| Compound | % Inhibitiona | % Enhancementb |
| Ursolic acid | 29.0 | - |
| Carnosol | 60.2 | - |
| Oleanolic acid | 31.0 | - |
| Salvigenin | 40.2 | 89.9 |
| Rosmanol | 26.7 | 99.7 |
| Cirsimaritin | 23.0 | 89.9 |
| Hispidulin | 81.7 | 52.2 |