Table 2.
Antiviral activity in influenza virus-infected MDCK cells.a
| Compound | Antiviral activity (μM) against A/HK/7/87 (wt M2) | Cytotoxicity (μM) | |
|---|---|---|---|
| EC50 (PRA)b | EC99 (Virus yield)c | CC50d | |
| 2 | 0.14 | ≥1.7 | 18 |
| 3 | ND | ≥50 | >100 |
| 7 | >50 | >2 | 10 |
| 8 | 1.0 | 3.5 | >100 |
| 11 | >100 | 76 | >100 |
| 13 | >10 | >10 | 25 |
| 15 | 10 | >50 | >50 |
| 16 | >5 | >10 | 25 |
| 17 | >10 | >2 | 15 |
| 18 | >10 | >2 | 6.2 |
| 19 | >5 | >2 | 19 |
| 20 | >10 | >2 | 3.8 |
|
| |||
| Amantadine | 0.14 | 0.51 | >500 |
| Rimantadine | 0.016 | 1.1 | >500 |
MDCK: Madin-Darby canine kidney cells; virus strain: A/HK/7/87 (A/H3N2 carrying wt M2). None of the compounds displayed activity against the A/PR/8/34 strain bearing the S31N mutant M2 channel (data not shown).
EC50 in the virus plaque reduction assay (PRA): concentration at which the plaque number is reduced by 50% compared to untreated virus control.
EC99: compound concentration giving 2-log10 reduction in virus yield, as determined by quantifying the virus in the supernatant at 24 h post infection, using an RT-qPCR based method.63
CC50: 50% cytotoxic concentration, as determined by the MTS cell viability test in uninfected cells exposed to the compounds during 72 h. Values shown are the mean of 2–3 determinations. ND, not determined.