ABSTRACT
The digitalis is used for drug preparations that contain cardiac glycosides, in particular digoxin. This works by increasing the intensity of the heart muscle contractions but diminishing the rate, and has been used in the treatment of heart conditions ever since its discovery in 1775. Digitalis has also been a remedy for dropsy, which was the old term for swelling of soft tissue in the legs and arms. Unknown to the physicians at the time, these swellings were often caused by poor blood circulation due to heart problems. Digitalis purpurea plants contain a mixture of several cardiac-active molecules related to digitalis in amounts and proportions which vary with locality and with season. Before modern synthetic methods, therefore, digitalis preparations varied considerably in potency and quality. Hydrolysis of the digitalis extract produces many related molecules, all of which contain an α,β-unsaturated lactone ring in addition to other structural similarities.
