Synonym: Digitalis leaf, Foxglove leaves
Biological source: Digitalis (purple foxglove leaves) consist of the dried leaves of Digitalis purpurea. It is dried at a temperate below 60 immediately after collecting the
leaves. It should not contain more than 5 percent of moisture.
Family: Scrophulariaceae
Geographical Source:
Digitalis is native of Western Europe, British Island and USSR countries. Crop is being cultivated in France, Germany, United Kingdom and Hungary.
Cultivation and Collection:
It requires well drained calcarious, sandy loam soil which should be rich in organic matter. Lime rich soil is essential for proper growth and glycosidic content of Digitalis lanata
but harmful for Digitalis purpurea which require acidic soil. The climatic conditions which are
required for luxuriant growth are well distributed rainfall (30-40 cm per annum), good sunshine and temperature range between 20-30°C. For cultivation of Digitalis the seeds can be sown directly or first nursery rising and then transplanted in the field.
Macroscopic Characters:
It is erect branched biennials attaining a height of 60-90 cm. Leaves are simple alternate
opposite. Digitalis is an insect pollinated plant, bees being the main pollinator. The colour of leaves is dark greyish green having slight odour or odorless, bitter taste. The leaves are ovate lanceolate to broadly ovate having size is about 10-40 cm in length and 4-20 cm in width.
Chemical Constituent:
Digitalis contains 0.2-0.45 percent mixture of both primary and secondary cardiac glycoside (cardenolide). Purpurea glycoside A & B and glucogitaloxin are primay glycoside possessing at C-3 of the aglycone, a linear chain of 3 digitoxose moieties terminated by
glucose. Digitalis also contains many other glycosides viz odoroside H, gitaloxin, verodoxin and glucoverodoxin.
Chemical Test:
Legal test: Extract is dissolved in pyridine and sodium nitro prusside solution is added to it and made alkaline. Pink or red colour is produced.
Baljet test: To a section of digitalis leaf, sodium picrate solution is added. It shows yellow to orange colour.
Uses:
Most frequent use of digitalis is the treatment of congestive heart failure. Another major use of digitalis is slowing ventricular rate in atrial fibrillation, artrial flutter, supraventricular tachycardia and premature extra systole. Digitalis has a cumulative effect in body and is
slowly eliminated. Hence dosage is important aspects. Dose- initial dose 1-2 gm in 24-48 hrs. Maintenance dose - 100 mg daily.