Pyrethri Radix, B.P. Pyrethrum Root.
Related entry: Pyrethrum flowers
Pyrethrum, or pellitory, root (Pyrethum, U.S.P.), is obtained from Anacyclus Pyrethrum, DC. (N.O. Compositae), a small plant indigenous to Algeria, being collected in the autumn and dried. The root is simple, from 5 to 10 centimetres long, and about 12 millimetres in thickness, tapering towards the tip, and often also towards the crown, where a tuft of greyish hairs can usually be seen. The external surface is brown, and longitudinally furrowed. The root is tough, but breaks with a short fracture, the fractured surface exhibiting a conspicuously radiate structure, narrow yellowish wedges of wood alternating with whitish medullary rays. Numerous yellow or brown oil glands occur both in the cortex and medullary, rays. The root yields from 4 to 6 per cent. of ash. The odour is characteristic; the taste, pungent, producing a copious flow of saliva. The root of Corrigiola telephiifolia, Pour. (N.O. Illecebraceae), is not infrequently found in commercial pellitory root, occasionally in considerable quantity. The root resembles pellitory very closely, but may be distinguished by the warty protuberances with which it is crowned, and by the section which exhibits three or four concentric circles, that of pellitory being radiate. It is devoid of the pungent taste of pellitory.
Constituents.—The chief constituent is a colourless, crystalline alkaloid, pyrethrine (also called pellitorine), which is apparently allied to piperine; it possesses an intensely pungent taste, and produces the sialagogue effect. Pyrethrum root also contains about 50 per cent. of inulin, and traces of volatile oil.
Action and Uses.—Pyrethrum root is used as a masticatory, and in the form of lozenge for its reflex action on the salivary glands in dryness of the mouth and throat. The tincture is applied on cotton wool, or rubbed along the gums in toothache, and for this purpose may with advantage be mixed with camphorated chloroform.
Dose.—1 to 2 grammes (15 to 30 grains).
PREPARATIONS.
- Tinctura Pyrethri, B.P.—TINCTURE OF PYRETHRUM. Syn.—Tincture of Pellitory.
- Pyrethrum root, in No 40 powder, 20; alcohol (70 per cent.), sufficient to produce 100. Add 15 of the alcohol to the drug to moisten it and complete the percolation process.
- Tinctura Pyrethri, U.S.P.—Similar to B.P., but made with alcohol (95 per cent.).
