The rapid spread of novel coronavirus called SARS-CoV-2 or nCoV has caused countries all over the world to impose lockdowns and undertake stringent preventive measures. This new positive-sense single-stranded RNA strain of coronavirus spreads through droplets of saliva and nasal discharge.
Purpose
US FDA has authorized the emergency use of Remdesivir looking at the increasing number of cases of COVID-19, however there is still no drug approved to treat COVID-19. An alternative way of treatment could be the use of naturally derived molecules with known antiviral properties.
Method
We reviewed the antiviral activities of two polyphenols derived from tea, epigallocatechin-3-gallate (EGCG) from green tea and theaflavins from black tea. Both green tea and black tea polyphenols have been reported to exhibit antiviral activities against various viruses, especially positive-sense single-stranded RNA viruses.
Results
Recent studies have revealed the possible binding sites present on SARS-CoV-2 and studied their interactions with tea polyphenols. EGCG and theaflavins, especially theaflavin-3,3′-digallate (TF3) have shown a significant interaction with the receptors under consideration in this review. Some docking studies further emphasize on the activity of these polyphenols against COVID-19.
Conclusion
This review summarizes the available reports and evidences which support the use of tea polyphenols as potential candidates in prophylaxis and treatment of COVID-19.
Graphical abstract
Keywords
COVID-19
SARS-CoV-2
Tea polyphenols
EGCG
Theaflavin
Abbreviations
2′-O-MTase
2′-O-methyltransferase
3CLpro
Chymotrypsin-like protease
ACE2
Angiotensin-converting enzyme 2
CTD
C-terminal domain
E
Envelope protein
EGCG
Epigallocatechin Gallate
GRP78
Glucose-regulated Proteins
HCV
Hepatitis C virus
HE
Hemagglutinin Esterase
HIV
Human immunodeficiency virus
M
Membrane protein
MERS-CoV
Middle East Respiratory Syndrome Coronavirus
Mpro
Main protease
N
Nucleocapsid protein
Nsp
Non-structural proteins
NTD
N-terminal domain
PLpro
Papain like protease
PRRSV
Porcine reproductive and respiratory syndrome virus