The dried bark.
Habitat. Europe, N. Asia; hedges, bushy places.
Rham'nus. L. see etymology, page 384, of Rhamnaceae.
Frang'u-la. L. fr. frango, frangere, to break - i. e., from its brittle stems - its medieval name.
Plant. - Slender, straggling bush, 3-4.5 M. (10-15°) high; branches not terminating in spines, not thorny; leaves oval, entire, 2.5-6 Cm. (l-2 2/5') long, rounded at base, pointed at apex; flowers May-June,
Fig. 249. - Rhamnus Frangula: bark, natural size.
Fig. 250. - Frangula bark: transverse section, magnified 80 diam.
greenish to whitish-pink; fruit July, berry size of a pea, green, then white, pale yellow, pink, red, finally black, 2-3-seeded. Bark, in quills of variable length, frequently flattened, crushed, .5-1 Mm. (1/50-1/25) thick, purplish-black with many prominent, lighter-colored transverse lenticels and occasional patches of foliaceous lichens bearing small, blackish apothecia; inner surface smooth, dark brown with occasional purplish blotches, longitudinally striate, red with solutions of alkalies; fracture short, inner layer slightly fibrous; odor distinctive; taste slightly bitter. Powder, yellowish-brown; microscopically - no stone cells (dif. from R. Purshiana); fragments of parenchyma, 25 cork, numerous rosette aggregates of calcium oxalate and starch grains .003 Mm. (1/8325') broad, cells of parenchyma, bast-fibres, medullary rays. Tests: 1. Shake occasionally until cold .1 Gm. with hot distilled water 10 Ml. (Cc.), filtrate + few drops of ammonia water - deep red. 2. Macerate .1 Gm. with 10 drops of alcohol, boil with distilled water 10 Ml. (Cc), cool, filter, shake filtrate with ether 10 Ml. (Cc); shake 3 Ml. (Cc.) of the yellow, separated ethereal solution with 3 Ml. (Cc.) of ammonia water - ammoniacal solution + distilled water 20 Ml. (Cc.), remains cherry-red. Solvent: diluted alcohol. Dose, 3ss-l (2-4 Gm.).
Adulterations. - Barks of allied species, especially R. camiol'ica, the bark of which is thicker, grayish, longitudinally wrinkled, numerous lenticels, but smaller, obscured and less prominent, bitter, astringent, medullary rays 4-7 cells wide.
Commercial. - Obtain bark in the spring from young trunks and large branches, dry carefully; should not be taken from old trunks, as that has different taste and characteristics. The emetic action of green bark is due to a hydrolytic ferment, which is destroyed either by aging or moderately heating (38° C; 100° F. for 48 hours). Owing to its various European names - black alder, aune noir, schwarzerle, etc. - it is likely to be confused with the genus Alnus, to which more properly such names belong.
Constituents. - Frangulin (rhamnoxanthin) .04 p. c, Emodin 1-3.8 p. c, Isoemodin, frangulic acid, chrysophan, resin, tannin, ash 5-6 p. c
Frangulin, C21H20O9. - Glucoside, obtained by macerating bark 4 days in carbon disulphide; evaporate, exhaust residue with alcohol, leaving fat behind, evaporate alcoholic solution to dryness, crystallize from ether. It is in yellow crystals, sublimable, insoluble in water, slightly soluble in cold alcohol and ether, soluble in hot fixed oils, hot alcohol, benzin, turpentine, purple by alkalies; dyes cotton, silk, wool, etc., yellow; with hydrochloric acid yields glucose and frangulic (frangulinic) acid, by hydrolysis yields emodin and rhamnose, C6H12O5, while emodin + rhamnose = frangulin + water; thus, (1) C21H20O9+ H2O = C15H10O5 + C6H12O5, or (2) C15H10O5 + C6H12O5 = C21H20O9 + H2O.
Isoemodin, C15H8O4. - Bitter and laxative; fresh bark yields neither frangulin nor emodin, as these develop by age.
Frangulic (Frangulinic) Acid, C14H8O4 - Glucoside, obtained by boiling alcoholic solution of frangulin with hydrochloric acid; yellowish-brown crystals, aperient like cathartic acid.
Preparations. - 1. Fluidextractum Franguloe. Fluidextract of Frangula. (Syn., Fldext. Frangul., Fluid Extract of Frangula, Fluid-extract of Buckthorn Bark; Extractum Rhamni Frangulae Liquidum; Fr. Extrait fluide de Bourdaine; Ger. Faulbaumrindenfluidextrakt.)
Manufacture: Similar to Fluidextractum Tritici, page 91 ; evaporate to 75 Ml. (Cc), cool, add alcohol 25 Ml. (Cc.), and, if necessary, water q. s. 100 Ml. (Cc.). Dose, 3ss-l (2-4 Ml. (Cc.)).
Fig. 251. - Rhamnus cathartica: 1-3, the imperfect pistillate and staminate flowers; 2, stamens - s, fertile, a, sterile; 4, f, fruit; g, cross-section of fruit.
Unoff. Preps.: Decoction, 5 p. c., dose, ℥ss-1 (15-30 Ml. (Cc.)). Extract, dose, gr. 2-8 (.13 - .5 Gm.). Ointment. Elixir Catharticum Compositum, fldext. 12.5 p. c, fldext. senna 10, fldext. rhubarb 6.2, + .
Properties. - Purgative, tonic, diuretic. When fresh, emetic, severe intestinal irritant, causing much pain, but when modified by age resembles rhubarb or senna, though milder.
Uses. - In dropsy, costiveness, constipation of pregnancy (fluid-extract, exx (1.3 Ml. (Cc.)) ter die). Ointment of fresh bark for parasitic skin affections (itch, etc.).