In vitro anti-respiratory syncytial virus effect of an active compound (AP4) from Herba patriniae

Objective: To investigate the in vitro inhibition of respiratory syncytial virus by an active compound (AP4) from a Chinese medicine herb--Herba patriniae. Methods: Active component of herba patriniae (AP4 ) was extracted and its anti- respiratory syncytial virus effect was tested .A water soluble substance (AP4 ) was isolated from Herba patriniae,by hot water extraction ,ethanol precipitation and macroporous adsorptive resins adsorption.Chemical tests showed that the substance was polysaccharide. AP4 was active against the respiratory syncytial virus by CPEI assay while Ribavirin was used as positive control . Results: Chemical tests showed that the substance was polysaccharide. The median toxic concentration(TC_ 50 ) of AP4 was 11.07 mg/ml by morphological observation under light microscope , the medium effective concentration(EC_ 50 ) against replication of the long strain of respiratory syncytial virus in Hela cells was 0.097 mg/ml and therapeutic index(TI= TC_ 50 / EC_ 50 ) of AP4 was114.The median toxic concentration(TC_ 50 ) of ribavirin was 2.087 mg/ml, its medium effective concentration(EC_ 50 ) was 0.0385mg/ml and therapeutic index(TI= TC_ 50 / EC_ 50 ) of Ribavirin was 54.Conclusion: AP4 has an obvious inhibitor effect on RSV in Hela cell culture .