Study Of Cryptoporms Volvatus On Anti-PRRSV Physiologically Active Substances And Hepatoprotective Effcect

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. The study had identified two new anti-PRRSV agents in the aqueous extract of C. volvatus, by employing a combination of modern chromatographic purification techniques and indirect immunofluorescence assay ?IFA?. As to the two anti-PRRSV agents,one was a novel compound, another was a new ribonuclease?RNases?. In addition, the study also found the protective effect of water-soluble extract from C. volvatus to CCl4-induced hepatic function impaired mice.By using HP-20, HP-2MGL, DEAE-cellulose, LH-20 and HPLC chromatography, a novel compound with PRRSV inhibitory activity was isolated from dry fruiting bodies of the mushroom C.volvatus in Vitro. Our results showed that C. volvatus extracts from every separation step differed in their inhibitory potency on PRRSV. One anti-PRRSV component designated as C_M-H-L-5 was isolated from water-soluble fraction of C. volvatus. The inhibition induced by C_M-H-L-5 occurred in a dose-dependent manner. C_M-H-L-5 inhibited the activity of PRRSV strain HV with an EC50 of 0.29mg/ml.C_M-H-L-5 appeared to be a low-molecular-weight polyol fragment with amide groups and carboxylic acid groups. The molecular weight of C_M-H-L-5 was 403.1Da. Collectively, our findings imply that C_M-H-L-5 from the aqueous extract of C. volvatus has the potential to be used for anti-PRRSV therapy.An anti-PRRSV RNases of 50kDa was isolated from dry fruiting bodies of the mushroom C.volvatus. It was purified by ion exchange chromatography on DEAE-cellulose, Q-sepharose and Mono Q, followed by fast protein liquid chromatography gel filtration on Superdex 75. The RNases with an optimum pH of 4 and an optimum temperature at 50?. The partial amino acid sequence was determined which showed homology to Penicillium oxalicum RNases to some degree. The RNase activity was suppressed by High concentration of Cd2+?10mM? or low concentration of Fe³⁺?1.25mM?ions. It exerted the highest RNase activity on tRNA. The RNase inhibited the activity of PRRSV strain HV with an EC50 of 0.25mg/ml.To explore the medicinal value of C. volvatus,the protective effects of water extract from C.volvatus to CCl4-induced hepatic function impaired mice were investigated. Mice were randomly assigned into five groups,namely normal control group,model group,positive control group,low-and high-dosage groups [0.4 and 0.8g/?kg·d?] of water extract from C. volvatus. Except the normal control group,all mice of the rest groups were induced with CC14 through intraperitoneal injection at a dosage of 10mg/kg. The water extract from C. volvatus could extremely significantly reduce activity of AST,ALT in mouse serum, content of MDA in mouse liver tissue and activity of T-SOD and GSH-PX in mouse liver tissue. Besides, the water extract could reduce the extent of necrosis of liver cells. The results suggested the protective effects of water extract from C. volvatus to CCl4-induced hepatic function impaired mice.