- bufanolide
- The fundamental steroid lactone of several vegetable ( e.g., squill) and animal ( e.g., toad) venoms or toxins; also found in the form of glycosides in plants ( e.g., digitalis). The steroid is essentially a 5β-androstane, with a 14β H. The lactone at C-17 is structurally related to the —CH(CH3)CH2CH2CH3 radical attached to C-17 in the cholanes, and is in the same configuration as that of cholesterol ( i.e., 20R); in some species, b. is formed from cholesterol. Various b. derivatives having unsaturation in the lactone ring (20, 22) or elsewhere (4) are known as bufenolides (one double bond), bufadienolides (two double bonds), bufatrienolides (three double bonds), etc; they have varying numbers of hydroxyl groups at positions 3, 5, 14, and 16, and these may be further substituted. For structure, see steroids.
Medical dictionary. 2011.