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Prunus Virginiana. U. S. (Br.)

Prunus Virginiana. U. S. (Br.)

Wild Cherry. Prun. Virg. [Wild Black Cherry Bark]

"The stem-bark of Prunus serotina Ehrhart (Prunus virginiana Miller) (Fam. Rosaceae), collected in autumn and carefully dried. Preserve Wild Cherry in tightly-closed containers, protected from light." U. S. "Wild Cherry Bark is the bark of Prunus serotina, Ehrft., collected in autumn." Br.

Pruni Virginianae Cortex, Br., Wild Cherry Bark; Virginian Prune Bark; Rum, Whisky, or Cabinet Cherry, Wild Black Cherry; Ecorce de Cerisier de Virgiuie, Fr.; Wildkirschenrinde, Amerikanischer Zierstrauch, G.

The genus Prunus now includes the plums, almonds, peaches, apricots, and cherries, and comprises about one hundred and twenty species. They are generally distributed in the temperate regions of the northern hemisphere. In the United States there are about forty indigenous species.

The name P. virginiana was applied by Miller (Diet., ed. 8, No. 3), and not Linnaeus, to P. serotina Ehr. P. virginiana L., commonly called wild cherry or choke cherry, is distinguished from P. serotina Ehr., known more properly as wild black cherry, by the following characteristics: P. virginiana L. has deciduous calyx lobes; oblong-obovate pointed endocarp (or stone); leaves broadly oval to oblong-obovate, and usually abruptly acuminate; inner bark with a rather disagreeable odor. P. serotina Ehr. has persistent calyx lobes; the endocarp (or stone) oblong-obovate, usually gradually acuminate; leaves oblong or lanceolate-oblong, usually gradually acuminate; the inner bark and leaves possess an aromatic odor. The British name, "Virginian Prune Bark," for the bark is misleading; Virginian Peach Bark or Virginian Almond Bark would have been no more of a misnomer. The official species is, according to Michaux, one of the largest productions of the American forest. Trees were observed by that botanist on the banks of the Ohio, from eighty to one hundred feet high, with trunks from twelve to fifteen feet in circumference, and undivided to the height of twenty-five or thirty feet. But as usually met with in the Atlantic States the tree is much smaller. In the open fields it is less elevated than in forests, but sends out more numerous branches, which expand into an elegant oval summit. The trunk is regularly shaped, and covered with a rough blackish bark, which detaches itself semicircularly in thick narrow plates. The leaves are alternate, oval-oblong, or lanceolate-oblong, acuminate, unequally serrate, smooth on both sides, of a beautiful brilliant green; the petioles are furnished with one or more reddish conspicuous glands. The flowers are small, white, and occur in long-erect or spreading racemes. They appear in May, and are followed by globular drupes, about the size of a pea, and when ripe of a shining blackish-purple color. For a paper on the structure of species of Prunus, by E. S. Bastin, see Proc. A. Ph. A., 1895, 211.

