Now, Chen and the team have published a review summarizing some recent findings regarding the potential effectiveness of natural products and herbal medicines in the inhibition of SARS-CoV-2 infection.
For example, they discuss compounds derived from natural products that may be effective against the cellular receptor heat shock protein A5 (HSPA5).
Some studies have reported that HSPA5 is recognized by the SARS-CoV-2 spike protein and one 2020 study showed that the phytoestrogens daidzein, genistein, formononetin, and biochanin A have binding affinities with HSPA5.
The researchers say these medicinal, plant-derived compounds may disrupt the attachment of SARS-CoV-2 to host cells (through spike), although their antiviral bioactivity requires further investigation.
The host cell enzyme transmembrane protease serine 2 (TMPRSS2) facilitates the entry of SARS-CoV-2 into host cells. Inhibition of this enzyme blocks the spike protein's ability to fuse with the host cell receptor angiotensin-converting enzyme 2 (ACE2).
Using molecular docking and molecular dynamics simulations, one study conducted earlier this year demonstrated that withanone, a compound that can be isolated from Ashwagandha leaves (Withania somnifera) could bind to the catalytic site of TMPRSS2.
That study also confirmed that withanone significantly downregulated TMPRSS2 in the breast cancer cell line MCF-7, thereby pointing to its potential to dampen this enzyme's function.