□ The Korea Institute of Oriental Medicine (KIOM / President: Lee Jin-Yong) announced that the research team led by Dr. Ma Jin Yeul (first author: Dr. Cho Won-Kyung) at its KM Application Center had verified strong suppressive effect of an ingredient derived from lotus leaf on influenza viruses.

◦The outcome of the research was published in the October issue of International Journal of Molecular Sciences (IF 6.208), a leading international academic journal.

※ Paper title: Antiviral Effect of Isoquercitrin against Influenza A Viral Infection via Modulating Hemagglutinin and Neuraminidase

□ In a previous study, the research team confirmed antiviral effect of lotus leaf extract in suppressing neuraminidase and hemagglutinin, proteins essential for infection and proliferation of influenza viruses.

※ Neuraminidase (NA) is a protein required when influenza viruses replicate and proliferate within cells after initial infection, break out of the cells and spread to neighboring cells.

※ Hemagglutinin (HA) is a protein essential for influenza viruses to attach to and penetrate cells in the early stage of infection.

◦The result of the previous study was published in the Journal of Functional Foods, a leading international academic journal, in March 2022, and a relevant patent application has already been made.

◦The research team confirmed that the ingredient directly affecting the antiviral effect of lotus leaf extract is isoquercitrin.

※ Isoquercitrin is a flavonoid contained in various natural products including lotus leaf, and it has been reported to have antiviral effect against a variety of viruses such as Zika virus, Ebola virus, and herpes virus.

□ It has been known that lotus leaf has various effects such as antioxidant effect, anticancer effect, anti-inflammatory effect, anti-obesity effect, and liver protection effect.

◦However, its is the first research that shows the key role of isoquercitrin, a component of lotus leaf extract, in antiviral effect, in addition to the suppressive effect of lotus leaf on influenza viruses.

□ In the research, isoquercitrin was found to have outstanding virus treatment effect by inhibiting the cell attachment and penetration of influenza viruses even at low concentrations, killing viruses directly, and suppressing viruses also when they have proliferated and got discharged from cells.

□ Dr. Ma Jin Yeul, the team leader said, “At present, Tamiflu is mainly used to treat influenza, but it has problems regarding the emergence of drug-resistant viruses and adverse effects. In the future, we plan to examine the antiviral effect on influenza viruses resistant to Tamiflu and test the effect on animal models.”

□ The research was conducted as part of the key programs of KIOM, an affiliate of the Ministry of Science and ICT, and under the support of the basic research program by individual researchers of the National Research Foundation of Korea.