Table 5.
Intracellular CE inhibition and Reduction of Sensitization of Cells to CPT-11 by Tanshinones and S. miltiorrhiza root (Danshen) extracts.
| Expt numbera | Sample | Intracellular CE inhibitionb (% ± SD) | CPT-11 GI50 (μM) | Fold change in GI50 (as compared to DMSO control for respective experiment) |
|---|---|---|---|---|
| 1 | None (DMSO) | - | 1.1 | - |
| Benzil | 83.8 ± 4.7 | 6.0 | 5.4 | |
| Miltirone (23) | 83.0 ± 3.3 | 8.5 | 7.7 | |
| 2 | None (DMSO) | - | 0.9 | - |
| Tanshinone I (21) | 68.7 ± 1.1 | 3.3 | 3.9 | |
| Dihydrotanshinone (22) | 80.8 ± 2.6 | 8.9 | 9.9 | |
| 3 | None (DMSO) | - | 0.44 | - |
| Tanshinone IIA (7) | 80.8 ± 2.7 | 2.2 | 5 | |
| Cryptotanshinone (24) | 81.0 ± 7.7 | 2.0 | 4.5 | |
| 4 | None (DMSO) | - | 1.3 | - |
| Danshen acetone extract (2.5μg/ml) | 88.1 ± 0.7 | 5.1 | 3.9 | |
| 5 | None (DMSO) | - | 2.0 | - |
| Fraction 16 (2.5μg/ml) | 89.4 ± 4.7 | 7.4 | 3.7 | |
| Tanshinone sulfonate (25) | 14.9 ± 6.7 | ND | - |
a
Five independent experiments were conducted for growth inhibition studies due to the large number of data points generated by the cell-based assays. The differences in the GI50 values observed are dependent upon the levels of expression of hiCE. Since this varies, each independent experiment has its own DMSO control, and fold changes are calculated from this value.
b
Data represent percentage reduction in 4-MUA metabolism 30s after addition of substrate. Results represent the data obtained from 3 individual experiments