Bufanolides

Bufadienolide is a chemical compound with steroid structure. Its derivatives are collectively known as bufadienolides, including many in the form of bufadienolide glycosides (bufadienolides that contain structural groups derived from sugars). These are a type of cardiac glycoside, the other being the cardenolide glycosides. Both bufadienolides and their glycosides are toxic; specifically, they can cause an atrioventricular block, bradycardia (slow heartbeat), ventricular tachycardia (a type of rapid heartbeat), and possibly lethal cardiac arrest.

Bufotalin is a cardiotoxic bufanolide steroid, cardiac glycoside analogue, secreted by a number of toad species. Bufotalin can be extracted from the skin parotoid glands of several types of toad.

Scilliroside is a toxic compound derived from the plant Drimia maritima (syn. Urginea maritima), which is sometimes used as a rodenticide.

Marinobufagenin (marinobufagin, MBG) is a cardiotonic bufadienolide steroid. It is secreted by the toad species such as Bufo marinus. It also can be found in the plasma and urine of human subjects with myocardial infarction, kidney failure, heart failure, and preeclampsia. MBG is a vasoconstrictor and a sodium–potassium adenosine triphosphatase (Na/K-ATPase) inhibitor with a high affinity for the alpha-1 isoform of the enzyme, the main isoform in the vascular wall and the kidney.

Proscillaridin is a cardiac glycoside, a type of compound with strong and usually toxic effects on heart muscle, with occasional medical applications - although Proscillaridin has no known medical applications. It is of the bufanolide type and can be obtained from plants of the genus Scilla and in Drimia maritima (Scilla maritima).

Bufagin is a toxic steroid C24H34O5 obtained from toad's milk, the poisonous secretion of a skin gland on the back of the neck of a large toad (Rhinella marina, synonym Bufo marinus, the cane toad). The toad produces this secretion when it is injured, scared or provoked. Bufagin resembles chemical substances from digitalis in physiological activity and chemical structure.

Daigremontianin is a bufadienolide. Bufadienolides are steroids and cardiac glycoside aglycones (meaning that they bind with carbohydrates to form cardiac glycosides) that are similar to cardenolides, differing only in the structure of the C-17 substituent on the D ring. This chemical has been found to be toxic in experiments on mice. It is one of five bufadienolides that have been isolated from Kalanchoe daigremontiana.