ABSTRACT
Toxic Principle and Mechanism of Action A variety of cardiotoxic bufadienolides are present in all parts of the plant, but especially in the flowers.1,2 The cardiotoxins, including bryotoxins, bryophyllins, and bersalgenins, have similar action to the cardiac glycosides found in foxglove, oleander, Lily of the valley, and milkweeds. Their primary effect is to inhibit Na+/K+ adenosine triphosphatase, thereby decreasing the transportation of sodium and potassium across cell membranes which decreases cardiac function. The most toxic species is K. delagonensis and its hybrids.3 Although there is considerable variation in the toxicity of the Kalanchoe species, all species should be considered toxic until proven otherwise.
