544. Colocynthidis pulpa.—Colocynth
The dried pulp of the fruit, Citrul'lus colocyn'this Schrader, containing not more than 5 per cent. of seeds nor more than 2 per cent. of epicarp. U.S.P. IX.
BOTANICAL CHARACTERISTICS.—Stem procumbent, angular, hispid; leaves cordate-ovate, lobate; tendrils short. Flowers axillary, female flowers solitary, petals yellow with greenish veins. Fruit globose, smooth, 6-celled, with very bitter pulp; seeds whitish, sometimes brownish.
HABITAT.—Asia, Europe, and Africa.
DESCRIPTION OF DRUG.—The fresh fruit has a marbled green surface, not very unlike the watermelon. It has a thick rind inclosing a white, spongy pulp, imbedded in which are numerous light-colored seeds. The fruit on drying loses about go per cent. of water, leaving a very light, spongy, white or yellowish-white pulp, which, deprived of the seed, constitutes the official drug. Colocynth "apples," as they appear in the market, contain the seeds, but are deprived of the rind; 50 to 100 mm. (2 to 4 in.) in diameter. A cross-section of the spherical pulp ("apples") makes apparent three distinct wedges, each of which has two branches; this structure is due to the parietal placentae, which project to the center of the fruit, then divide and turn back, making convoluting branches directed one toward the other. In odorous; so intensely bitter that the bitterness is imparted to any object brought in contact with it.
Powder.—Microscopical elements of: See Part iv, Chap. I, B.
CONSTITUENTS.—Resin, gum, and amyloid principles. Colocynthin, C56H84O23, a yellowish, somewhat translucent, bitter, and friable glucoside, is, perhaps, the most important constituent; it is contained in the pulp to the extent of about 2 per cent. Colocynthin is a taste less crystalline principle left after treating the alcoholic extract with cold water in preparing colocynthin. Ash, not to exceed 15 per cent.
The powder should not yield more than 2 per cent. of fixed oil when treated with petroleum benzin—a check test on the 5 per cent. limit of seeds. U.S.P. IX.
Preparation of Colocynthin.—Exhaust alcoholic extract with water, precipitate with lead acetate and subacetate, remove lead from liquid by treating with H2S, filter, then precipitate with tannin; suspend the tannate in alcohol, decompose with lead hydroxide, remove excess of lead by H2S, filter and evaporate, and wash the residue with ether.
ACTION AND USES.—A powerful hydragogue cathartic, given in combination with weaker purgatives. Dose: 3 to 10 gr. (0.2 to 0.6 Gm.).
- OFFICIAL PREPARATIONS.
- Extractum Colocynthidis, Dose: ½ to 2 gr. (0.0324 to 0.13 Gm.).
- Extractum Colocynthidis Compositum (Extract Colocynth 16 per cent., with aloes, scammony, cardamon and soap), 5 to 25 gr. (0-3 to 1.6 Gm.).
- Pilulae Catharticae Compositae (8 per cent. of compound extract) 2 to 5 pills.
