"The fruit of Cassia Fistula, Linné" (U. S. P.) (Bactyrilobium Fistula, Willdenow; Cathartocarpus Fistula, Persoon).
COMMON NAME AND SYNONYM: Purging cassia; Fructus cassiae fistulae.
ILLUSTRATION: Bentley and Trimen, Med. Plants, 87.
Botanical Source.—Cassia fistula is a tree growing from 20 to 40 feet high, with many spreading branches toward the summit. The wood is hard and heavy. The leaves pinnate, alternate, from 12 to 18 inches long, and deciduous; the leaflets opposite or nearly so, from 4 to 8 pairs, the lower ones broad-ovate, smooth, obtuse, or emarginate, polished on both sides, on short, round petioles, from 2 to 6 inches long, and from 1 ½ to 3 broad. The flowers are large, fragrant, bright-yellow, and borne on long, slender, smooth pedicels. The racemes are axillary, pendulous, simple, and 1 or 2 feet long. The calyx is composed of 5 nearly equal, oblong, obtuse, smooth sepals. The corolla consists of 5 petals, which are oval, unequal, concave, spreading, and waved. The 3 lower filaments, much longer than the others, have a double curve, but no swelling. The anthers on the 3 long filaments are oblong, opening by 2 lines on the face, while the other 7 are clavate, with pores at the small end. The ovary is filiform, smooth, cylindrical, curved, and 1-celled, containing numerous seeds, The fruit is a woody, dark, blackish-brown, cylindrical pod or legume, a foot or more in length, about an inch in diameter, terete, smooth, blunt, indehiscent, filled with a viscid, reddish-black, sweetish pulp, divided into many cells by hard, transverse phragmata; the cells 1-seeded; and the seed oval, glossy, and somewhat flattened (L.).
History.—Purging cassia inhabits Egypt and the Indies, and has become extensively diffused in various tropical countries, as China, Hindustan, West Indies, Brazil, etc. The part used in medicine is the fruit or pods, and those are to be preferred which are heavy and new, and do not, when shaken, make a rattling noise from the seeds being loose within them. The pulp should be of a bright, shining, black color, and have a sweet taste, neither harsh, from the fruit being collected before it is fully ripe, nor at all sourish, which it is apt to become on keeping, nor at all moldy, which is frequently the case when kept in damp cellars, or moistened to increase its weight (Ed.) To obtain the pulp, the pods are pounded, so as to break their outer coat, and then they are infused in boiling water, which dissolves the pulp; the infusion is then strained, and evaporated to the proper consistence.
Description.—"Cylindrical, 40 to 60 Cm. (16 to 24 inches) long, nearly 25 Mm. (1 inch) in diameter, blackish-brown, somewhat veined, the sutures smooth, forming two longitudinal bands; indehiscent, internally divided transversely into numerous cells, each containing a reddish-brown, glossy, flattish-ovate seed imbedded in a blackish-brown sweet pulp; odor resembling that of prunes"—(U.S. P.).
Chemical Composition.—-The pulp has a feeble, nauseous odor, a mucilagino-saccharine taste, and contains, according to Henry, sugar, gum, impure tannic acid, coloring matter, a gluten-like matter, and moisture. It keeps longest when preserved in the pod. It is largely soluble in water, and its active parts are taken up by alcohol.
Action, Medical Uses, and Dosage.—-One or two drachms act as a mild and effectual laxative; 1 or 2 ounces are cathartic, but excites nausea, flatulence, gripings, etc. (Ed.). It tints the urine brown or green. It is generally employed only in the electuary of senna.
Related Species.—Cassia moschata, Kunth (Cathartocarpus moschatus, Don). Central and northern South America. Yields a purging cassia, resembling the official, though not quite so uniformly straight, and is from a foot to nearly 20 inches long, and of a light color. Its pulp is sweet, subastringent, and of a reddish-brown color. A sandal-wood fragrance is emitted when the crushed legumes are heated in a water-bath (Pharmacographia).
Cassia bacillaris, Linné filius (Cathartocarpus bacillus, Persoon).—Yields a drug essentially corresponding with the preceding.
Cassia brasiliana, Lamarck (Cassia grandis, Linné filius; Cathartocarpus brasiliana, Persoon; Cassia mollis, Vahl), Horse cassia. Brazil and Central America. Larger than purging cassia legumes; sutures prominent, and pulp astringent, bitter, and purgative. They are compressed, may be curved, and have dividing veins running transversely.
Ceratonia siliqua, Linné.—Mediterranean countries. An evergreen tree bearing purple, apetalous flowers, and producing a fruit known as St. John's bread, somewhat resembling purging cassia. Employed in Europe in connection with demulcents and pulmonary mixtures. Besides sugar and glucose, mucilage, tannic acid, and proteids, the fruit contains free isobutyric acid ([CH3]2CH.COOH). A more recent analysis of Ceratonia siliqua is recorded in the Amer. Jour. Pharm., 1893, p. 131.