Pruni Virginianae Cortex, B.P. Virginian Prune Bark.
Virginian prune bark, or more correctly, wild cherry bark (Prunus Virginiana, U.S.P.; Wild Cherry), is obtained from the wild or black cherry, Prunus serotina, Ehrh. (N.O. Rosaceae), a tree widely distributed in America. The bark is collected in file autumn, when it is most active, preferably from young stems and branches, it occurs in flattened, curved, or recurved pieces, about 2 millimetres in thickness, sometimes 12 centimetres long and 5 centimetres broad, but usually smaller. The young bark is often covered with a thin, smooth, glossy, reddish-brown cork, marked with tangentially elongated, whitish lenticels, which can easily be removed in thin strips, disclosing the greenish-brown cortex. On the inner surface, the bark is of a cinnamon-brown colour, with fine longitudinal striations. The fracture is short and granular, the fractured surface being of a reddish-grey colour, and exhibiting numerous pale red medullary rays, alternating with bast rays. The odour of the bark, which is intensified on moistening, resembles that of bitter almonds; the taste is similar, and also bitter and slightly astringent. On incineration, the bark yields from 3 to 6 per cent. of ash. The bark of other North American species of Prunus is occasionally sold as Virginian prune bark. The genuine is well characterised by the presence of stone cells and absence of bast fibres, by the short granular fracture and by the characteristic taste. Other prune barks are more astringent, more fibrous, and devoid of the bitter almond taste.
Constituents.—The drug contains l-mandelonitrile glucoside and an enzyme, which interact in the presence of water and yield benzaldehyde, hydrocyanic acid, and dextrose. Benzoic, trimethylgallic and p-coumaric acids and a small amount of essential oil are present. Other constituents are tannin, a phytosterol, fatty acids and resinous materials, which yield β-methylaesculetin on hydrolysis with acid. Good specimens of drug yield from 0.12 to 0.16 per cent. of hydrocyanic acid. The bark also contains a bitter, crystalline glucoside to which the bitter taste is due, and tannin, together with starch, etc. Young bark is more active than the thick bark from old stems.
Action and Uses.—Preparations of wild cherry bark are employed as mild sedatives to relieve cough; their action is generally credited to the small quantity of hydrocyanic acid they contain. A tincture and syrup are prepared, the latter is a pleasant flavouring agent for cough mixtures.
Dose.—1 to 2 grammes (15 to 30 grains).
- Fluidextractum Pruni Virginianae, U.S.P.—FLUIDEXTRACT OF WILD CHERRY.
- Virginian prune bark, in No. 30 powder, 100; glycerin, 20; alcohol (20 per cent.), sufficient to produce 100. Added to cough syrups and mixtures for its mildly sedative properties. Average dose.—2 mils (30 minims).
- Infusion Pruni Virginianae, U.S.P. and B.P.C.—INFUSION OF VIRGINIAN PRUNE. Syn.—Infusion of Wild Cherry.
- Virginian prune bark, in No. 20 powder, 4; glycerin, 5; distilled water, sufficient to produce 100. This infusion may be used when a weaker preparation than Tinctura Pruni Virginianae is desired, or as an addition to cough mixtures. Dose.—30 to 60 mils (1 to 2 fluid notices).
- Syrupus Pruni Virginianae, B.P.—SYRUP OF VIRGINIAN PRUNE. Syn.—Syrup of Wild Cherry.
- Virginian prune bark, in No. 20 powder, 15; refined sugar, in coarse powder, 75; glycerin, 6.25; distilled water, sufficient to produce 100. Add sufficient distilled water to the powdered bark to moisten it thoroughly, macerate for twenty-four hours, then transfer to a percolator, and allow to percolate slowly until the product measures 45. Dissolve the sugar in the percolate without the aid of heat, add the glycerin, mix, strain, and pass sufficient distilled water through the strainer to make up to the required volume. Syrup of Virginian prune is a sedative for use in the cough of phthisis and in chronic bronchitis. Dose.—2 to 4 mils (½ to 1 fluid drachm).
- Syrupus Pruni Virginianae, U.S.P.—Similar to B.P., but contains 15 of glycerin, and only 70 of sugar in 100 by volume.
- Tinctura Pruni Virginianae, B.P.—TINCTURE OF VIRGINIAN PRUNE. Syn.—Tincture of Wild Cherry.
- Virginian prune bark, in No. 20 powder, 20; alcohol, 62.5; distilled water, 37.5. Add the powdered bark to the distilled water, mix and set the mixture aside for twenty-four hours: then add the alcohol and complete the maceration process. Tincture of Virginian prune bark is a mild sedative for use in cough and bronchitis. Dose.—2 to 4 mils (½ to 1 fluid drachm).