Poke root is obtained from Phytolacca decandra, Linn. (N.O. Phytolaccaceae), a large herb widely distributed in Eastern and Central North America. It is official in the U.S.P. The drug occurs in transverse, oblique, or longitudinal slices of sparingly branched, nearly cylindrical roots, rarely exceeding 7 centimetres in diameter. The outer surface is yellowish or reddish-brown in colour, longitudinally wrinkled, and marked with narrow transverse bars of cork. The transverse section exhibits numerous concentric rings of narrow, fibrovascular bundles, alternating with rings of parenchymatous tissue; in longitudinal slices, the vascular strands are prominent, the intervening parenchyma being much contracted. Many of the pieces appear very fibrous from the separation and disintegration of the zones. The drug has no odour, but a sweetish taste, which afterwards becomes very acrid; the powder is a powerful sternutatory. The root should be collected in the autumn. Poke root closely resembles belladonna root, and the root of either Phytolacca decandra or an allied species has been-mixed with belladonna. It may be distinguished by its abnormal structure, and by the presence of acicular crystals of calcium oxalate in the place of the sandy crystals of belladonna root. It yields about 13 per cent of ash.
Constituents.—The drug appears to contain about 1 per cent. of a very bitter resin, 10 per cent. of a non-reducing sugar, and free formic acid. It has also been said to contain a crystalline neutral principle (phytolaccin), traces of an alkaloid (phytolaccine), and phytolaccic acid, together with tannin, gum, starch, etc.
Action and Uses.—Poke root is a slow-acting emetic, a purgative, and a mild narcotic, but its action has not been clearly ascertained, and the drug should be used with caution. It is employed in chronic rheumatism, usually in the form of liquid extract, which is also recommended as all application to inflamed and painful mammae. An ointment (1 in 8) has been used in tinea capitis and sycosis, and a strong infusion of the root has been recommended as a local application for piles. An eclectic resinoid, phytolaccin, is prepared and given in doses of 3 to 18 centigrams (1/2 to 3 grains) for rheumatism and syphilis.
Dose.—6 to 30 centigrams (1 to 5 grains) as an alterative; 1 gramme (15 grains) as an emetic.
- Fluidextractum Phytolaccae, U.S.P.—FLUIDEXTRACT OF PHYTOLACCA.
- Phytolacca, in No. 40 powder, 100; alcohol (49 per cent.), to 100. Average dose.—Emetic, 1 mil (15 minims); alterative, 1 decimil (0.1 milliliters) (1 1/2 minims).
- Tinctura Phytolaccae, B.P.C.—TINCTURE OF POKE ROOT. 1 in 10.
- Used empirically in chronic rheumatism. Dose.—2 to 6 decimils (0.2 to 0.6 milliliters) (3 to 10 minims).
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.