Norovirus is the world-leading cause of acute gastroenteritis associated with severe symptoms and deaths. However, vaccines against norovirus are currently not available, and medications that specifically target human norovirus infection are still under development. The current study evaluated the suitability of EC16, EGCG, and LTP for virucidal formulations (based on auto-oxidation), and used a murine norovirus (MNV S99, a human norovirus surrogate) cell infection system to evaluate the virucidal activity of EC16 sanitizer formulations, and as a treatment and prevention model to examine in vitro the antiviral activity of EC16 in comparison to EGCG.
Initially, formulation suitability tests were conducted to compare EGCG (epigallocatechin-3-gallate),
EC16 and tea polyphenol-palmitate in alcohol solution and hand hygiene formulations. The virucidal activity of EC16 was then tested in hand sanitizer gel and hand sanitizer foam formulations using a TCID50 time-kill suspension assay. In vitro treatment and prevention tests were performed using a 1-hour incubation of EC16 or EGCG with RAW264.7 cells, either pre-infection or post-infection with MNV. Statistical analysis employed the two-tailed student t test (alpha=0.05)
Here we report, for the first time, that the antiviral activity of EC16 could be used in prevention and treatment of norovirus infection, pending future proof-of-concept in vitro and in vivo studies prior to
human trials. In addition, the virucidal property of EC16 is suitable for use in hand hygiene and disinfectant products. It was also found that EGCG has lower antiviral activity comparing to EC16, and it is not suitable for virucidal formulations due to rapid auto-oxidation.