161. Podophyllum.—Podophyllum. Mayapple. Mandrake.
BOTANICAL CHARACTERISTICS.—Leaf 7-9-lobed; peltate. Flowering stem bearing two one-sided leaves with the stalk thickest near their inner edge. Flower large, white, nodding. Fruit ovoid, slightly acid, edible.
DESCRIPTION OF DRUG.—Rhizome 300 mm. (12 in.) or more long and 5 mm. (⅕ in.) thick, jointed, consisting of nodes and internodes, the length of the internodes being about 50 mm. (2 in.). The rhizome is very much thickened at the nodes, where it is sometimes branched laterally, each node having a circular scar on the upper side and about six to ten small brittle rootlets below or scars from broken rootlets; externally smooth, slightly wrinkled longitudinally, of an orange-brown color; fracture short, white and starchy, showing a rather thick bark, and from sixteen to thirty vascular bundles encircling a broad pith; the parenchyma contains chiefly starch. Odor faint and characteristic; taste sweetish, slightly acrid, and quite bitter.
Preparation of Podophyllin.—Composed of several resinous principles separable by solvents. Ether dissolves out a resin of bright yellow color, leaving a brown, odorless resin of little more prompt activity. A concentrated tincture is precipitated by water containing HCl. The precipitate is collected and dried.
Podophyllin is not found to any extent in the fresh drug, according to Lobman. It is developed to the fullest extent only by storage.
CONSTITUENTS.—Resins associated with other common vegetable principles; podophyllin (Resina podophylli, U.S.P.) 4 to 6 per cent., together with amorphous and crystalline principles. Later investigations have given prominence to the following: Podophyllotoxin, C15H14O6 (white crystals), converted by hydration into podophyllic acid, C15H16O7; picropodophyllin, isomeric with podophyllotoxin (inert); quercetin, yellow needles; podophylloresin (purgative). Some authorities state that the purgative principle is closely related to emodin. (See Rhamnus purshiana.)
ACTION AND USES.—Classed usually with the drastic cathartics. Dose: 10 to 20 gr. (0.6 to 1.3 Gm.). Podophyllin is an irritant to the mucous membrane; in small doses an active cathartic, having reputed cholagogue properties, hence the name "vegetable calomel." Dose: as a laxative 1/10 gr. (0.006 Gm.), as a purgative ¼ gr. (0.016 Gm.).
There is a remarkable difference shown in the medicinal activity of podophyllin, whether precipitated by water alone, whether by acidulated water, or by solution of alum. The one precipitated by water is said to be fifteen to twenty times as active as the one precipitated by acidulated water, and the one precipitated by alum much weaker than either.
- OFFICIAL PREPARATIONS.
- Fluidextractum Podophylli. Dose: 5 to 15 drops (0.3 to 1 mil).
- Resina Podophylli. Dose: ⅛ to ½ gr. (0.0081 to 0.0324 Gm.).