Organic synthesis and anti-influenza A virus activity of cyclobakuchiols A, B, C, and D
Fig 4
Image analysis of inhibitory effect of cyclobakuchiols A–D on influenza A viral infection.
The corresponding concentrations of cyclobakuchiols A (2), B (3), C (4), and D (5) (3.1–12.5 μM; n = 9 each), (+)-(S)-bakuchiol (1) (3.1–12.5 μM; n = 9 each), or DMSO (0.031–0.125%; n = 9 each) were mixed with A/PR/8/34 (A and B) or A/WSN/33 (C and D) viruses and added to MDCK cells for 24 h. The infected MDCK cells were visualized by immunofluorescence staining of influenza A viral NP and then photographed under a microscope (A and C). The percentages of influenza A viral NP-positive cells per DAPI-positive cells were calculated based on the counts of influenza A viral NP-positive and DAPI-positive cells (B and D). The white scale bar in each image represents 100 μm. Data are expressed as the mean ± SEM of three independent experiments. *p < 0.05, **p < 0.01, ***p < 0.001 relative to DMSO-treatment. ††p < 0.01 relative to cyclobakuchiol D-treatment. The results were reproducible in this experiment.