To observe the inhibitive effect of
Baicalin against
influenza A H1N1 virus
infection in epithelial cell line A549, the cell proliferation and cytotoxicity were assayed by MTT, the cell cycle and the apoptosis were analyzed by flowcytometer using PI staining, the morphology of cellular nucleolus was observed by
Hoechst 33258 staining and the effects of activation on
caspase 3 and
caspase 8/9 were also detected by immunofluorescent staining with a fluorescence microscope. The results showed that
Baicalin exerted an inhibitive effect on CPE after
influenza A H1N1 virus
infection. The FACS with PI staining showed that the cell cycle of the infected cell was arrested at S phase, the
Baicalin-treated group decreased S phase cell ratio and subG0 phase peak in comparison with the control (P < 0.05) and significantly promoted cell proliferation (# P < 0.05). Hoechst33258 staining suggested that
Baicalin protected the cellular nucleolus against the influenza virus-induced apoptosis. Observation under the immunofluorescent microscope suggested that the activities of
caspase-8 and
caspase-3 were enhanced at 36 h post the influenza virus
infection, but 100 microg/mL
Baicalin suppressing the activation of
caspase-8 and
caspase-3 rather than that of
caspase-9. In summary, this research confirmed that
Baicalin inhibited the
influenza A H1N1 virus strain
infection in vitro, the
drug obviously protected cells from apoptosis damages through regulating cell cycle and suppressed the activation of
caspase-8 and
caspase-3. The down-regulation was significant and showed a dose-dependent relationship.