Phytolacca. Poke root. Phytolacca decandra. Phytolacca acinosa.
Phytolacca. N. F. IV (U. S. P. VIII). Poke Root. Phytolaccae Radix. Phytolacca Root. Racine de Phytolaque, Fr. Kermesbeerenwurzel, G.—"The dried root of Phytolacca decandra Linné (Fam. Phytolaccaceae), collected in the autumn." N. F.
The U. S. P. has in the past recognized both the root and the berries of the Phytolacca decandra L. This is an indigenous plant, with a large, branching, perennial root, often 20 to 25 cm. in diameter, which is fleshy, fibrous, whitish within, and covered with a thin brownish cork. The stems, which are annual, frequently grow to the height of 6 to 15 dm., and divide into numerous spreading branches, which are green when young, but becoming purple especially in the upper portions after the berries have ripened. The leaves are alternate, ovate-oblong, entire, pointed, smooth ribbed beneath, and on short foot-stalks. The flowers are small and in long racemes. The raceme of flowers becomes a cluster of dark purple, almost black, shining berries flattened above and below, and divided into ten loculi, each containing one seed.
Poke is abundant in all parts of the United States, flourishing along fences, by the borders of woods, in newly cleared fields, and especially in the muck thrown up from the ditches or swamps. It also grows spontaneously in Northern Africa and Southern Europe, where, however, it is supposed to have been introduced from America. Its flowers begin to appear in July, and the fruit ripens in autumn. The magnitude of the poke weed, its large rich leaves, and its beautiful clusters .of purple berries, often mingled upon the same branch with the green unripe fruit and the flowers still in bloom, render it one of the most striking of our native plants. The young shoots are much used as food early in the spring, boiled in the manner of asparagus. The ashes of the stems and leaves yield, according to Braconnot, not less than 4.2 per cent. of potassium hydroxide. In the plant the potassium is combined with an acid resembling malic acid. The leaves, berries, and root are used in medicine, but the latter is the most active. It should be dug up late in November, cut into thin transverse slices, and dried with a moderate heat. As its virtues are diminished by keeping, a new supply should be procured every year. The berries should be collected when perfectly ripe, and the leaves about the middle of the Bummer, when the foot-stalks begin to redden.
The berries (Phytolaccae Fructus, U. S., 1890, Phytolaccae Baccae, U. S., 1880, Poke Berry) contain a succulent pulp, and yield upon pressure a large quantity of fine purplish, red juice. They have a sweet, nauseous, slightly acrid taste, with little odor.
The dried root is "cylindrical, somewhat tapering, sparingly branched, from 3 to 7 cm. in thickness, mostly in transverse or longitudinal slices; externally yellowish-brown, finely longitudinally or spirally wrinkled and thickly annulate with lighter colored, low ridges; fracture fibrous, characterized by alternating layers of fibro-vascular tissue and parenchyma, the layers of the latter being much retracted. Odor slight; taste sweetish, afterwards highly acrid. Phytolacca yields not more than 14 per cent. of ash." N. F.
From the analysis of Edward Donnelly, the root appears to contain tannic acid, starch, gum, sugar, resin, fixed oil and lignin, besides various inorganic substances. (A. J. P., xv, 169.) Claussen (Pharm., 1879, p. 466) prepared from the seeds of Phytolacca decandra, by extraction with alcohol, evaporation to dryness, and taking up with chloroform or ether, after washing the residue with petroleum benzin, a neutral principle in silky lustrous crystals, insoluble in water, soluble in alcohol, ether, and chloroform, which he named phytolaccin. A. Tereil (C. R. A. S., 91, 856) obtained from the berries an acid (phytolaccic acid) as an uncrystallizable yellowish-brown mass of gummy consistency. It was soluble in water and alcohol, slightly soluble in ether, of acid reaction, and gelatinizing with hydrochloric and sulphuric acids. W. F. Wagner (A. J. P., 1887, p. 69) found tannin in the berries, but not in the root. W. A. Partee (A. J. P., 1888, p. 123) made a proximate examination of poke root and found crystals deposited from a solution of an alcoholic extract in absolute alcohol; he also discovered traces of tannin, glucose, and indications which pointed to the presence of a glucosidal principle. Frankforter and Ramaley (A. J. P., 1897, 281) have again analyzed the root with care. They find nearly 10 per cent. of a non-reducing sugar, free acid, identified as formic acid, but no certain proof of either alkaloid or glucoside. The very bitter resin amounted to 1 per cent.; phytolaccine, an alkaloid, has been said to exist in minute quantities in the root.
Uses.—Phytolacca is emetic, purgative and somewhat narcotic. As an emetic it is very slow in its operation, frequently not beginning to cause vomiting in less than one or two hours after it has been taken, and then continuing to act for a long time upon both the stomach and the bowels. The vomiting produced by it is said not to be attended with much pain or spasm, but narcotic effects have been observed by some physicians, such as drowsiness, vertigo, and dimness of vision. In overdoses it produces excessive vomiting and purging, attended with great prostration of strength, and sometimes with convulsions, and has, in several instances, proven fatal. According to Robert Bartholow, phytolacca causes in the lower animals convulsions and death from paralysis of respiration. It is not fit for use as an emetic, but has been employed as an alterative in chronic rheumatism, granular conjunctivitis, and even in cancer. Locally it has been used in the form of ointment (a drachm to the ounce) in the treatment of psora, tinea capitis, sycosis, and favus. It occasions at first a sense of smarting and heat in the parts to which it is applied. Alcohol, diluted alcohol, and water, extract the virtues of the poke root. A fluidextract is included in the National Formulary.
Dose, emetic, ten to thirty grains (0.65-2.0 Gm.), alterative, one to five grains (0.065-0.32 Gm.).
Phytolacca Acinosa Roxb. (Fam. Phytolaccaceae.)—This plant has long been used in Japan as a diuretic, and is said to be violently poisonous. C. Nagai has separated from it an amorphous resin, phytolaccotoxin, which appears to be a spinal convulsant, and at the same time stimulant to the circulation, probably through the vasomotor centers. (Sei-i-kwai. Med. Journ., April, 1891.)