Study on the potential of Sanghuangporus sanghuang and its components as COVID-19 spike protein receptor binding domain inhibitors

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has led to the most severe global pandemic, which began in Wuhan, China. Angiotensin-converting enzyme 2 (ACE2) combines with the spike protein of SARS-CoV-2, allowing the virus to cross the membrane and enter the cell. SARS-CoV-2 is modified by the transmembrane protease serine 2 (TMPRSS2) to facilitate access to cells. Accordingly, ACE2 and TMPRSS2 are targets of vital importance for the avoidance of SARS-CoV-2 infection. Sanghuangporus sanghuang (SS) is a traditional Chinese medicine that has been demonstrated to have antitumor, antioxidant, anti-inflammatory, antidiabetic, hepatoprotective, neuroprotective and immunomodulatory properties. In this paper, we demonstrated that SS decreased ACE2 and TMPRSS2 expression in cell lines and a mouse model without cytotoxicity or organ damage. Liver and kidney sections were confirmed to have reduced expression of ACE2 and TMPRSS2 by immunohistochemistry (IHC) assessment. Then, hispidin, DBA, PAC, PAD and CA, phenolic compounds of SS, were also tested and verified to reduce the expression of ACE2 and TMPRSS2. In summary, the results indicate that SS and its phenolic compounds have latent capacity for preventing SARS-CoV-2 infection in the future.