one type of mutants resistant to these compounds ( designated as group a ) are highly resistant ( between 50 and 2000-fold ) to various cardiac glycosides and their genins such as ouabain , oleandrin , digitoxin , digitoxigenin , strophanthidin , convallatoxin , gitoxin , gitoxigenin , gitaloxin , bufalin , and digoxigenin , but exhibit no cross-resistance to sc4453 , a digoxin analog which contains a pyridazine ring in place of the lactone ring in the c-17 position .
C0012258
digitoxin
C0012257
digitoxigenin