Xanthoxylum is the dried bark of Xanthoxylum Americanum, Miller, or of Fagara (Xanthoxylum) Clava-Herculis, Linn. (N.O. Rutaceae), two American shrubs, the first (Northern Prickly Ash) growing in moist shady places throughout the Northern, Middle, and Western States, while the second (Southern Prickly Ash) occurs in the South, from Virginia to Texas. The drug is official in the U.S.P. Northern Prickly Ash bark occurs in curved or quilled brownish-grey fragments, about 1 millimetre thick, with whitish patches and minute black dots, faintly furrowed, and with some brown, glossy, straight, two-edged spines about 5 millimetres long; the inner surface whitish, smooth. The bark breaks with a short, non-fibrous fracture, green in the outer and yellowish in the inner layer; it is odourless, but has a bitterish, very pungent taste. Southern Prickly Ash bark occurs in large, light purplish-grey quills and sheets, 1 to 2 millimetres thick, with large silvery-grey patches and many large corky projections, frequently 2 centimetres high, which often bear stout brown spines; otherwise like the Northern Prickly Ash. Xanthoxylum must be distinguished from the bark of Aralia spinosa, Linn. (N.O. Araliaceae), which is nearly smooth externally and beset with slender prickles in transverse rows.
Constituents.—The active constituents of the two barks appear to be acrid and bitter resins, but a crystalline substance named xanthoxylin has been obtained from the bark of X. Americanum, and an alkaloid, probably berberine, from the bark of F. Clava-Herculis.
Action and Uses.—Xanthoxylum acts as a stimulant, and produces when swallowed a sense of warmth and comfort in the stomach, followed, after absorption, by some diuresis and diaphoresis. It resembles guaiacum resin and mezereon bark in its action, and is used in similar cases, being administered in the form of fluidextract. The name "xanthoxylin " is also applied to a resinoid extractive prepared by pouring a tincture or fluidextract of the drug into water. This resinoid is the substance commonly prescribed in doses of ½ to 2 decigrams (1 to 4 grains) as xanthoxylin.
Dose.—1 to 2 grammes (15 to 30 grains).
- Fluidextractum Xanthoxyli, U.S.P.—FLUIDEXTRACT OF XANTHOXYLUM. Syn.—Extractum Xanthoxyli Fluidum.
- Xanthoxylum, in No. 40 powder, is exhausted by macero-percolation with alcohol (71 per cent.), and the volume of the product adjusted so that 1 fluid part represents 1 part of drug. Average dose.—2 mils (30 minims).