Tea as a natural gift for discovering antiviral candidates

Coronavirus disease (COVID-19) remains rampant worldwide and poses a serious threat to human health. Tea is a medicinal and edible homologous plant that exhibits potential anti-SARS-CoV-2 properties via the prevention of virus entry into host cells, inhibition of virus replication, and enhancement of the innate and cellular immune responses. In this review, the properties of six major types of tea were systematically summarized, including green tea, yellow tea, white tea, oolong tea, black tea, and dark tea. We focused on the primary components of tea exhibiting antiviral activities, which included (–)-epigallocatechin-3-gallate, (–)-gallocatechin gallate, tannic acid, oolonghomobisflavan A, theaflavins, and white-tip silver needle flavonoids. Among them, (–)-epigallocatechin-3-gallate is proposed to be an antiviral compound that interferes with the entire life cycle of SARS-CoV-2 by balancing inflammation and immunity. Thus, this compound can serve as a promising lead structure for the development of SARS-CoV-2 inhibitors. Graphical abstract: http://links.lww.com/AHM/A39.