Pyrethrum (U. S. P.)—Pyrethrum.
The root of Anacyclus Pyrethrum (Linné), De Candolle (Anthemis Pyrethrum, Willdenow; Matricaria Pyrethrum, Baillon).
COMMON NAMES: Pellitory, Pellitory root, Pellitory of Spain, Spanish chamomile.
ILLUSTRATION: Bentley and Trimen, Med. Plants, 151.
Botanical Source, History, and Description.—This is the Anthemis Pyrethrum of Willdenow, the name of which has been changed by De Candolle, and the plant placed in a new genus on account of a difference in the structure of its seeds. The stems are numerous, procumbent, somewhat branched, and pubescent. The radical leaves are spreading, petiolated, smoothish, and pinnately divided; the segments much-cleft into linear, subulate lobes; and the cauline leaves sessile. Branches 1-headed. Receptacle convex, with oblong-obovate, obtuse paleae; ray sterile, ligulate, and white; of the disk, fertile, with 5 callous teeth, and yellow (L.). Pellitory of Spain, or Spanish chamomile, inhabits Barbary, Arabia, Syria, etc. The root is the official part, and is officially described as "from 5 to 10 Cm. (2 to 4 inches) long, and 1 to 2 Cm. (1/4 to 3/5 inch) thick, somewhat fusiform, nearly simple, annulate above, wrinkled below; externally dark grayish-brown; internally brownish-white; fracture short; bark rather thick, containing 2 circles of resin cells, and surrounding the slender wood-bundles and medullary rays, the latter having about 4 circles of shining resin-cells; inodorous, pungent, and very acrid"—(U. S. P.). The root, when chewed, produces a peculiar sensation of pricking in the lips and tongue, and a glow of heat, with an increase of the salivary discharge. It maybe readily distinguished from False pellitory root, identified by Mr. E. M. Holmes (Amer. Jour. Pharm., 1892, p. 90), as derived from Corrigiola telephiifolia, a Morocco plant, chiefly by the appearance of its cross-section (see illustration, loc. cit.).
Chemical Composition.—In 1835, Koene found it to contain a brown acrid resin, insoluble in caustic potash; an acrid, brown fixed oil, soluble in caustic potash; a yellow, acrid oil, also soluble in this solvent; a trace of tannic acid, gum, inulin, various salts, and lignin. Alcohol or ether dissolves its active principle. This is claimed by Buchheim (1876) to be an alkaloid, pyrethrine, a body splitting into piperidine and an acid, resembling piperic acid, called pyrethric acid, when treated with alcoholic solution of caustic potash (see Piperinum). The pyrethrin of Thompson (Pharm. Jour. Trans., Vol. XVII, 1887, p. 567) is an ether-extract, composed of acrid fat and resin. This author found the cortical portion of the root to contain 5 per cent of pyrethrin. Volatile oil is likewise present. Dunstan and Garnett (Jahresb. der Pharm., 1895, p. 64) isolated from the resin crystallizable pellitorin, insoluble in water, diluted acids, and alkalies, soluble in alcohol. It resembles piperovatin (C16H21NO2), the non-basic, active principle isolated by the same authors from the resin obtained from the leaves ofPiper ovatum. Both are pyridine derivatives.
Action, Medical Uses, and Dosage.—It is an energetic local irritant and sialagogue, and acts as a rubefacient when applied externally. Its ethereal tincture relieves toothache. The root chewed has been found useful in some rheumatic and neuralgic affections of the head and face, and in palsy of the tongue. The decoction has been used as a gargle in relaxation of the uvula. Severe acronarcotic symptoms, with inflammation of the alimentary tract and bloody stools, were produced in a young child by less than a drachm of the tincture. The dose is from 30 to 60 grains as a masticatory. Oil of pellitory is made by evaporating the ethereal tincture; it is an excellent remedy for toothache.
