This section is from the book "Materia Medica And Therapeutics - Vegetable Kingdom", by Charles D. F. Phillips. Also available from Amazon: Materia Medica And Therapeutics: Vegetable Kingdom.
Active Ingredients. - The bark of the R. frangula contains a substance named "frangulin" by Casselman, who first obtained it pure. Its composition is said to be C6H6O3. It has been obtained in the form of citron yellow, satiny, tasteless, odorless crystals. It is insoluble in water, but soluble in 160 parts of hot alcohol.
Physiological Action. - It is a hydragogue cathartic and vermifuge (sometimes emetic), somewhat similar to, but milder in its action than R. catharticus.
Therapeutic Action. - The preparations of this bark seem latterly to be gaining in favor as mild cathartics, well adapted to some cases of habitual constipation. Its vermifuge properties should not be overlooked.
Preparations And Dose. - None officinal. The purgative dose of the powdered bark in decoction or otherwise is about 20 grains. Squibb prepares a fluid extract.)