Definition: Cyclopentanophenanthrenes with a 6-membered lactone ring attached at the 17-position and SUGARS attached at the 3-position. They are found in BUFONIDAE and often possess cardiotonic properties.
marinobufagenin [ marinobufogenin ] an endogenous digitalis-like factor; a Na(+),K(+)-ATPase inhibitor and cardiotonic agent; structure given in first source