Significative Inactivation of SARS-CoV-2 3CL- Protease by Camellia sinensis Galloylated theaflavins: Processing conditions to maximize TF-3,3 -DG content

• Main Author: Paiva, Lisete
• Publication Date: 2022
• Other Authors: Rato, Catarina, Baptista, José
• Format: Article
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/10400.3/6967
• topic: Tea (C. sinensis) Flower; São Miguel Island (Azores); COVID-19

ABSTRACT: Since the last decade of the 19th century, the Camellia sinensis tea plant is commercially produced in one unique place in Europe, the volcanic São Miguel Island of the Azores Archipelago (Portugal) [1,2]. The molecular constituents of C. sinensis, in particular the galloylated theaflavins, mainly theaflavin-3,3’-di-O-gallate (TF-3,3’-DG), have been reported to inhibit SARS-CoV-2 3-chymotrypsin-like protease (3CLpro), a crucial enzyme required for the cleavage of its polyproteins (1a and 1ab) to produce vital individual functional proteins for viral cell replication [3]. According to Ohgitani [4] the virus treated with galloylated theaflavins, particularly TF-3,3’-DG, at 100 µM showed less than 1/10.000 infectivity compared to untreated virus. The TF-3,3’-DG content increased 50.91% with increased fermentation time from 1 to 3 hrs at room temperature (RT) and increased 41.26% at 35 °C of fermentation temperature. Furthermore, TF-3,3’-DG increased 29.40% with increasing temperature from RT to 70 °C in short extraction time (1:30 hrs) and oppositely decreased 18.44% with increasing temperature from RT to 70 °C in long extraction time (16:00 hrs). Taking all of the in vitro reported studies by several research teams and the in vivo results comparing the COVID-19 infections (mortality per million of population) in high tea consumption (4.28%) as compared with low tea consumption countries [5], the aim of this study was to investigate the steps of tea manufacturing conditions which lead to maximum TF-3,3’-DG content and, given its potential impact as an inhibitor of the 3CLpro enzyme, to create a novel antiviral Azorean black tea.