Epigallocatechin-3-Gallate, the Main Polyphenol in Green Tea, Inhibits Porcine Epidemic Diarrhea Virus In Vitro.

Changchao Huan,Haochun Pan,Weiyin Xu,Bo Ni,Lin Li,Tingting Guo,Luyao Jiang,Jingting Yao,Song Gao

doi:10.3389/fphar.2021.628526

Abstract

There are currently no licensed drugs against porcine epidemic diarrhea virus (PEDV), but vaccines are available. We identified a natural molecule, epigallocatechin-3-gallate (EGCG), the main polyphenol in green tea, which is effective against infection with PEDV. We used a variety of methods to test its effects on PEDV in Vero cells. Our experiments show that EGCG can effectively inhibit PEDV infections (with HLJBY and CV777 strains) at different time points in the infection using western blot analysis. We found that EGCG inhibited PEDV infection in a dose-dependent manner 24 h after the infection commenced using western blotting, plaque formation assays, immunofluorescence assays (IFAs), and quantitative reverse-transcriptase PCR (qRT-PCR). We discovered that EGCG treatment of Vero cells decreased PEDV attachment and entry into them by the same method analysis. Western blotting also showed that PEDV replication was inhibited by EGCG treatment. Whereas EGCG treatment was found to inhibit PEDV assembly, it had no effect on PEDV release. In summary, EGCG acts against PEDV infection by inhibiting PEDV attachment, entry, replication, and assembly.

Highlights

Porcine epidemic diarrhea (PED) is characterized by acute villus atrophy and congestion, severe watery diarrhea, dehydration and death
Vero cells were pretreated with different concentrations of EGCG for 1 h and infected with porcine epidemic diarrhea virus (PEDV) HLJBY (0.1 MOI) or PEDV CV777 (0.1 MOI) for different time periods with EGCG present
We determined the inhibitory effect of PEDV HLJBY infection on the cells for the 24 h period by western blotting, plaque formation assays, immunofluorescence assays (IFAs) and quantitative reverse-transcriptase PCR (qRT-PCR)

Summary

Introduction

Porcine epidemic diarrhea (PED) is characterized by acute villus atrophy and congestion, severe watery diarrhea, dehydration and death. PED can infect pigs of all ages and causes high mortality in newborn piglets (mortality rate is nearly 100%) (Li, et al, 2012; Zhang, et al, 2019). Its causative agent is porcine epidemic diarrhea virus (PEDV). PED has been reported in Asia since the 1980s, its prevalence has been comparatively low (Takahashi, et al, 1983; Puranaveja, et al, 2009; Lin, et al, 2014; Jung, et al, 2016; Sun, et al, 2016). Since late 2010, the new PED strains with high pathogenicity in China have been regarded as pandemic strains (Sun, et al, 2016).

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