OBJECTIVE: To study the extraction of an active component LC-4 from Forsythia suspensa (Thunb.) Vahl and anti-respiratory syncytial virus (RSV) effect in vitro. METHODS: The extration from boiling water of Forsythia suspensa were extracted by hot water extraction and were precipitated by ethanol and were elicited by macroporous adsorptive resins column chromatography. Then the antiviral active component LC-4 was separated from the production by eluting. The cytotoxicities and antiviral effect of LC-4 were tested by the Neutral Red assay and the cytopathic effect (CPE) inhibition assay. Ribavirin was used as the positive drug in the study. The antiviral effect of prevention and treatment of maximum dose of non-cytotoxicity of LC-4 was tested in Hela cell line. RESULTS: LC-4 showed that the concentration were 25.4 microg/ml with the medium cytotoxicity and were 2.11 microg/ml with the medium effective concentration (EC50). The corresponding treatment index of LC-4 was 12.04. It also exhibited obviously inhibition effect on RSV replications when LC-4 was added at 2 h, 4 h, 6 h and 8 h after infection (P < 0.05). The CPE was significant difference in comparison with control group, when the concentration of LC-4 between 31.25 microg/ml and 3.91 microg/ml was added at 2 h before infection (P < 0.05). CONCLUSION: LC-4 could significantly prevent and inhibit RSV replications in vitro.
OBJECTIVE: To study the extraction of an active component LC-4 from Forsythia suspensa (Thunb.) Vahl and anti-respiratory syncytial virus (RSV) effect in vitro. METHODS: The extration from boiling water of Forsythia suspensa were extracted by hot water extraction and were precipitated by ethanol and were elicited by macroporous adsorptive resins column chromatography. Then the antiviral active component LC-4 was separated from the production by eluting. The cytotoxicities and antiviral effect of LC-4 were tested by the Neutral Red assay and the cytopathic effect (CPE) inhibition assay. Ribavirin was used as the positive drug in the study. The antiviral effect of prevention and treatment of maximum dose of non-cytotoxicity of LC-4 was tested in Hela cell line. RESULTS:LC-4 showed that the concentration were 25.4 microg/ml with the medium cytotoxicity and were 2.11 microg/ml with the medium effective concentration (EC50). The corresponding treatment index of LC-4 was 12.04. It also exhibited obviously inhibition effect on RSV replications when LC-4 was added at 2 h, 4 h, 6 h and 8 h after infection (P < 0.05). The CPE was significant difference in comparison with control group, when the concentration of LC-4 between 31.25 microg/ml and 3.91 microg/ml was added at 2 h before infection (P < 0.05). CONCLUSION:LC-4 could significantly prevent and inhibit RSV replications in vitro.