Discovery of Potential SARS-CoV-2 Main Protease Inhibitory Compounds from Medicinal Plants

Overview

The novel coronavirus (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has evolved into a global pandemic. Veklury, the sole FDA-approved drug, appears to be limited in terms of efficacy. The purpose of this study was to screen the antiviral activity of extracts from four plants (i.e., Lonicera japonica, Glycyrrhiza glabra, Isatis indigotica, and Scutellaria baicalensis) and to identify potential bioactive compounds against SARS-CoV-2 main protease (3C-like Protease). Butanol and ethyl acetate (EtOAc) fractions of the crude plant extracts on 3C-like Protease assays underwent high throughput screening. The EtOAc fraction of the L. japonica extract displayed significantly higher inhibitory activity on the 3C-like protease compared to all other fractions. Further analysis of the L. japonica EtOAc fraction using liquid chromatography and tandem mass spectrometry with molecular networking revealed five potential compounds as potential inhibitory candidates against SARS-CoV-2 main protease. The compounds of secologanin and luteolin-7-glucoside, based on their cosine scores of over 0.9, were selected as potential drug development compounds for inhibiting COVID-19. Thus, L. japonica could be a potentially promising drug development target for COVID-19.