Related Experiment Video
Updated: Sep 23, 2025
Production of Pseudotyped Particles to Study Highly Pathogenic Coronaviruses in a Biosafety Level 2 Setting
Published on: March 1, 2019
Polygoni multiflori radix extracts inhibit SARS-CoV-2 pseudovirus entry in HEK293T cells and zebrafish larvae
Xiaoyang Wang1, Shengying Lin1, Roy Wai-Lun Tang1
1Center for Chinese Medicine, Clear Water Bay, Kowloon, Hong Kong, China; State Key Laboratory of Molecular Neuroscience, Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Background:
Globally, COVID-19 has caused millions of deaths and led to unprecedented socioeconomic damage. There is therefore, in addition to vaccination, an urgent need to develop complementary effective treatments and/or protective and preventative therapies against this deadly disease.
Methods:
Here, a multi-component testing platform was established to screen a library of herbal extracts from traditional Chinese medicine (TCM), to identify potent herbal extracts/phytochemicals as possible therapeutics for COVID-19. We utilized assays for spike protein (S-protein) binding to angiotensin-converting enzyme II (ACE2); the enzymatic inhibition of 3CL protease; and entry of the SARS-CoV-2 pseudovirus into cultured HEK293T cells and zebrafish larvae.
Results:
Over a thousand herbal extracts were screened and approximately 20 positive hits were identified. Among these, we found that the water and ethanol extracts of Polygoni Multiflori Radix (PMR) significantly inhibited S-protein binding to ACE2, 3CL protease activity, and viral entry into the cell and fish models. The water extract was more effective than the ethanol extract, with IC50 values of 25 to 500 µg/ml. In addition, the polysaccharide-depleted fraction of the former, and epigallocatechin gallate (EGCG) which was found in both extracts, displayed significant antiviral activity.
Conclusions:
Our results indicate that the water and ethanol extracts of PMR have an inhibitory effect on SARS-CoV-2 pseudovirus host-cell entry. Furthermore, EGCG might be an active component of PMR, which blocks SARS-CoV-2 entry to cells. Taken together, our findings suggest that PMR might be considered as a potential treatment for COVID-19.
Insights
Traditional Chinese Medicine (TCM) extracts, particularly Polygoni Multiflori Radix (PMR), show promise in inhibiting SARS-CoV-2 entry. Epigallocatechin gallate (EGCG) may be a key active component in these potent COVID-19 therapeutics.
Area of Science:
- Pharmacology
- Virology
- Traditional Chinese Medicine
Background:
- COVID-19 pandemic necessitates novel therapeutic strategies beyond vaccination.
- Urgent need for effective treatments and preventative therapies against SARS-CoV-2.
Purpose of the Study:
- Screen Traditional Chinese Medicine (TCM) herbal extracts for COVID-19 therapeutics.
- Identify potent herbal extracts and phytochemicals inhibiting SARS-CoV-2.
Main Methods:
- Established a multi-component platform screening over 1000 TCM extracts.
- Assayed for S-protein/ACE2 binding, 3CL protease inhibition, and pseudovirus entry in cell and zebrafish models.
- Identified Polygoni Multiflori Radix (PMR) extracts as potent inhibitors.
Main Results:
- Identified ~20 positive hits from over 1000 screened TCM extracts.
- PMR water and ethanol extracts significantly inhibited S-protein binding, 3CL protease activity, and viral entry.
- Epigallocatechin gallate (EGCG) in PMR extracts demonstrated significant antiviral activity.
Conclusions:
- PMR extracts exhibit inhibitory effects against SARS-CoV-2 pseudovirus host-cell entry.
- EGCG is a potential active component of PMR blocking viral entry.
- PMR presents potential as a COVID-19 therapeutic agent.
