□ Dr. Choi Jang-Gi’s research team (first author: Dr. Kim Young Soo) at the KM Application Center of the Korea Institute of Oriental Medicine (KIOM / President: Lee Jin-Yong) found a substance in mulberry twig, a herbal material, that effectively suppresses the infection of COVID-19 (SARS-CoV-2).

◦The outcome of the research was published in October issues of international academic journals Nutrients (IF 6.706) and International Journal of Molecular Sciences (IF 6.208). Prior to this, a technology transfer contract was signed in relation to the research result at KRW 180 million in advance royalty last May.

※ Paper title: Mulberrofuran G, a Mulberry Component, Prevents SARS-CoV-2 Infection by Blocking the Interaction between SARS-CoV-2 Spike Protein S1 Receptor-Binding Domain and Human Angiotensin -Converting Enzyme 2 Receptor

◦Mulberry twig known as Sang Zhi is young twig of mulberry tree that belongs to the Moraceae family in the Urticales order of Dicotyledon class. From the old days, mulberry tree was known for its high pharmaceutical values, and accordingly, its fruits, leaves, roots and branches all have been used as herbal materials.

□ The research team reported that components mulberrofuran G and kuwanon C of mulberry twig effectively blocked the penetration of COVID-19 into host cells of humans in the early stage of infection.

◦COVID-19 that has entered human body starts to penetrate cells through the binding of the spike protein on the surface of the virus and the ACE2 receptor of human epithelial cells.

◦Based on the analysis of molecular binding affinity, the research team reported that coupling of the two proteins was effectively blocked through strong binding of mulberrofuran G and kuwanon C with the spike protein and ACE2 receptor.

◦It also confirmed through cellular experiment that mulberrofuran G and kuwanon C were able to block COVID-19 in the early stage of infection by suppressing pseudovirus infection and actual virus infection.

□ COVID-19 medicines approved by the Food and Drug Administration (FDA) in the U.S. as of the present include small molecule-based virus RNA replication inhibitors such as remdesivir, molnupiravir and Paxlovid, as well as giant molecule-based cell entry inhibitors including antibodies.

◦ However, mutant viruses resistant to RNA replication inhibitors remdesivir and Paxlovid have already appeared, and antibody-based drugs have limitations because they require intravenous injection administered in hospitals.

□ Dr. Choi Jang-Gi who led the research said, “As coronavirus that genetically has RNA is subject to frequent mutations, drug-resistant viruses are highly likely to appear. It is expected that mulberrofuran G and kuwanona C, whose potential as cell entry inhibitors has been confirmed in the research, will improve the COVID-19 cure rate through combined application with existing RNA replication inhibitors, while also suppressing the occurrence of drug-resistant viruses.”

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