This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
Frangula. - Synonym. - Buckthorn. The bark of Rhamnus Frangula Linne (nat. ord. Rhamneae), collected at least one year before being used.
Europe and Northern Asia.
Quilled, about 1 mm. thick; outer surface grayish-brown, or blackish-brown, with numerous small, whitish, transversely elongated lenti-cels; inner surface smooth, pale, brownish-yellow; fracture in the outer layer short, of a purplish tint; in the inner layer fibrous and pale yellow; when masticated, coloring the saliva yellow; nearly inodorous; taste sweetish and bitter.
Fresh bark contains a glucoside, Frangulin, C20H20O10. This in the old bark has become converted into Emodin, C15H10O5 (also found in Rhubarb), to which the value of the bark is due. Two products are obtained from Frangulin by hydrolysis, Emodin and Rhamnose, C6H12O6.
Dose, 1/2 to 1 dr.; 2. to 4. gm.