Study on the mechanism of active components of Liupao tea on 3CL based on HPLC-DAD fingerprint and molecular docking technique.

Liupao tea, a drink homologous to medicine and food. It can treat dysentery, relieve heat, remove dampness, and regulate the intestines and stomach. The objective of this study is to explore the material basis and mechanism of Liupao tea intervention in COVID-19 and to provide a new prevention and treatment programme for COVID-19. We used high performance liquid chromatography to analyze the extract of Liupao tea and establish its fingerprint. The main index components of the fingerprint were determined using SARS-COV-2 3-chymotrypsin-like protease (3CL ), and an in vitro drug screening model based on fluorescence resonance energy transfer was used to evaluate its inhibitory activity in vitro. The fingerprint results showed that the alcohol extract of Liupao tea contained gallic acid, epigallocatechin gallate (EGCG), caffeine, epicatechin gallate, rutin, and ellagic acid. The molecular docking binding energies of the six index components of SARS-CoV-2 3Cl were all less than -5.0 kJ/mol and showed strong binding affinity. The results of in vitro activity showed that the IC of EGCG was 8.84 μmol/L, which could inhibit SARS-CoV-2 3Cl to a certain extent. This study unleashed that EGCG has a certain inhibitory effect on SARS-CoV-2 3CL , and Liupao tea has a certain significance as a tea drink for the prevention of COVID-19. PRACTICAL APPLICATIONS: The objective of this study was to explore the material basis and mechanism of Liupao tea intervention in COVID-19 and to provide a new prevention and treatment programme for COVID-19. The molecular docking binding energies of the six index components of Liupao tea with SARS-CoV-2 3CL were all less than -5.0 kJ/mol, among them, the enzyme activity experiment shows that EGCG has a certain inhibitory effect on SARS-CoV-2 3CL , it can be used as a potential SARS-CoV-2 3CL inhibitor. We predicted that the understandings gained in the current research may evidence that Liupao tea has a certain significance as a tea drink for the prevention of COVID-19.