This tree is distributed from Ontario south to Florida, and westward to Dakota, Nebraska, Kansas, Indian Territory, and Eastern Texas. It extends along the mountain ranges of Western Texas, Mexico, and Pacific regions of Central America, Colombia, and Peru. In the United States it was once common throughout the Appalachian region. In the neighborhood of Philadelphia it affects open situations, growing solitarily in the fields and along fences, and seldom aggregated in woods or groves. It is highly valued by the cabinet-makers for its wood, which is compact, fine-grained, susceptible of polish, and of a light red tint which deepens with age. The leaves have been found by Procter to yield volatile oil and hydrocyanic acid on distillation, and in such proportion that a water distilled from them might with propriety be substituted for the cherry-laurel water. (Proc. A. Ph. A., 1858, 325.) The fruit has a sweetish, astringent, bitter taste, and is much used in some parts of the country to impart flavor to spirituous liquors. The bark is obtained indiscriminately from all parts of the tree, though that of the roots is thought to be most active. The revisers of the Pharmacopoeia believe with J. S. Perot that the bark is stronger when collected in autumn than in the spring; from a portion gathered in April Perot obtained 0.0478 per cent. of hydrocyanic acid, and from another in October 0.1436 per cent., or about three times as much. (A. J. P., xxiv, 111.) The bark should be preferred recently dried, as it deteriorates by keeping. A. B. Stevens (Proc. A. Ph. A., 1895, 226; 1896, 215), after testing many specimens, reached the conclusion that bark procured from different parts of the same tree varied in the yield of hydrocyanic acid, the value being in this order: 1, root; 2, twigs; 3, trunk; the bark from young trees yielding more glucoside than that from old trees. Jos. L. Lemberger (A. J. P., 1872, 303) believes that tannic acid is most abundant in the bark in October and November. On the other hand, Grace E. Cooley (A. J. P., August, 1897) concludes that there is more tannic acid in the bark during the active growth of the spring than in the autumn. She further states that in the spring and autumn the bark contains its maximum percentage of starch; so that if the bark, whether powdered or whole, contains much starch in its parenchymatous cells, it has been collected after the time of leaf-fall in the autumn or before the unfolding of the leaves in the spring. Occasionally barks find their way into commerce as Prunus Virginiana which yield no odor of hydrocyanic acid when moistened and are probably obtained from other than the official wild cherry. (See Bastin, A. J. P., 1895, and Finnemore, P. J., 72.)

Moser points out that collectors frequently mistake P. virginiana L. or choke cherry for P. serotina Ehrh. or black cherry, which is the official source of wild cherry bark. He presents a description of the two trees and of the characteristic features of their barks. (A. J. P., 1909, lxxxi, p. 579.) Farwell reports that the bark of P. demissa (Nutt.) Walpers, a tree from west of the Rocky Mountains, has been found in commerce. It is much darker and the lenticels are much more prominent. The preparations made from it resemble the official wild cherry bark in color, odor and taste.

Properties.—Wild cherry bark is officially described as follows: "Usually in transversely curved pieces from 2.5 to 8 cm. in length and from 0.5 to 4 mm. in thickness; outer surfaces light brown or greenish-brown, smooth, except for numerous lenticels from 3 to 4 mm. in length; inner surfaces light brown, longitudinally striate and occasionally fissured; fracture short, granular; odor distinct, bitter almond-like when macerated in water; taste astringent, aromatic, and agreeably bitter. Under the microscope, sections of Wild Cherry show a tendency for the separation in radial segments or bands of the phloem tissues from the rather broad medullary rays; periderm usually of a few layers of cells; outer bark from young twigs with 1 or 2 nearly continuous layers of cells, the latter being of very irregular shape, often branching and with thick lamellated, porous walls; medullary rays extending in more or less scythe-shaped groups from the cambium to the outer bark, from 1 to 10 cells in width, some of the cells occasionally being modified to stone cells; between the medullary rays occur numerous small groups of stone cells, resembling those of the outer bark and occasionally modified to sclerenchymatous fibers; calcium oxalate mostly in crystal fibers consisting of monoclinic prisms, from 0.015 to 0.04 mm. in diameter, also in rosette aggregates from 0.01 to 0.04 mm. in diameter; starch grains numerous, occurring in the medullary rays and parenchyma. The powder is light brown; when examined under the microscope it exhibits bast-fibers and stone cells with thick, strongly lignified walls; crystal fibers with monoclinic prisms and rosette aggregates of calcium oxalate, from 0.01 to 0.04 mm. in diameter; starch grains nearly spherical, from 0.003 to 0.004 mm. in diameter." U. S.

