{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,9]],"date-time":"2026-10-09T15:23:32Z","timestamp":1791559412701,"version":"4.3.4"},"reference-count":49,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2023,1,21]],"date-time":"2023-01-21T00:00:00Z","timestamp":1674259200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the Ministry of Science and Technology, Taiwan","award":["MOST 111-2321-B-005-006"],"award-info":[{"award-number":["MOST 111-2321-B-005-006"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Theacrine and strictinin of Yunnan Kucha tea prepared from a mutant variety of wild Pu\u2019er tea plants were two major ingredients responsible for the anti-influenza activity. As the COVID-19 outbreak is still lurking, developing safe and cost-effective therapeutics is an urgent need. This study aimed to evaluate the effects of these tea compounds on the infection of mouse hepatitis virus (MHV), a \u03b2-coronavirus serving as a surrogate for SARS-CoV. Treatment with strictinin (100 \u03bcM), but not theacrine, completely eliminated MHV infection, as indicated by a pronounced reduction in plaque formation, nucleocapsid protein expression, and progeny production of MHV. Subsequently, a time-of-drug addition protocol, including pre-, co-, or post-treatment, was exploited to further evaluate the possible mechanism of antiviral activity mediated by strictinin, and remdesivir, a potential drug for the treatment of SARS-CoV-2, was used as a positive control against MHV infection. The results showed that all three treatments of remdesivir (20 \u03bcM) completely blocked MHV infection. In contrast, no significant effect on MHV infection was observed when cells were pre-treated with strictinin (100 \u03bcM) prior to infection, while significant inhibition of MHV infection was observed when strictinin was introduced upon viral adsorption (co-treatment) and after viral entry (post-treatment). Of note, as compared with the co-treatment group, the inhibitory effect of strictinin was more striking in the post-treatment group. These results indicate that strictinin suppresses MHV infection by multiple mechanisms; it possibly interferes with viral entry and also critical step(s) of viral infection. Evidently, strictinin significantly inhibited MHV infection and might be a suitable ingredient for protection against coronavirus infection.<\/jats:p>","DOI":"10.3390\/molecules28031080","type":"journal-article","created":{"date-parts":[[2023,1,23]],"date-time":"2023-01-23T01:36:26Z","timestamp":1674437786000},"page":"1080","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["Strictinin, a Major Ingredient in Yunnan Kucha Tea Possessing Inhibitory Activity on the Infection of Mouse Hepatitis Virus to Mouse L Cells"],"prefix":"10.3390","volume":"28","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4665-876X","authenticated-orcid":false,"given":"Erh-Chuang","family":"Tu","sequence":"first","affiliation":[{"name":"Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung 402, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1392-163X","authenticated-orcid":false,"given":"Wei-Li","family":"Hsu","sequence":"additional","affiliation":[{"name":"Graduate Institute of Microbiology and Public Health, National Chung-Hsing University, Taichung 402, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4218-6363","authenticated-orcid":false,"given":"Jason T. C.","family":"Tzen","sequence":"additional","affiliation":[{"name":"Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung 402, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,1,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"628","DOI":"10.1093\/ije\/dyh198","article-title":"Severe acute respiratory syndrome: Review and lessons of the 2003 outbreak","volume":"33","author":"Parashar","year":"2004","journal-title":"Int. J. Epidemiol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"44","DOI":"10.1016\/j.ijid.2020.03.004","article-title":"The SARS-CoV-2 outbreak: What we know","volume":"94","author":"Wu","year":"2020","journal-title":"Int. J. Infect. 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