Fig. 2

Influence of different treatment conditions of Patchouli alcohol on IAV infection. a MDCK cells were infected with H1N1 (Vir09, MOI =1.0) by four different treatment conditions. i) Pretreatment of virus: IAV was pretreated with 25 μg/ml of PA at 37 °C for 1 h before infection. ii) Pretreatment of cells: MDCK cells were pretreated with 25 μg/ml of PA at 37 °C for 1 h before infection. iii) Adsorption: MDCK cells were infected in media containing 25 μg/ml of PA and, after 1 h adsorption at 37 °C, were overlaid with compound-free media. iv) After adsorption: after removal of unabsorbed virus the infecting media containing 25 μg/ml of PA were added to cells. At 24 h p.i., the antiviral activity was determined by plaque assay. Values are means ± S.D. (n = 3). *P < 0.05, **P < 0.01 vs. virus control group. b PR8 (MOI = 1.0) infected MDCK cells were treated with or without 25 μg/ml of PA for the specified time period, and then the media were removed and cells were overlaid with compound-free media. Then at 24 h p.i., the cell supernatants were collected and the virus yields were determined by plaque assay. Values are means ± S.D. (n = 3). Significance: *p < 0.05 vs. virus control group. c Inactivated H1N1 (Vir09) virus and H1N1(PR8) was incubated with indicated concentrations of PA or Zanamivir (10 μg/ml), and the NA enzymatic activity was determined by a fluorescent assay. Values are means ± S.D. (n = 3). d The inhibition effects of PA and anti-HA antibody on influenza virus H1N1 (PR8) induced aggregation of chicken erythrocytes were evaluated by hemagglutination inhibition (HI) assay. e 293FT cells were transfected with pcDNA3.1 expression plasmids encoding PB2, PB1, PA, NP, and the vNS1-luc plasmid in the absence or presence of PA (3.125, 6.25, 12.5, 25 and 50 μg/ml) or Nucleozin (10 μM). The effect of vRNA transcription was then evaluated by measuring luciferase activity at 48 h post-transfection. Data are expressed as the mean ± SD of three samples in each of three independent experiments. Significance: **p < 0.01 vs. mock control group