2.2 Screening of the anti-SARS-CoV-2
Mpro effects of herbal products
This study screened 60 herbs with potential antiviral effects for their
inhibitory effects against SARS-CoV-2 Mpro. The
proteolytic activity of Mpro was evaluated through a
fluorescence resonance energy transfer (FRET) assay utilizing a
fluorescently tagged substrate (Dabcyl-KNSTLQSGLRK-Edans). The
procedures were conducted in a 96-well black plate, following the steps
outlined in the reported study24,25. The inhibitory
activities of LJ extract and individual constituents in LJ
anti-SARS-CoV-2 Mpro were evaluated using identical
methods mentioned above.
2.3
Global chemical
analysis of LJ by UHPLC-Q-Exactive Orbitrap HRMS
The comprehensive analysis of the components in LJ was performed using
an ultra-high performance liquid chromatography system (Dionex UltiMate
3000, Thermo Fisher Scientific) coupled to a Q-Exactive Orbitrap high
resolution mass spectrometer (Q-Exactive HRMS, Thermo Fisher
Scientific)26. The liquid chromatography and mass
spectrometry conditions are detailed in the supplementary material. To
differentiate isomers and reduce false positive results, component
identification was based on their accurate molecular weights and
comparison of retention times and tandem mass spectrometry fragmentation
patterns with reference standards.