"In curved pieces or irregular fragments not more than three millimetres thick. Frequently covered with a smooth, thin, reddish-brown, papery cork, or, if this has been removed, exhibiting a greenish-brown cortex; marked with transversely elongated lenticels. Fracture short, granular; fractured surface reddish-grey. Inner surface reddish-brown, striated or reticulately fissured. In the bark numerous groups of sclerenchymatous cells of characteristic shape, but no typical bast fibers; in the parenchymatous cells minute starch grains and prismatic crystals of calcium oxalate. Slight odor; taste astringent, aromatic and bitter, recalling that of bitter almonds." Br.

In the fresh state, or when treated with water, it emits an odor resembling that of peach leaves. Its taste is agreeably bitter and aromatic, with the peculiar flavor of the bitter almond. It imparts its sensible properties to water, either cold or hot, producing a clear reddish infusion closely resembling Madeira wine in appearance. Its peculiar flavor and its medicinal virtues are injured by boiling, in consequence partly of the volatilization of the principles upon which they depend, partly upon a chemical change effected by the heat. From an analysis by Stephen Procter, it appears to contain starch, resin, tannin, gallic acid, fatty matter, lignin, red coloring matter, salts of calcium, potassium, and iron. He obtained also a volatile oil, associated with hydrocyanic acid, by distilling the same portion of water successively from several different portions of the bark. William Procter proved that, as in the case of bitter almonds, the volatile oil and hydrocyanic acid do not exist ready formed in the bark, but are the result of the reaction of water with amygdalin, which he ascertained to be one of its constituents. In order, however, that this change may take place, he affirmed that the agency of another principle, probably analogous to, if not identical with, emulsin or the synaptase of Robiquet, was also essential, and, as this principle becomes inoperative at the boiling temperature, one can understand how decoction may interfere with the virtues of the bark. (A. J. P., x, 197.) The bitterness appears to be due to the fluorescent substance described below which confirms Procter, who found the bitterness of an extract of the bark to remain after it had been wholly deprived of amygdalin. Stevens and Judy (A. J. P., 1895, 482, 534) found that the thick bark contains more amygdalin and consequently yields more HCN than the thin bark. The thick bark contains amygdalin, etc., 4.12 per cent., and HCN from 0.32 to 0.35 per cent.; the thin bark, amygdalin, etc., 3.16 per cent., and HCN from 0.24 to 0.27 per cent. F. B. Power and Henry Weimer, on the other hand, state that the bark does not contain crystallizable amygdalin, that the ferment principle is not emulsin, and that it cannot be isolated by an analogous process. The bitter principle, which appears to be the fluorescent substance, has the character of a glucoside, and crystallizes in colorless needles. (West. Drug., 1887, p. 331.)

R. Rother (A. J. P., 1887, p. 286), in searching for the fluorescent principle of wild cherry bark, obtained a reddish crystalline substance, soluble in water, chloroform, ether, and alcohol, the solution of which fluoresced strongly on addition of ammonia. Bother says that it does not agree in crystalline form with mandelic acid, but may be a derivative of it.

Uses.—Wild cherry bark has the stomachic effects of the simple bitters but is comparatively infrequently employed for this purpose. On the theory that hydrocyanic acid is a cough sedative, wild cherry bark has been popularly employed in the treatment of bronchitis of various types, but is of doubtful service.

Dose, from thirty to sixty grains (2.0-3.9 Gm.).

Off. Prep.—Syrupus Pruni Virginianae, U. S., Br.; Tinctura Pruni Virginianae, Br.; Elixir Taraxaci Compositum (from Fluidextract), N. F.; Emulsum Olei Morrhuae cum Pruno Virginiana (from Fluidextract), N. F.; Fluidextractum Pruni Virginianae, N. F.; Infusum Pruni Virginianae, N. F.; Syrupus Cimicifugae Compositus, N. F.; Syrupus Pint Strobi Compositus, N. F.; Syrupus Pint Strobi Compositus cum Morphinae, N. F.; Vinum Pruni Virginianae, N. F.; Vinum Prunus Virginianae Ferratum (from Wine), N.F.

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

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