Evaluation of green tea extract as a safe personal hygiene against viral infections

Lee, Yun Ha; Jang, Yo Han; Kim, Young-Seok; Kim, Jinku; Seong, Baik Lin

We further examined whether the addition of supplements (citric acid, sodium benzoate, and ascorbic acid) influenced the chemical stability of green tea catechins that were known to exert the antiviral activity. GTE and GTE-mix solutions were stored at 25°C for up to 56 days, and the concentrations of catechins in the solutions were determined by GC/MS analysis. The catechins were stably maintained regardless of the presence of the supplements (Fig. 4a) , showing that the addition of the supplements did not affect the catechins stability in the GTE solution. Next, we monitored the kinetics of viral inactivation of GTE in the presence of the supplements. Based on the result in Fig. 3a , we further compared the inactivation kinetics between GTE and GTE-mix solutions. 0.1% of GTE and GTE-mix solutions were stored at 25°C for 1 day, and the solutions were then further incubated with 10 6 PFU of PR8 virus at 25°C for 0-360 min for viral inactivation. The viral titers in the mixtures taken at different time-points were determined by plaque assay to observe the kinetics of time-dependent viral inactivation. Viral inactivation by GTE solution was rapid, resulting in greater than 4 log 10 reduction of viral titers within five mins after the incubation, and a complete inactivation was achieved after 120 mins after the incubation (Fig. 4b) . On the other hand, GTE-mix solution resulted in only 1 log 10reduction of the viral titers within 30 mins, and complete inactivation was achieved after 360 mins of the incubation (Fig. 4b) , clearly showing that supplements added to the GTE solution interfered with catechinmediated viral inactivation. Taken together, the addition of the supplements to GTE solution resulted in the delay of the exhaustion of the inactivating activity of GTE, thus enabling a long-term maintenance of its antiviral function.