{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,9]],"date-time":"2026-05-09T16:04:52Z","timestamp":1778342692804,"version":"3.51.4"},"reference-count":19,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2024,11,4]],"date-time":"2024-11-04T00:00:00Z","timestamp":1730678400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"NSFC-MFST project (China\u2013Mongolia)","award":["32161143027"],"award-info":[{"award-number":["32161143027"]}]},{"name":"NSFC-MFST project (China\u2013Mongolia)","award":["SKLPBS2250"],"award-info":[{"award-number":["SKLPBS2250"]}]},{"name":"Foundation of State Key Laboratory of Pathogen and Biosecurity","award":["32161143027"],"award-info":[{"award-number":["32161143027"]}]},{"name":"Foundation of State Key Laboratory of Pathogen and Biosecurity","award":["SKLPBS2250"],"award-info":[{"award-number":["SKLPBS2250"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Studies have demonstrated that methylene blue exhibits significant antiviral activity against SARS-CoV-2 or related coronaviruses at the cellular level, suggesting its potential as an anti-SARS-CoV-2 drug. Herein, we report that methylene blue does not exhibit noticeable antiviral activity in a lethal model involving SARS-CoV-2-related pangolin coronavirus GX_P2V (short_3UTR) infection in CAG-hACE2 transgenic mice. We employed plaque reduction assays and cell infection experiments to compare the extracellular virucidal activity of the compound and its ability to inhibit viral replication in cells to those of nirmatrelvir. Methylene blue demonstrated strong virucidal activity but did not inhibit viral replication in cells. The control compound nirmatrelvir lacked virucidal activity but exhibited strong abilities to inhibit viral replication. The virucidal activity of methylene blue was further tested in mouse plasma. Incubation in mouse plasma increased the virucidal EC50 value of methylene blue, indicating that mouse plasma can affect the stability of the compound, although mouse plasma has some extent of natural virucidal activity. These findings elucidate why methylene blue lacks antiviral efficacy in vivo and provide insights for the development of antiviral drugs.<\/jats:p>","DOI":"10.3390\/pathogens13110958","type":"journal-article","created":{"date-parts":[[2024,11,5]],"date-time":"2024-11-05T08:25:14Z","timestamp":1730795114000},"page":"958","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Methylene Blue Has Strong Extracellular Virucidal Activity Against a SARS-CoV-2-Related Pangolin Coronavirus with No Intracellular or In Vivo Efficacy"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-1866-5241","authenticated-orcid":false,"given":"Lai","family":"Wei","sequence":"first","affiliation":[{"name":"College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100089, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuezhen","family":"Ma","sequence":"additional","affiliation":[{"name":"College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100089, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuhao","family":"Ren","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences (AMMS), Beijing 100071, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shanshan","family":"Lu","sequence":"additional","affiliation":[{"name":"College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100089, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xiumei","family":"Xiao","sequence":"additional","affiliation":[{"name":"The Department of Laboratory Medicine, Peking University Third Hospital, Beijing 100191, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shengdong","family":"Luo","sequence":"additional","affiliation":[{"name":"Institute of Infectious Diseases Medicine, The Fifth Medical Center of PLA General Hospital, Beijing 100039, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xiaoping","family":"An","sequence":"additional","affiliation":[{"name":"College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100089, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3065-1336","authenticated-orcid":false,"given":"Erguang","family":"Li","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Pharmaceutical Biotechnology, Medical School, Nanjing University, Nanjing 210093, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5007-2158","authenticated-orcid":false,"given":"Huahao","family":"Fan","sequence":"additional","affiliation":[{"name":"College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100089, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7299-5719","authenticated-orcid":false,"given":"Lihua","family":"Song","sequence":"additional","affiliation":[{"name":"College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100089, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,11,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1111\/j.1423-0410.1991.tb00907.x","article-title":"Photoinactivation of viruses in human fresh plasma by phenothiazine dyes in combination with visible light","volume":"60","author":"Lambrecht","year":"1991","journal-title":"Vox Sang."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2059","DOI":"10.1002\/jmv.25538","article-title":"Inactivation of Zika virus in plasma and derivatives by four different methods","volume":"91","author":"Wang","year":"2019","journal-title":"J. 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