro, which is the key protein through which the novel coronavirus replicates. 3CLpro is also common to other types of coronaviruses. The scientists, in their research, first characterized this protein by studying it under different pH and temperature conditions. This data may be useful for further research aiming at using 3CLpro as a drug target. Then, the researchers performed a test on 150 compounds to evaluate which one could bind to 3CLpro, by inhibiting it. What emerged was that quercetin was able to bind to the protein, destabilizing it and reducing its activity. Therefore, quercetin can be considered a substance capable of inhibiting the replication of the novel coronavirus with the advantage that it is naturally present, is very well tolerated and cannot be patented. At present, however, there is no quercetin-based drug but this research certainly pays the way for promising future developments for the realization of treatments against the novel coronavirus.
In the meantime, supplementing your diet with foods rich in quercetin can help strengthen the immune system to cope with external attacks. Quercetin, in fact, is contained in apples, berries, capers, grapes, onions, tea, tomatoes, walnuts, shallots and vegetables of the cruciferous family such as cauliflower and broccoli.