{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,10]],"date-time":"2026-09-10T10:09:55Z","timestamp":1789034995760,"version":"build-2803163510"},"reference-count":38,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,9,10]],"date-time":"2026-09-10T00:00:00Z","timestamp":1788998400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Key Research and Development Program of Jilin Provincial Department of Science and Technology","award":["20230202088NC"],"award-info":[{"award-number":["20230202088NC"]}]},{"award":["20230202088NC"],"award-info":[{"award-number":["20230202088NC"]}],"id":[{"id":"https:\/\/ror.org\/049x38272","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Viruses"],"abstract":"<jats:p>Porcine epidemic diarrhea virus (PEDV) variant strains lead to vaccine failures and significant economic losses in swine farming, highlighting the need for new natural small-molecule antiviral candidates. In this study, we screened a library of 45 small molecules using a cytopathic effect (CPE)-based cytoprotective assay. Saikosaponin B2 (SSB2), a triterpenoid saponin derived from Bupleuri Radix, emerged as the most promising candidate, boasting a selectivity index of 19.77, which surpasses that of most natural compounds. Dose\u2013response tests confirmed SSB2\u2019s concentration-dependent anti-PEDV activity, with an inhibitory plateau reached at concentrations above 60 \u03bcmol\/L (\u03bcM). The 50 half-maximal effective concentration (EC50) values differed between CPE reduction and viral titer readouts, a discrepancy commonly due to varying detection sensitivities. Mechanistic assays revealed that SSB2 does not possess direct virucidal properties; instead, its antiviral efficacy depends on sustained treatment to inhibit viral adsorption and internalization. Time-of-addition experiments further demonstrated that SSB2 effectively suppresses both early viral entry and mid-stage intracellular genome replication, without affecting viral release. Notably, post-infection treatment resulted in stronger inhibition compared to continuous administration, possibly due to disrupted cellular proliferation homeostasis from prolonged exposure. Additionally, SSB2 maintained strong inhibitory effects against prevalent G2a (JL-06) and G2b (JL-08) field variants, though its efficacy was reduced for both strains and slightly weaker against JL-08 than JL-06. Overall, this study systematically characterizes SSB2\u2019s dual-stage anti-PEDV profile and its broad-spectrum activity against spike-mutant strains, supporting SSB2 as a promising herbal lead for developing veterinary antivirals targeting variant PEDV.<\/jats:p>","DOI":"10.3390\/v18090997","type":"journal-article","created":{"date-parts":[[2026,9,10]],"date-time":"2026-09-10T09:13:03Z","timestamp":1789031583000},"page":"997","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["In Vitro Assessment of Antiviral Activity of Saikosaponin B2 Against Porcine Epidemic Diarrheal Virus"],"prefix":"10.3390","volume":"18","author":[{"given":"Han","family":"Zhang","sequence":"first","affiliation":[{"name":"College of Animal Science and Technology, Jilin Agricultural Science and Technology College, Jilin 132101, China"},{"name":"College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"}]},{"given":"Yue","family":"Liu","sequence":"additional","affiliation":[{"name":"College of Animal Science and Technology, Jilin Agricultural Science and Technology College, Jilin 132101, China"},{"name":"College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"software","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"}]},{"given":"Fan","family":"Zhang","sequence":"additional","affiliation":[{"name":"College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"validation","vocabulary":"credit"}]},{"given":"Yibo","family":"Xu","sequence":"additional","affiliation":[{"name":"College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wanli","family":"Sha","sequence":"additional","affiliation":[{"name":"College of Animal Science and Technology, Jilin Agricultural Science and Technology College, Jilin 132101, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-4463-1154","authenticated-orcid":false,"given":"Shushuai","family":"Yi","sequence":"additional","affiliation":[{"name":"College of Animal Science and Technology, Jilin Agricultural Science and Technology College, Jilin 132101, China"},{"name":"Jilin Province Cross Regional Cooperation Technology Innovation Center of Porcine Main Disease Prevention and Control, Jilin 132101, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"}]},{"given":"Baishuang","family":"Yin","sequence":"additional","affiliation":[{"name":"College of Animal Science and Technology, Jilin Agricultural Science and Technology College, Jilin 132101, China"},{"name":"Jilin Province Cross Regional Cooperation Technology Innovation Center of Porcine Main Disease Prevention and Control, Jilin 132101, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"msad052","DOI":"10.1093\/molbev\/msad052","article-title":"Global Dynamics of Porcine Enteric Coronavirus PEDV Epidemiology, Evolution, and Transmission","volume":"40","author":"Zhang","year":"2023","journal-title":"Mol. 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