Rahmi Dianty^1,2 , Junki Hirano^1,2 , Itsuki Anzai^1,3 , Yuta Kanai^1,4 , Tsuyoshi Hayashi⁵ , Masae Morimoto⁶ , Chikako Kataoka-Nakamura⁶ , Sakura Kobayashi⁵ , Kentaro Uemura^1,2 , Chikako Ono^1,2 , Tokiko Watanabe^1,3,7 , Takeshi Kobayashi^1,4,7 , Kosuke Murakami⁵ , Kenji Kikuchi⁸ , Kunimoto Hotta⁸ , Toshikazu Yoshikawa⁸ , Shuhei Taguwa^{1,2,7 *} and Yoshiharu Matsuura^{1,2,7 *}

¹ Laboratory of Virus Control, Center for Infectious Disease Education and Research, Osaka University, Osaka, Japan, 2Laboratory of Virus Control, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan, 3Laboratory of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan, 4Laboratory of Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan, 5Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan, 6Innovative Vaccine Research and Development Center, The Research Foundation for Microbial Diseases of Osaka University, Osaka, Japan, 7 Center for Advanced Modalities and DDS, Osaka University, Osaka, Japan, 8Louis Pasteur Center for Medical Research, Kyoto, Japan

It is essential to employ efficient measures to prevent the transmission of pathogenic agents during a pandemic. One such method involves using hypochlorous acid (HClO) solution. The oxidative properties of HClO water (HAW) can contribute to its ability to eliminate viral particles. Here, we examined a highly purified slightly acidic hypochlorous acid water (Hp-SA-HAW) obtained from the reverse osmosis membrane treatment of an electrolytically-generated SA-HAW for its anti-viral activity and mode of action on viral proteins. Hp-SA-HAW exhibited broad-spectrum antiviral effects against various viruses, including adenovirus, hepatitis B virus, Japanese encephalitis virus (JEV), and rotavirus. Additionally, Hp-SA-HAW treatment dose-dependently resulted in irreversibly aggregated multimers of the JEV envelope and capsid proteins. However, Hp-SA-HAW treatment had no discernible effect on viral RNA, indicating that Hp-SA HAW acts against amino acids rather than nucleic acids. Furthermore, Hp-SA-HAW substantially reduced the infectivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including the ancestral variant and other multiple variants. Hp-SA-HAW treatment induced the aggregation of the SARS-CoV-2 spike and nuclear proteins and disrupted the binding of the purified spike protein of SARS-CoV-2 to human ACE2. This study demonstrates that the broad-spectrum virucidal activity of highly purified HClO is attributed to viral protein aggregation of virion via protein oxidation.

KEYWORDS

hypochlorous acid, virucide, SARS-CoV-2, oxidation, protein aggregation