“…Alternatively, SAL, NIG and OBT may serve as lead compounds to develop derivatives more selective towards non-cancer cells. In this context, several derivatives of OBT [ 172 , 173 ] and SAL [ 120 , 121 , 174 , 175 , 176 , 177 , 178 , 179 ] have shown anticancer effects. For instance, derivatives with chemical modification of the allylic C20 hydroxyl of SAL, located at the C-ring, enhanced the activity over 5-fold against breast cancer cells compared to the native structure [ 121 ].…”