Oroxylin A is a severe acute respiratory syndrome coronavirus 2-spiked pseudotyped virus blocker obtained from Radix Scutellariae using angiotensin-converting enzyme II/cell membrane chromatography

Phytother Res. 2021 Jun;35(6):3194-3204. doi: 10.1002/ptr.7030. Epub 2021 Feb 15.


The current worldwide outbreak of the coronavirus disease 2019 (COVID-19) has been declared a public health emergency. The angiotensin-converting enzyme II (ACE2) has been reported as the primary host-cell receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative virus of COVID-19. In this study, we screened ACE2 ligands from Radix Scutellariae and investigated its suppressive effect on SARS-CoV-2 spiked pseudotyped virus in vitro. HEK293T cells stably expressing ACE2 receptors (ACE2 cells) were used to provide the receptor for the ACE2/cell membrane chromatography (CMC) method used for analysis. The SARS-CoV-2-spiked pseudotyped virus was used to examine the anti-viropexis effect of the screened compounds in ACE2 cells. Molecular docking and the surface plasmon resonance (SPR) assay were used to determine the binding properties. Oroxylin A exhibited an appreciable suppressive effect against the entrance of the SARS-CoV-2-spiked pseudotyped virus into ACE2 cells, which showed good binding to ACE2 as determined using SPR and CMC. Oroxylin A was shown to be a potential candidate in the treatment for COVID-19 by virtue of its blocking the entrance of SARS-CoV-2 into ACE2 cells by specifically binding to the ACE2 receptor.

Keywords: ACE2; CMC; COVID-19; Oroxylin A; Radix Scutellariae.

MeSH terms

  • Angiotensin-Converting Enzyme 2 / metabolism
  • COVID-19 Drug Treatment*
  • Cell Membrane / metabolism
  • Chromatography
  • Flavonoids / pharmacology*
  • HEK293 Cells
  • Humans
  • Molecular Docking Simulation
  • Protein Binding / drug effects
  • SARS-CoV-2 / drug effects*
  • Scutellaria baicalensis / chemistry*


  • Flavonoids
  • 5,7-dihydroxy-6-methoxy-2-phenylchromen-4-one
  • Angiotensin-Converting Enzyme 2