Influenza infection and associated epidemics represent a serious public health
problem. Several preventive and curative measures exist against its spread including vaccination
and therapeutic agents such as neuraminidase inhibitors (e.g., oseltamivir, zanamivir,
as well as peramivir and laninamivir, which are licensed in several countries) and adamantanes
(e.g., amantadine and rimantadine). However, neuraminidase inhibitor- and adamantane-
resistant viruses have been detected, whereas vaccines exhibit strain-specific effects
and are limited in supply. Thus, new approaches are needed to prevent and treat influenza
infections. Catechins, a class of polyphenolic flavonoids present in tea leaves, have been reported
as potential anti-influenza virus agents based on experimental and clinical studies.
(−)-epigallocatechin gallate (EGCG), a major and highly bioactive catechin, is known to inhibit
influenza A and B virus infections in Madin-Darby canine kidney cells. Additionally,
EGCG and other catechin compounds such as epicatechin gallate and catechin-5-gallate also
show neuraminidase inhibitory activities as demonstrated via molecular docking. These
catechins can bind differently to neuraminidase and might overcome known drug resistancerelated
virus mutations. Furthermore, the antiviral effects of chemically modified catechin
derivatives have also been investigated, and future structure-based drug design studies of
catechin derivatives might contribute to improvements in influenza prevention and treatment.
This review briefly summarizes probable mechanisms underlying the inhibitory effects
of tea catechins against influenza infection and their clinical benefits on influenza prevention
and treatment. Additionally, the great potential of tea catechins and their chemical
derivatives as effective antiviral agents is described.