<div style="text-align: justify;">This study was designed to investigate anti-virus action of the swainsonine (SW) extract of Astragalus strictus Grah. Ex Bend on bovine viral diarrhea virus (BVDV). Using cell culture techniques, and combining cytopathic effect (CPE) observation method and methyl thiazolyl tetrazolium (MTT) method to detect the toxicities of different concentrations of SW in bovine kidney primary cells (Madin-Darby Bovine Kidney Cells, MDBK), determine the drug safety concentration and TD50, Testing the comprehensive effect of different concentrations of SW for BVDV by adding swainsonine after virus-and-swainsonine added. The results showed that the TCID50 of BVDV is 10-4.7; there is no toxicity to MDBK when the concentration of SW below 0.256,mg&middot;mL-1, and TD50 is 2.512mg&middot;mL-1; Under the way of comprehensive action, IC50 is 0.782mg&middot;mL-1, TI is 3.21. it showed that the comprehensive effect on BVDV of SW (65.29%, P&lt;0.01) is good. The anti-BVDV effect of swainsonine in vitro is good and the antiviral mechanism of SW was speculated to SW inhibit the replication of BVDV proliferation or directly inactivate free BVDV.</div>

<div style="text-align: justify;">Study on the anti bovine viral diarrhea virus effect of swainsonine extract of <em>Astragalus strictus Grah Ex Bend in vitro</em></div>

Study on the anti bovine viral diarrhea virus effect of swainsonine extract of Astragalus strictus Grah Ex Bend in vitro