Objective: To study the inhibitive effects of an effective section of a prescription of traditional Chinese medicine (TCM-ES) on influenza virus A FM1 strain in vitro.
Methods: The experiments were performed by microcytopathic-inhibiting-assay, Neutral Red stain and inhibiting plaque-forming units (PFU) test on MDCK cell strain. By means of observing the cytopathic effects (CPE), measuring the absorbance [D(lambda)] and counting the PFU, according to Reed-Muench assay, the TCM-ES's effective dosage of 50 percentage (EC50) and treatment index (TI) to FM1 were calculated. The inhibiting dose of 50 percentage of PFU (IC50) was also figured up.
Results: By CPE assay, TCM-ES'S EC50, MTC and TI to 100TCID50 FM1 strain infection were (300 +/- 18.3) mg/L, (75 +/- 6.8) mg/L and (7.1 +/- 0.7), respectively; Whereas, ribavirin's EC50, MTC and TI was (52.3 +/- 10.1) mg/L, (25 +/- 4.1) mg/L and (20.8 +/- 5.1), respectively. By Neutral Red stain assay,TCM-ES's IC50 and TI was (285.0 +/- 19.2) mg/L and (7.2 +/- 0.6), respectively; whereas ribavirin's IC50 and TI was (45.3 +/- 4. 9) mg/L and (21.2 +/- 3.1), respectively. By reducing PFU assay, the IC50 of TCM-ES and ribavirin was 300 mg/L and 50 mg/L, respectively. All the results above were almost consistent with each other (P > 0.05).
Conclusions: TCM-ES assumes antiviral action on IFV-FM1 strain in a certain degree in vitro and can rebel intracellular virus. But it is worse than the positive control medicine of ribavirin and is worthy of further study.