Anti-SARS-CoV-2 activity of various PET-bottled Japanese green teas and tea compounds in vitro

Abstract

The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a serious threat to global public health. The emergence of SARS-CoV-2 variants is a significant concern regarding the continued effectiveness of vaccines and antiviral therapeutics. Thus, natural products such as foods, drinks, and other compounds should be investigated for their potential to treat COVID-19. Here, we examined the in vitro antiviral activity against SARS-CoV-2 of various polyethylene terephthalate (PET)-bottled green Japanese teas and tea compounds. Six types of PET-bottled green tea were shown to inhibit SARS-CoV-2 at half-maximal inhibitory concentrations (IC 50 ) of 121- to 323-fold dilution. Our study revealed for the first time that a variety of PET-bottled Japanese green tea drinks inhibit SARS-CoV-2 infection in a dilution-dependent manner. The tea compounds epigallocatechin gallate (EGCG) and epicatechin gallate showed virucidal activity against SARS-CoV-2, with IC 50 values of 6.5 and 12.5 µM, respectively. The investigated teas and tea compounds inactivated SARS-CoV-2 in a dose-dependent manner, as demonstrated by the viral RNA levels and infectious titers. Furthermore, the green teas and EGCG showed significant inhibition at the entry and post-entry stages of the viral life cycle and inhibited the activity of the SARS-CoV-2 3CL-protease. These findings indicate that green tea drinks and tea compounds are potentially useful in prophylaxis and COVID-19 treatment. Supplementary Information The online version contains supplementary material available at 10.1007/s00705-022-05483-x.

Potential of green tea EGCG in neutralizing SARS-CoV-2 Omicron variant with greater tropism toward the upper respiratory tract

“… The IC 50 of EGCG for virus replication was 6.5 μM and the virus replication was almost fully inhibited by EGCG at a dose of 50 μM, which had no cytotoxicity. Ngwe Tun et al (2022) Treatment with 25 and 50 μM EGCG resulted in 95% and over 99.9% decrease of virus titers, respectively. Viral N protein expression was almost completely suppressed by the treatment with 50 μM EGCG.…”

“…Ngwe Tun et al examined the effect of full EGCG treatment, in which EGCG was present throughout all in vitro experimental procedures, on SARS-CoV-2 replication ( Ngwe Tun et al, 2022 ). Specifically, Vero E6 cells were pre-treated with EGCG for 1 h prior to viral infection, and then were infected with SARS-CoV-2 for 2 h. After the supernatant containing virus and EGCG was removed, the cells were washed with phosphate buffered saline.…”

Green Tea Consumption and the COVID-19 Omicron Pandemic Era: Pharmacology and Epidemiology

“…Among these, there was mounting evidence suggesting the therapeutic potential of green tea catechins in the prevention/treatment of COVID-19. We and other groups identified green tea extract and the active ingredients of green tea, EGCG and theaflavin, as inhibitors of the SARS-CoV-2 3CL protease necessary for viral reproduction [ 10 , 11 , 12 , 13 , 14 ]. Furthermore, EGCG or green tea extract treatment reduced infection of SARS-CoV-2 as well as other human beta coronaviruses in human and primate cells [ 14 , 15 , 16 , 17 , 18 ], and reduced the viral load in the lung tissue of mice [ 17 ].…”

COVID-19 and per capitagreen tea consumption: update

“…There is mounting evidence suggesting the therapeutic potential of green tea catechins in prevention/treatment of COVID19. In particular, in addition to numerous docking studies (for instance, [1][2][3][4][5][6][7]) there is growing number of studies showing direct antiviral activity of at least one catechin epigallocatechin-3-gallate (EGCG) against SARS-CoV-2 in in vitro experiments ( [8][9][10][11][12][13][14][15][16][17] see also [18][19][20] for review). Moreover, a recent work [21] reports that EGCG from green tea effectively blocks infection of SARS-CoV-2 and new variants.…”