Green Tea Catechins: Role as Antiviral Agents

Abstract

Green Tea Catechins (GTCs) - unarguably the wonder compounds with numerous medicinal properties and health benefits. And most importantly, these benefits include antiviral effects, so significant nowadays in our corona-hit world. The major catechins of green tea are four - epigallocatechin gallate (EGCG), epigallocatechin, epicatechin, and epicatechin-gallate. While each one of these has its own unique properties, EGCG, as per different studies, has been reported to be the most effective catechin showing significant antiviral activity against a broad spectrum of human and animal viruses. The antiviral properties of green tea extracts are manifold and target different areas. These include direct inactivation of the virus particles, prevention of entry into the target cell, inhibition of gene expression, inhibition of protein expression, inhibition of intestinal α-glycosidases that are important for processing glyco-conjugates of viruses, and lowering of proliferation of virus. Furtehrmore, a positive correlation between the antioxidant effects of catechins and their antiviral activities has been suggested. The growing concern about our health and the persistent fight while we are amidst the present coronavirus pandemic makes the inhibitory effect of GTCs a promising area of research. Due to their “relief and rectification” properties, these may be considered as a food supplement to ameliorate the harmful and deadly effects of the virus. The bioavailability of these polyphenols has been shown to be influenced by factors such as temperature, food processing methods, food matrix, and interaction with other compounds. Furthermore, the hydrophilic nature of EGCG molecule limits its bioavailability at the site of action. However, this limitation can be overcome and bioavailability of GTCs can be increased by chemical interventions, such as attachment of fatty acids. These ensure wide availability, and even wider use. The leading objective of this review is to collate, summarize and explain the information available on GTCs, and their effect on various pathogenic viruses in humans and animals. The GTCs surely promise to be an important weapon in our armour to fight corona and other pathogens.