The COVID-19 virus enters cells via the ACE2 Receptor. Blocking the ACE2 receptor with antibodies blocks the virus’ entry into cells (source) (Fig. 1).
Fig. 1: Virus entry via ACE2 binding site (https://pubmed.ncbi.nlm.nih.gov/32155444/).
The polyphenols quercetin and kaempferol have been proven to bind to the ACE2 receptor (source), other polyphenols (eg. EGCG) are also able to bind to it (source).
Quercetin has been proven to bind to the ACE2 receptor (source), and reduce patient blood pressure (source).
The binding of the aforementioned compounds to the ACE2 receptor may also reduce or prevent the COVID-19 virus’ entry into lung cells. Quercetin was recognized as one of about 20 top-scoring ligands for ACE2 docking, by the SUMMIT supercomputer (source). Quercetin has also been proven to work against rotaviruses in vitro since 1990 (source). Quercetin and its derivatives also have proven antiviral effects against RNA viruses, such as the H1N1 flu (source), Zika (source), and Ebola (source). Perhaps this means it could also be effective against the RNA virus COVID-19?
The mechanism of antiviral action of quercetin is known – it has a proven inhibitory effect on tropoisomerase 1 and 2 (source, source), which play a key role in RNA virus proliferation. Additionally quarcetin also increases ROS production in cells and thusly damages viral RNA (source). It also has proven antioxidative activity against UV or roentgen (X) rays (source), which means that users of this drug must minimize sun contact!
Animal models have also proven that quarcetin in mice models builds up in the body with chronic use (most likely because of the lipophilic nature of the molecule), which could also hold true for humans, meaining that chronic use would increase the concentration of the molecule in the body, so larger doses would not be necessary.
Scientifically proven successful prophylaxis against the flu virus by only ingesting three cups of flavonoid rich tea amongst seniors (above 80 years of age) in Japan proves, that high doses of flavonoids are not necessary for successful prevention of flu and flu-like viral infections (source).
Prophylactic oral use of the standardized plant based drug Bilobil® (contains tropoisomerase 1 and 2 inhibitor – quercetin, and tropoisomerase 2 inhibitor – kaempferol), which has antiviral effects, while also binding to ACE2 receptors, obstructing COVID-19 virus entry into cells, thus seems a reasonable preventative for COVID-19 infections, although the efficacy of this approach has not been scientifically proven.
Bilobil Forte® usage in it full recommended daily dosage (at most 2 capsules or 240 mg daily) over a span of three months, seems like a safe, effective, appropriate and cost effective way for alleged prevention or risk reduction for COVID-19 virus infections during the pandemic, with minimal negative health effects.
Health risks for this treatment that stem from the many drug interactions (ginkgo can interact with aspirin, warfarin, trazodone, omeprazole, antihypertensives and antihyperglycemics), must be reduced to a minimum before the usage of this drug.
Long term, high dosage use of this drug is disadvised.
*This post has not been proofread and reflects only the author’s views