Pyrethrum. U. S. (Br.) Pyrethrum.

Pyreth. [Pellitory Root]

Preparation: Tincture of Pyrethrum

"The dried root of Anacyclus Pyrethrum (Linné) Dc Candolle (Fam. Compositae). Preserve Pyrethrum in tightly-closed containers, adding a few drops of chloroform or carbon tetrachloride, from time to time, to prevent attack by insects." U. S. "Pyrethrum Root is the dried root of Anacyclus Pyrethrum DC." Br.

Pyrethri Radix, Br.; Pyrethrum Root; Radix Pyrethri Romani; Spanish Chamomile, Longwort, Pellitory of Spain; Pyrethre officinal, Fr. Cod.; P. vrai, Salivaire, Fr.; Bertramwurzel, Römische Bertramwurzel, G.; Pelitre (Raiz de), Sp.

Anacyclus Pyrethrum is perennial, and sends up numerous stems, usually trailing at the base, erect in the upper portion, eight or ten inches high, and terminated by one large flower. The leaves are doubly pinnate, with narrow, nearly linear segments of a pale-green color. The florets of the disk are yellow; the rays white on their surface, and reddish or purple beneath and at their edges.

The plant is a native of Northern Africa, the Levant, and the Mediterranean coast of Europe, being also cultivated. The root is the part used under the name of pellitory, or pellitory of Spain.

The German Pharmacopoeia formerly recognized the root of Anacyclus officinalis Hayne (A. Pyrethrum Schrader), a plant cultivated in Magdeburg. The roots are smaller and thinner, attaining a length of 25 cm. and a thickness of 5 cm. They are externally grayish-brown; the bark is not radiating and does not contain many stone cells, such as are present in the official pyrethrum. The taste resembles that of the official drug but is even more pungent.

Properties.—Pyrethrum is officially described as "nearly cylindrical, slightly tapering, usually in pieces from 2.5 to 10 cm. in length and from 5 to 20 mm. in diameter; externally dark brown, deeply longitudinally furrowed and somewhat wrinkled, occasionally bearing short, tough, hair-like rootlets, crown more or less annulate, and occasionally tufted with coarse fibers or with long, soft-woolly, nearly straight, 1-celled hairs; fracture short; bark dark brown with 1 or 2 circular rows of resin ducts, closely adhering to the light yellow, radiate, porous wood, in the medullary rays of which occur 1 to 3 rows of resin ducts; odor distinct; taste sweetish, pungent, very acrid, tingling and producing a strong sialagogue effect. The powder is light to dark brown; when examined under the microscope it exhibits numerous spherical or irregular masses of inulin, the nature of which is especially seen with polarized light, and lignified fragments of the woody tissues and stone cells associated with cork; inulin in spherical granules or irregular masses, from 0.01 to 0.1 mm. in diameter, which is not affected by the addition of iodine T.S.; trachea; with simple pores and reticulate or scalariform thickenings, usually associated with wood parenchyma and with few or no wood fibers; stone cells in groups, the cells more or less tabular in outline and with thick, yellowish porous walls; cork in yellowish-brown or dark brown fragments. Pyrethrum yields not more than 5 per cent. of ash." U. S.

"Usually from five to ten centimetres long, and from ten to fifteen millimetres thick; un-branched, nearly cylindrical, or frequently tapering towards both extremities; the crown often bearing a tuft of nearly colorless hairs. Outer surface brown and longitudinally wrinkled. Fracture short. In transverse section, numerous, narrow, yellowish wood-bundles alternating with wider, brownish-grey medullary rays; in the cortex and medullary rays scattered, yellowish-brown oleo-resin ducts; in the parenchymatous tissue inulin, but no starch. Characteristic odor; taste pungent, salivant." Br.

Its analysis by Koene gives, in 100 parts, 0.59 of a brown, very acrid substance, of a resinous appearance, and insoluble in potassium hydroxide (this is stated to contain pelletonin), 1.06 of a dark brown, very acrid, fixed oil, soluble in potassium hydroxide; 0.35 of a yellow acrid oil, also soluble in potassium hydroxide; traces of tannin; 940 parts of gum; inulin; 7.60 parts of potassium sulphate and carbonate, potassium chloride, calcium phosphate and carbonate, alumina, silica, etc., and 19.80 of lignin, besides loss. (See A. J. P., viii, 175.) Buchheim (A. E. P. P., v, 458) claims to have discovered as the active principle an alkaloid, pyrethrine, which, treated with alcoholic potassium hydroxide, splits up like piperine, and yields pyrethric acid. Schneegans (Proc. A. Ph. A., 1897, 736) has obtained this pyrethrine in long branched needles united in tufts, melting at 46° C. (114.8° F.), with an extremely burning taste. It is soluble in absolute alcohol, acetone, ether, strong acetic acid, chloroform, and carbon disulphide, yields a yellow solution, which soon changes to red.

A false pellitory root has been identified by E. M. Holmes as the product of Corrigiola telephiifolia. It is readily distinguished from the true root by its being softer and more flexible, by its having a distinctly sweetish taste, and especially by the transverse section of the root, which is of a yellowish-white color, with from three to five pale opaque concentric rings, each alternating with a narrower translucent horny ring.

Uses.—Pellitory is a powerful irritant, used (the rest is missing. -Henriette)

The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.