Eupatorium purpureum. Queen of the Meadow.
Nat. Ord. — Asteraceae. Sex. Syst. — Syngenesia Aequalis.
Description. — This plant, likewise known by the names of Gravel root, Joe-pye, Trumpet-weed, is herbaceous, with a perennial, horizontal, woody caudex, with many long, dark brown fibers, which send up one or more solid, glabrous, green, sometimes purplish stems, five or six feet in hight, with a purple band at the joints, about an inch broad. The leaves are from three to six in a whorl about six inches apart, oblong-ovate, or lanceolate, pointed, rugosely or feather- veined, coarsely serrate, slightly scabrous, with a soft pubescence beneath along the midvein and veinlets, thin, soft, on petioles an inch long, and from eight to twelve inches long by three or four inches wide. The flowers are all tubular, purple, varying to whitish, and consist of numerous florets contained in an eight-leaved calyx. Heads in lax, very dense and compound corymbs, cylindrical, and from five to ten-flowered.
History. — Queen of the Meadow grows in swamps and low grounds from Canada to Virginia, and flowers in August and September. The root is the officinal part ; as found in the shops it consists of a blackish woody caudex, from which proceed numerous long fibers, from one to three lines in diameter ; externally they are covered with a dark-brown, longitudinally-furrowed cortex, beneath which the internal portion is white, or whitish-yellow, according to its age, the last color being the oldest. It has a smell somewhat resembling old hay, and a slightly bitter, aromatic, and faintly astringent, but not unpleasant taste, and yields its properties to water by decoction, or spirits. It has not been analyzed; a principle has been obtained from it, by Mr. J. B. Robinson of Cincinnati, to which he has given the name of Eupatorine. It is obtained by making a saturated tincture of the root, and adding to it an equal bulk of water slightly acidulated with muriatic acid; on distilling off the alcohol the resin is precipitated. It is a dark-brown resin, forming a yellowish-brown powder, with a peculiar, slightly-aromatic, not unpleasant odor, and a peculiar, slightly-bitterish taste. It is easily pulverized, but in a short time the powder forms a solid mass, of a dark-brown color, or if much exposed to the atmosphere, black, resembling asphaltum. Water alone, or acidulated with muriatic or sulphuric acids, does not dissolve it; but ammonia or liquor potassa added to water, dissolves it, the last forming a solution of a deep-red color, which on the addition of a few drops of muriatic acid, gives a clear, transparent liquor, with a light-yellow spongy substance floating on the surface, and which is, probably, the resin purified. It is partly soluble in alcohol, but becomes completely so on the addition of muriatic acid, to which, if water be added, a grayish milky opake liquid is formed, which on standing, or by evaporation of the alcohol, gives a light-brown precipitate. Ether dissolves it, and if ammonia be added, a separation ensues, the ether floating above with a yellow tinge, while the ammonia sinks, forming a clear dark-red solution ; if liquor potassa be added to the ethereal solution, it causes a light yellowish-red liquor above, and a dark one below. Chloroform partially dissolves it, and wholly so on the addition of ammonia, which separates the solution into a yellow fluid below, and a dark-brown liquid above. It is insoluble in oil of turpentine. The therapeutical properties of this resin are not yet understood ; it remains to be determined whether or no it possesses the virtues of the root.
Properties and Uses. — A valuable diuretic, stimulant, somewhat astringent, and tonic. Used with excellent effect in dropsical affections, strangury, gravel, and all chronic urinary disorders, hematuria, gout and rheumatism. Dose of the decoction of queen of meadow, from two to four fluidounces, three or four times a day.
Since writing the above, Mr. William S. Merrell has prepared an oleoresin from this plant, to which he has given the name of Eupurpurin; it may be obtained by adding the alcoholic tincture of the root, to twice its volume of water, and distilling off the alcohol, similar to the process for obtaining podophyllin, iridin, etc. It is of a thick, pilular consistence and a dark greenish-brown color, having a faint peculiar smell, and a slightly nauseous taste. It is soluble in alcohol or ether, and more speedily when these are hot ; slowly soluble in oil of turpentine, from which ether precipitates the resin, holding the oily portion in solution, and on the addition of alcohol the resin is redissolved. It is almost completely soluble in dilute alkalis, but completely so, on the addition of a small quantity of ether. Eupurpurin, in doses of three grains, repeated every three or four hours, is a most powerful diuretic, occasioning in some instances a most enormous flow of urine. It may be given in pill form, either alone, or combined with an equal quantity of castile soap. An excellent pill for many renal affections may be made, composed of eupurpurin three grains, geraniin two grains, and extract of nux vomica one-tenth of a grain. Divide into two pills. One of these pills may be given every four hours daily.
Off. Prep. — Decoctum Eupatorii Purpurei; Infusum Epigeae Compositum.