Related entry: Cascara sagrada
Rhamnus Cathartica. N. F. IV. Buckthorn Berries. Baccae Spinae Cervinae.—"The dried, ripe fruit of Rhammus cathartica Linné (Fam. Rhamnaceae), without the presence of more than 5 per cent. of the unripe fruit or other foreign matter." N. F.
The R. cathartica, Linn, or common buckthorn, grows in Europe along with R. Frangula, and has become naturalized in this country. Its bark is probably often sold for the official Frangula. It is distinguished by its more spreading, thorny habit, and its dioecious flowers, which are thickly clustered in the axils and have their parts in fours. The leaves are more acute, have their margins finely serrate and their lateral veins mostly proceeding from the proximal half of the midrib. The fruit is black.
The berries which are ripened in September, are of the size of a pea, round, somewhat flattened at top, black, smooth, shining, with four seeds in a green, juicy parenchyma. Their odor is unpleasant, their taste bitterish, acrid, and nauseous. Their blackish, expressed juice was formerly recognized in the Br. Ph. under the name of Rhamni succus.
It is reddened by the acids, and from deep green is rendered light by the alkalies. Upon standing it soon begins to ferment, and becomes red in consequence of the formation of acetic acid. Evaporated to dryness, with the addition of lime or an alkali, it forms the color called by painters sap-green. The dried fruit of another species, R. infectoria, yields a rich yellow color, and is employed in the arts under the name of French berries.
The National Formulary IV describes buckthorn berries as follows: "Flattened, globoid or ovoid, from 4 to 8 mm. in diameter; externally purplish-black, wrinkled from shrinking of the mesocarp in drying; three-to four-celled, each cell containing a brown, triangular-convex, seed-like nutlet; in the fully dried, ripe fruit the pedicel is usually lacking. Odor faint, unpleasant; taste at first sweetish, then nauseating and bitter; it colors the saliva purplish-red. When macerated in water the drupe readily assumes its original globular shape, about 1 cm. in diameter. The expressed pulp is colored red by acids and greenish-yellow by alkalies. Shake out an aqueous infusion of Rhamnus Cathartica with ether, separate the ethereal solution and shake it with 5 per cent. ammonia water; the ammonia solution assumes a cherry-red color. The unripe fruit, which is to be rejected, is green to greenish-brown, firm, furrowed, pedicel usually attached; very bitter; it colors the saliva greenish-yellow. Rhamnus Cathartica yields not more than 5 per cent. of ash." N. F.
The blackish, expressed juice of Buckthorn berries was formerly recognized in the Br. Ph. under the name of Rhamni Succus. It has the color, odor, and taste of the parenchyma, is reddened by the acids, and from deep green is rendered light green by the alkalies. Upon standing it soon begins to ferment, and becomes red in consequence of the formation of acetic acid. Evaporated to dryness, with the addition of lime or an alkali, it forms the color called by painters sap-green. The dried fruit of another species, R. infectoria, yields a yellow color, and is employed in the arts under the name of French berries.
Tschirch and Polacco, in 1900, investigated the constituents of buckthorn berries and found certain yellow coloring substances. The researches of N. Waljaschko and N. Krassowski since demonstrated that the fruits of R. cathartica contain the same yellow coloring matters as are contained in the fruits of R. infectoria and R. tinctoria, namely, quercetin and rhamnin, both existing in R. cathartica in the form of glucosides, which are split up by the action of an enzyme contained in the fruits: Rhamnin, for example, from the glucoside xanthorhamnin. The yellow coloring matters of Tschirch and Polacco, therefore, cannot be regarded as pure substances. They also extended the investigations of the former concerning the purgative substances contained in buckthorn fruits, with results confirming the theory advanced by Tschirch. They found the fruits to contain about 2 per cent. of emodin-substances and as cleavage products of the glucosides obtained by the action of ferments from the emodin-substances: Emodin, identical with frangula emodin and rhamnosid; the emodin of rhamnoxanthin (C21H20O8 + H2O), which is isomeric but not identical with frangulin; rhamnonigrin, and a resin like body containing emodin. Other constituents found in buckthorn berries are: fixed oil, succinic acid, glucose, galactose, rhamnose, and a pentose, but of the four sugars only glucose was present in the free state, the others being derived from the glucosides. (Ph. Ztg., 1909, No. 16, 159.) Tschirch and Bromberger (Schw. Woch. f. Ch. v. Ph., 1912, p. 193) report the following constituents found in a 15 Kilo sample upon which they did considerable work: Rhamnosterin, C18H28O2; rhamnofluorin, C14H12O6; emodin, C15H10O2; iso-emodin, C15H10O5; chrysophanol (C14H5O2)CH3(OH)2. A fluidextract and a syrup of buckthorn berries are contained in the N. F.
The dose of the dried berries is from ten to twenty grains (0.65-1.2 Gm.). Among other species of Rhamnus which have claimed attention are R. Wightii, W. & A., a common shrub of Madras and Bombay (P. J., Feb., 1888), and R. californica, Eschsch. (R. humboldtiana, Roem. and Schult., of Mexico, which S. E. Sosa states sometimes produces paralysis in children (El Estudio, 1890). (See also Cascara Sagrada.)
The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.