Frangula (U. S. P.)—Frangula.
"The bark of Rhamnus Frangula," Linné, "collected at least one year before being used"—(U. S. P.) (Frangula Alnus, Miller Frangula vulgaris, Reichenbach).
COMMON NAMES: Buckthorn (U. S. P., 1880), Alder buckthorn.
ILLUSTRATION: Bentley and Trimen, Med. Plants, 65.
Botanical Source.—The alder buckthorn is a smooth shrub growing to the height of from 10 to 15 feet. Its leaves are oval, obovate, or elliptic, broad, obtuse, and entire, or scarcely sinuate. The under surface is faintly downy. The flowers, which are greenish and hermaphrodite, are borne in the axils to the number of 2, 3, and 5. All the floral parts are 5 in number. The fruit is a nearly black (first red) berry, about, the size of the common pea, and contains rounded-angular (2 or 3) seeds.
History and Description.—This shrub grows in wet situations throughout Europe, Siberian Asia, and the North African coast. It is improperly called Black alder in some parts of Europe. The bark is collected from the larger branches and the young tree-trunks in the spring of the year. It should not be used until at least a year old. The U. S. P. describes the drug as follows: "Quilled, about 1 Mm. (1/25 inch) thick; outer surface grayish-brown, or blackish-brown, with numerous small, whitish, transversely-elongated lenticles; 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"—(U. S. P.). It yields with cold water a yellow, and with hot water, a brown colored infusion.
Chemical Composition.—This bark contains tannin, purgative extractive matter, an amorphous, non-purgative bitter, and an odorous, volatile principle not yet isolated. The chief constituent, however, is the glucosid frangulin (Casselmann), or rhamnoxathin (C21H20O9, Schwabe, and confirmed by T. E. Thorpe and A. K. Miller, 1892). Carbon disulphide extracts it from the bark, and the principle may be recrystallized from ether or alcohol (see Proc. Amer. Pharm. Assoc., 1892). This body forms silky-lustrous, lemon-yellow crystals. Yellow needles are obtained by sublimation. Frangulin dyes cotton, wool, and silk. It is inodorous and tasteless, soluble in alkaline solutions (with a vivid purple color), but little soluble in ether or cold alcohol, and not at all soluble in water. Upon hydrolysis with dilute acids it yields emodin (C15H10O5. (or tri-oxy-methyl-anthra quinone) and rhamnose (frangula sugar) (C6H12O5. (Proc. Amer. Pharm. Assoc., 1892, p. 719). Impure frangulin was named avornin by Kubly, in 1866. Emodin from this source was identified as such by Liebermann and Waldstein, in 1876, the name frangulic acid (frangulinic acid) having been previously affixed to it by Faust, in 1869. Both principles (frangulin and emodin) are only to be found in aged bark (Amer. Jour. Pharm., 1888, p. 515).
Action, Medical Uses, and Dosage.—Nausea, colicky pain, and violent emeto-catharsis are the effects produced by fresh frangula bark. When dried, however, it loses some of its acridity, and then acts as a purgative only. Both the alvine and renal discharges are colored dark-yellow by it. Narcotic symptoms have been produced by eating the berries and seeds, the toxic effects having been probably produced by the prussic acid contained in the seeds. The decoction has been administered in dropsies, and the same preparation as well as an ointment of the recent bark, has been used for the cure of itch. Its chief value, however, is as a laxative and cathartic, being quite popular for these effects with the Germans. It resembles senna and rhubarb in action, according to some, being harsher, but is regarded by Squibb as milder than either. It is a remedy for chronic constipation, from 1 to 3 doses of 20 minims of the fluid extract being administered in water in the course of a day. If desirable to evacuate the bowels at once, a fluid drachm may be given at bedtime. An elixir (4 parts of fluid extract to 12 parts of elixir of orange) may be given in from 1 to 2 fluid drachm doses; of the decoction (½ ounce of bark to ½ pint of water) the dose is a tablespoonful.