Related Species and Drugs.—Anacyclus officinarum, Hayne, German pellitory. A cultivated plant of Germany. By some considered an annual form of Anacyclus Pyrethrum. Its action is the same as, but weaker than, the latter.
SWEET PELLITORY, ascertained by Dr. Dymock to be derived from Tanacetum umbelliferum, Boissier, is a Persian drug, imported into Bombay, of a sweetish taste and an odor resembling that of Chaulmoogra oil. It contains only a small amount of pyrethrin (see D. Hooper, Amer. Jour. Pharm., 1890, p. 504).
INSECT POWDERS.—These are yellowish or drab-colored powders, obtained chiefly from the flowers of two plants—Chrysanthemum (Pyrethrum) roseum, with rosy flowers, a native of the Caucasus, and yielding the Persian insect powder (Persian pellitory, Guirila); and Chrysanthemum cinerariaefolium, Visiani, with white flowers, yielding Dalmatian insect powder.
The Persian insect powder is now almost entirely displaced in commerce by the superior Dalmatian powder, which is exported from Trieste. When well kept, free from moisture, the powder retains its activity for years. The mode of its cultivation and collection, in Dalmatia, is jealously guarded as a secret. The powder destroys aphides, house flies, mosquitoes, and, in the form of a dust spray, is applied to keep insects from hot-house plants. The powder, in order to be effectual, must come into actual contact with the insect. The class of hemiptera (true bugs) spiders, hairy caterpillars, and other insects, are proof against it (Kew Bulletin, through Pharm. Jour. Trans., Vol. VII, 1898, p. 505). Insect powders are considerably subject to adulterations. A bright-yellow color indicates the presence of curcuma, fustic, chrome yellow, etc. (For detection, see W. L. Howie, Amer. Jour. Pharm., 1883, p. 361.) The addition of 10 per cent of powdered quillaja bark in commercial powder, while it produces sneezing in man, merely dilutes the powder with inert matter as far as its action on insects is concerned (Caesar and Loretz, 1898). Another adulteration consists in substitution by the Hungarian daisy. The latter yields 9.30 per cent of ash, while the flowers of C. cinerariaefolium yield only 6.5 per cent. (For botanical and chemical distinctions, see G. M. Beringer, Amer. Jour. Pharm., 1881), p. 1; also J. Schrenk, ibid., p. 295.) According to George R. Durrant (ibid., 1897, pp. 359-366), the insect powders of commerce are grossly adulterated. The toxic properties are due partly to volatile oil (0.5 per cent in picked specimens of closed flowers, less in open flowers), but principally to a soft acid resin, 4.8 per cent of which is found in selected closed, less than 4 per cent in half open, and still less in fully open flowers. The whole plant contains but traces. Admixture with the inert stems is recognized by the presence of chlorophyll—0.5 per cent of the latter was found in a mixture of flowers, but commercial powders yielded from 50 to 80 per cent of chlorophyll, referred to total ether extract. Thus the powders may be assayed by determining the weight of ether-extract obtainable therefrom; good powders should yield not less than 3.75 per cent of a pure yellow color and the pleasant and characteristic odor of the flowers. The best powders examined yielded 5.5 per cent of pure extract. Prof. J. M. Francis (Pharm. Jour. Trans., from Bull. of Pharm., Vol. XII, 1898, p. 5) contends that this standard of purity, while correct, is too strict, and would have the effect of increasing the price of the powders. Samples, of which one-third consists of stems, are stated to yield practically the same effect. (For a résumé of the chemical history of the powders, which is contradictory, probably owing to the difficulty of obtaining pure specimens, see G. R. Durrant, loc. cit.) A tincture of the flowers is said, by Maisch, to cause vesication like Rhus Toxicodendron. Insect powder is not poisonous to man, but, as stated above, is destructive to certain insect pests. It may be used in powder, in aqueous solution, and in fumigations. (For a list of less active plants, see H. Kalbruner, Amer. Jour. Pharm., 1875, pp. 25 and 399.)