3.2 Global chemical analysis of LJ
The chemical components of herbal medicines are extremely complex, with a significant proportion being trace or minor constituents31. To comprehensively identify the chemical components in LJ, we employed UHPLC-Q-Exactive Orbitrap HRMS for the analysis of this herbal extract. The structures of the components were determined by comparing their LC-MS characteristics,i.e. retention time, exact molecular weight, and tandem mass spectrometry fragmentation pattern, with reference standards, compounds reported in the literature, as well as those registered in PubChem or other databases. Under the optimized chromatography and mass spectrometry conditions, a total of 50 components in all were identified, including organic acids, flavonoids, catechins and terpenoids (Fig. S3, S5-S54 and Table S1 ). Notably, some flavonoids (e.g., quercetin and luteolin) and catechins (e.g., gallic acid and caffeic acid) in LJ contain one or more catechol groups in their structures, which are susceptible to oxidation and formo -quinone. These o -quinones have the potential to form covalent bonds with the cysteines of Mpro17,32,33.