Table 1.
The inhibitory effect on cell-free and cell-based cleavage activity of the SARS-CoV 3CLpro
| Compound | Structure | IC50a of cell-free cleavage (μg/ml) | IC50a of cell-based cleavage (μg/ml) | CC50b of cell death (μg/ml) |
|---|---|---|---|---|
| Isatis indigotica root | 53.8 ± 4.2 | 191.6 ± 8.2 | >5000 | |
| Indigo |  |
37.3 ± 8.1 (300 μM) | 190 ± 2.6 (752 μM) | 917 ± 18 (7375 μM) |
| Indirubin |  |
81.3 ± 5.2 (293 μM) | NSc | |
| Indican |  |
33.1 ± 1.2 (112 μM) | NSc | |
| Sinigrin |  |
50.3 ± 1.5 (121 μM) | 90.1 ± 4.2 (217 μM) | >5000 (>10,000 μM) |
| Beta-sitosterol |  |
47.8 ± 8.6 (115 μM) | 502.1 ± 2.9 (1210 μM) | 613 ± 9 (1475 μM) |
| Aloeemodin |  |
35.7 ± 1.5 (132 μM) | 99.1 ± 2.1 (366 μM) | 3135 ± 9 (11,592 μM) |
| Hesperetin |  |
18.1 ± 0.6 (60 μM) | 2.5 ± 0.8 (8.3 μM) | 820 ± 15 (2718 μM) |
| Daidzein |  |
26.8 ± 1.2 (105 μM) | NSc |
a
IC50 (50% inhibitory concentration) was the concentration requiring for 50% inhibition on the cis-cleavage activity of 3CLpro.
b
CC50 (50% cytotoxic concentration) was the concentration giving half the OD570–630 of mock cells in MTT assay. IC50 and CC50 were determined using a computer program based on Fisher's statistical model.
c
Not significant.