A Novel Compound from the Mushroom Cryptoporus volvatus Inhibits Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) In Vitro

Porcine reproductive and respiratory syndrome (PRRS), caused by PRRS virus (PRRSV), is a serious contagious disease in the swine industry. At present, there are no effective control strategies against PRRSV. Thus, there is an urgent need for new treatment regimens that have efficacious antiviral activity to compensate for vaccines. The anti-infective effect of Cryptoporus volvatus has previously been demonstrated in Tradational Chinese Medicine. In this report, we expected to identify a new anti-PRRSV agent in the aqueous extract of C. volvatus, by employing a combination of modern chromatographic purification techniques and indirect immunofluorescence assay (IFA). Our results showed that C. volvatus extracts from every separation step differed in their inhibitory potency on PRRSV. One anti-PRRSV component designated as CM-H-L-5 was isolated from water-soluble fraction of C. volvatus. The inhibition induced by CM-H-L-5 occurred in a dose-dependent manner. CM-H-L-5 appeared to be a low-molecular-weight polyol fragment with amide groups and carboxylic acid groups. Collectively, our findings imply that CM-H-L-5 from the aqueous extract of C. volvatus has the potential to be used for anti-PRRSV therapy.