Inhibitory action and mechanism of matrine against porcine reproductive and respiratory syndrome virus in vitro

To observe the inhibitory action of matrine against PRRSV in vitro using visualization of cytopathologic effect(CPE) assay and MTT test on Marc-145 cell,and explores the mechanism by time-of-addition assay,adsorption inhibition assay and virucidal assay.The result shows that CC50 of matrine is larger than 1 500 mg/L.The maximum non-cytotoxic concentration(MNTC) and EC50 are nearly 750 mg/L and(443.5±33.4) mg/L separately,SI is greater than 3.8,the inhibition ratio of Matrine against PRRSV up to 93.6% in MNTC.The inhibition ratios separately are up to 105.10% and 91.53% in virucidal assay and the time-of-addition assay,lower than 20% of the inhibition ratios in the adsorption inhibition assay showes that matrine did not inhibite virus attach to Marc-145 cell.The experimental results demonstrates that matrine could reduce the damage of PRRSV to Marc-145 cell effectively.Its mechanism of antiviral actions could be due to inhibit the virus in the early or middle stage of replication or / and inactivate the virus directly,which suggests that matrine could be used for developing a new drug or precursor in treating and preventing porcine reproductive and respiratory syndrome.