TMPRSS2 and COVID-19: Therefore, quercetin, glabridin, gallic acid, or chrysoeriol (luteolin derivative) can effectively attenuate endothelial dysfunction and inflammation via inhibition of ACE2/TMPRSS2, NOX2-dependent superoxide production, and MCP-1, leading to abrogation of ARDS/multi-organ failure and mortality in patients with COVID-19.