Dictionary.net

A glycoside obtained from Digitalis purpurea; the aglycone is digitogenin which is bound to five sugars. Digitonin solubilizes lipids, especially in membranes and is used as a tool in cellular biochemistry, and reagent for precipitating cholesterol. It has no cardiac effects.

A saponin, C7H46O14+5H2O, occurring in digitalis and constituting a large part of German digitalin. Also called crystallized digitalin or digitin. It is soluble in water and in dilute alcohol and is said to have the property of rendering digitoxin capable of suspension in the infusion of digitalis. It is a circulatory depressant, when injected into the blood, but is not absorbed from the alimentary tract.