Table 2.
Protease inhibition, anti-SARS, and cytotoxicity properties of the dipeptide inhibitors 18a–e
| Compound | IC50 (μM)a | Ki (μM) | EC50 (μM) | CC50 (μM)b | S.I.c |
|---|---|---|---|---|---|
| 1a | >100 | NDd | —e | ND | |
| 3c | 13 | NDd | —e | ND | |
| 18a | 10 | 6.44 ± 0.8 | 18.86 | >200 | >10 |
| 18b | 5 | 2.48 ± 0.89 | 9.45 | >200 | >20 |
| 18c | 1 | 0.52 ± 0.024 | 0.18 | >200 | >1000 |
| 18d | 10 | 9.049 ± 2.35 | 0.11 | >200 | >1000 |
| 18e | 7 | 3.046 ± 0.61 | 0.16 | >200 | >1000 |
a
The highest concentration of samples is 10 μM in the assay against the SARS-CoV 3CL protease.
b
The highest concentration of sample is 200 μM in the assay of cytotoxicity on Vero E6 cells.
c
Selectivity index, the ratio of CC50 to EC50.
d
Not determined.
e
No protective effect against infection of Vero E6 cells at the concentration of 10 μM.