Gitostin, a new cardiotonic glycoside isolated from the seeds of Digitalis purpurea, was hydrolyzed with digestive enzyme from the intestine of a snail (Euhadra quaesita DESHAYES) and strospeside was obtained, confirming the structure of gitostin as gitoxigenin-glucosido-glucosido-digitaloside. Partial decomposition of gitostin with the same enzyme afforded digitalinum verum, indicating that this enzyme effected stepwise hydrolysis, liberating one mole each of glucose. From the fact that only digitalinum verum is obtained from gitostin, the extra glucose was found to be bonded to the glucose in digitalinum verum, and by the comparison of molecular rotation of gitostin and digitalinum verum, the bonding of this glucosylglucoside was confirmed to be in β-position to the terminal glucose.
