Table 4. Effect of pure optical isomers of silybin, 2,3-dehydrosilybin, 7-O-methylsilybin, and 7-O-galloylsilybin on HTB9, HCT116, and PC3 cancer cell growth.
| Treatments | Total cell no. x105 (% growth inhibition) | |||
| HTB9 Cells | 24 hrs | 48 h | ||
| 30 µM | 60 µM | 30 µM | 60 µM | |
| DMSO | 2.5±0.1 | 5.5±0.2 | ||
| Silybin A | 2.0±0.1# (20%) | 2.0±0.3$ (20%) | 4.7±0.8* (15%) | 3.9±0.3* (29%) |
| 2,3-dehydrosilybin A | 1.8±0.1* (28%) | 1.3±0.1* (48%) | 1.8±0.1* (67%) | 1.3±0.0* (76%) |
| 7-O-methylsilybin A | 1.5*±0.1* (40%) | 1.2±0.1* (52%) | 1.8±0.1* (67%) | 0.5±0.1* (91%) |
| 7-O-galloylsilybin A | 1.7±0.1* (32%) | 1.0±0.0* (60%) | 1.5±0.1* (73%) | 1.1±0.1* (80%) |
| Silybin B | 2.2±0.1 (12%) | 1.7±0.2* (32%) | 4.2±0.3* (24%) | 3.3±0.3* (40%) |
| 2,3-dehydrosilybin B | 1.3±0.1* (48%) | 1.3±0.1* (48%) | 1.5±0.1* (73%) | 1.4±0.1* (75%) |
| 7-O-methylsilybin B | 2.1±0.1 (16%) | 1.2±0.2* (52%) | 2.2±0.1* (60%) | 0.9±0.1* (84%) |
| 7-O-galloylsilybin B | 1.3±0.1* (48%) | 0.8±0.2* (68%) | 1.4±0.1* (75%) | 0.9±0.1* (84%) |
| HCT116 Cells | 24 hrs | 48 h | ||
| 30 µM | 60 µM | 30 µM | 60 µM | |
| DMSO | 3.6±0.2 | 8.6±0.4 | ||
| Silybin A | 3.4±0.3 (6%) | 2.9±0.3# (19%) | 8.7±0.4 (−1%) | 7.0±0.3* (19%) |
| 2,3-dehydrosilybin A | 1.9±.0.1* (47%) | 1.7±0.2* (53%) | 1.7±0.1* (80%) | 1.0±0.1* (88%) |
| 7-O-methylsilybin A | 2.0±0.3* (44%) | 1.2±0.2* (67%) | 1.1±0.1* (87%) | 0.8±0.2* (90%) |
| 7-O-galloylsilybin A | 1.8±0.2* (50%) | 1.0±0.1* (72%) | 1.0±0.0* (88%) | 0.6±0.1* (93%) |
| Silybin B | 3.2±0.1 (11%) | 3.3±0.1 (8.3%) | 7.2±0.2* (16%) | 6.1±0.6* (29%) |
| 2,3-dehydrosilybin B | 2.2±0.0* (39%) | 1.2±0.1* (67%) | 1.3±0.1* (85%) | 1.2±0.1* (86%) |
| 7-O-methylsilybin B | 2.6±0.3* (28%) | 1.3±0.1* (64%) | 2.0±0.1* (77%) | 1.0±0.1* (88%) |
| 7-O-galloylsilybin B | 1.5±0.1* (58%) | 1.1±0.1* (69%) | 0.8±0.2* (91%) | 1.0±0.0* (88%) |
| PC3 cells | 24 hrs | 48 h | ||
| 30 µM | 60 µM | 30 µM | 60 µM | |
| DMSO | 2.2±0.10 | 4.5±0.2 | ||
| Silybin A | 1.9±0.01 (14%) | 1.9±0.1 (14%) | 4.0±0.2 (11%) | 3.7±0.3* (17.8%) |
| 2,3-dehydrosilybin A | 0.7±0.0* (68%) | 0.1±0.1* (95%) | 1.2±0.0* (73%) | 1.3±0.1* (71%) |
| 7-O-methylsilybin A | 0.8±0.1* (64%) | 1.1±0.1* (50%) | 1.0±0.2* (78%) | 0.9±0.0* (80%) |
| 7-O-galloylsilybin A | 1.7±0.4$ (23%) | 0.7±0.1* (68%) | 0.8±0.1* (82%) | 1.1±0.1* (76%) |
| Silybin B | 1.7±0.1$ (23%) | 1.6±0.1* (27%) | 3.6±0.2* (20%) | 3.3±0.1* (27%) |
| 2,3-dehydrosilybin B | 1.1±0.1* (50%) | 1.1±0.1* (50%) | 1.1±0.1* (76%) | 1.0±0.1* (78%) |
| 7-O-methylsilybin B | 1.2±0.2* (45%) | 1.2±0.1* (45%) | 1.2±0.3* (73%) | 1.3±0.1* (71%) |
| 7-O-galloylsilybin B | 0.4±0.0* (82%) | 0.3±0.1* (86%) | 0.7±0.1* (84%) | 0.4±0.1* (91%) |
*
p≤0.001;
#
p≤0.01;
$
p≤0.05.