Curcumol Inhibits Encephalomyocarditis Virus by Promoting IFN-β Secretion

Background: EMCV infection can cause reproductive failure in sows and acute myocarditis and sudden death in piglets. It has caused huge economic losses to the global pig industry. It is necessary to develop effective new compounds. Traditional Chinese medicine zedoary turmeric oil can be used for treating myocarditis caused by EMCV infection. Curcumol extracted from the roots of Curcuma is one of the main active ingredient of zedoary turmeric oil. To investigate whether curcumol has antiviral activity again the EMCV infection, and what are the molecular mechanisms of such antiviral activity with a focus on the IFN-β signaling pathway. Method: MTT assay was used to determine the maximum non-toxic concentration (MNTC), 50% cytotoxic concentration (CC 50 ), maximum inhibition rate (MIR) and 50% effective concentration (EC 50 ) against EMCV. Through EMCV load, the anti-viral effect of curcumol was quantitatively determined using real-time quantitative PCR. The effect of curcumol on the expression of IFN-β was checked using real-time quantitative PCR and ELISA. Western blot was used to determine the amounts of MDA5, MAVS, TANK, IRF3 and P-IRF3 proteins in HEK-293T cells infected with EMCV. Results: The results showed that compared with the positive drug ribavirin control, the MIR of curcumol was greater but the SI value was much smaller than that of ribavirin. The curcumol at 25 μg/ml has significant anti-EMCV activities and increased the expression of IFN-β ( P < 0.05). The curcumol inhibited the degradation of TANK protein mediated by EMCV and promoted the expression of MDA5 and P-IRF3, while the protein expression level of MAVS and IRF3 remain unchanged. Conclusion: Curcumol has biological activity against EMCV which we suggest that IFN-β signaling pathway is one of its mechanisms, providing new ideas for clinical treatment of EMCV infection.