Epimedium polysaccharide and propolis flavone can synergistically inhibit the cellular infectivity of NDV and improve the curative effect of ND in chicken

Four prescriptions, epimedium flavone plus propolis flavone (EF-PF), epimedium flavone plus propolis extracts (EF-PE), epimedium polysaccharide plus propolis flavone (EP-PF) and epimedium polysaccharide plus propolis extracts (EP-PE), were prepared and their antiviral effects were compared. In test in vitro, the four prescriptions within safety concentration scope and Newcastle disease virus (NDV) were added into cultured chick embryo fibroblast (CEF) in three modes, pre-, post-adding drug and simultaneous-adding drug and virus after being mixed, the cellular A570 values were determined by MTT method and the highest virus inhibitory rates were calculated to compare the antiviral activity of four prescriptions. In test in vivo, three hundred 21-day-old chickens were randomly divided into 6 groups and challenged with NDV except for blank control group. After 24 h the chickens in four prescription groups were injected with corresponding drugs respectively, in virus control and blank control groups, with physiological saline, once a day for three successive days. On days 3, 7 and 14 after challenge, the serum antibody titer was determined. On day 15 after challenge, the mortality, morbidity and cure rate in every group were counted. The results showed that the most of A570 values in EP-PF group were numberly or significantly larger than those of the corresponding virus control group and the highest virus inhibitory rates of EP-PF at optimal concentration group were the highest among four prescription groups in three drug-adding modes, which confirmed that EP-PF could significantly inhibit the infectivity of NDV to CEF, its action was stronger than those of other three prescriptions; in EP-PF group, the antibody titers and cure rate were the highest and the mortality and morbidity were lowest presenting numberly or significantly differences in comparison with other three prescription groups. These results indicated that epimedium polysaccharide and propolis flavone possessed synergistical action, EP-PF prescription could significantly inhibit the cellular infectivity of NDV, improve the curative effect of ND in chicken and would be expected to exploit into a new-type antiviral drug.