Cusso (U. S. P.)—Kousso.
The female inflorescence of Hagenia abyssinica (Bruce), Gmelin"—(U. S. P).(Brayera anthelmintica, Kunth; Banksia abyssinica, Bruce).
COMMON NAMES: Kooso, Cusso, Kousso, Kusso, Kosso, Cossoo.
ILLUSTRATION: Bentley and Trimen, Med. Plants, 102.
Botanical Source.—This is a tree growing about 20 feet high, with round, rusty, tomentose-villose branches, marked by the annular cicatrices of the fallen leaves. The leaves are crowded, alternate, interruptedly imparipinnate, and sheathing at the base. The leaflets are oblong, or elliptical-lanceolate, acute, serrate, villose at the margin and on the nerves of the under surface. The stipules are adnate to the petiole, which is dilated at the base, and amplexicaul. The flowers are dioecious, small, greenish, becoming purple; repeatedly dichotomous; and with pedicels with an ovate bract at the base. The so-called male flowers may be regarded as hermaphrodite flowers, inasmuch as the carpels are well developed. Female flowers somewhat different in their structure. The outer segments of the calyx are much more developed than in the female flowers, are 4 or 5 times larger than those of the inner row, and placed somewhat below them; the petals are entirely wanting; the stamina are rudimentary and sterile. The ripe fruits are unknown (Kunth).
History.—This plant was introduced into notice by a pharmacist of Paris, and its properties as an anthelmintic were investigated by the Academy of Medicine and the Academy of Sciences as early as 1847. It grows in Abyssinia, the flowers being the parts of the plant used. They are reduced to a fine powder, which is brownish, like jalap, bitter, somewhat nauseous, and possessed of an odor similar to scammony. The flowers, not powdered, have a somewhat fragrant odor, and a slight taste, which soon becomes nauseous and acrid. The plant was named in honor of Dr. Brayer, who first made its virtues known in Europe. Bruce, in his Travels, Vol. VII, appendix, gives a minute description of the plant, and calls it, in testimony of esteem for a friend, "Banksia abyssinica." Dr. Kirk, in the appendix to the second volume of the "Highlands of Ethiopia," by Sir W. C. Harris, calls it "Hagenia abyssinica," and states "that a cold infusion of the dried flowers and capsules, constitutes the famous drasticum purgans and anthelminticum of the Abyssinians." Both the male and female inflorescence are collected, though the latter only are official in the U. S. P. The dried male flowers are of a pale, greenish-brown hue, and are frequently termed kooso-esels. The commercial female flowers are of a light, brown-red color, and are known as red kooso. The inflorescence is collected before the ripening of the fruit, forming loose, dried panicles, which, as found in commerce, are often considerably broken.
Description.—The U. S. P. thus describes the official cusso: "In bundles, rolls, or compressed clusters, consisting of panicles about 25 Cm. (10 inches) long, with a sheathing bract at the base of each branch; the two roundish bracts at the base of each flower, and the 4 or 5 obovate, outer sepals are of a reddish color, membranous and veiny; calyx top-shaped, hairy, enclosing 2 carpels or nutlets; odor slight, fragrant and tea-like; taste bitter, acrid, and nauseous"—(U. S. P.)
Chemical Composition.—Wittstein found the flowers to contain gum, wax, bitter acrid resin, sugar, tasteless resin, fatty matter, chlorophyll, tannin, and lignin. The first-named resin is identical with koussin.
A preparation named koussin was made by M. Pavesi and M. Vée, according to the following process: Treat kousso (300 parts) with alcohol (100 parts), and calcium hydrate (25 parts), at a temperature of 60° to 65.5° C. (140° to 150° F.). Also digest the residue with barley water (600 parts). Mix the solutions thus obtained, filter, and precipitate by means of acetic acid. The koussin thus obtained is yellow, bitter, resinous, non-crystallizable, and insoluble in cold alcohol. Merck obtained it in well-defined rhombic crystals of sulphur-yellow color, readily dissolving in chloroform, ether, carbon disulphide, and benzol; less soluble in glacial acetic acid, and alcohol of specific gravity 0.818, and not at all soluble in water. Flückiger (Pharmacognosie, 1891) states that koussin crystallizes best on cooling its solution in concentrated sulphuric acid, saturated at 15° C. (59° F.). It is dissolved by alkalies, while acids reprecipitate it, unaltered, as an amorphous, white mass, which may be again obtained in crystals from solution in hot alcohol. Koussin is not chemically altered by cautiously melting it; in this condition it remains as a yellow, amorphous, transparent mass, which, if simply touched with a minute portion of alcohol, instantly assumes the form of stellate, crystalline tufts. When treated with concentrated sulphuric acid, if water is added to the solution, amorphous white koussin is precipitated. If the (yellowish) solution of koussin in concentrated sulphuric acid is allowed to stand for a few days, or if it be carefully warmed, a scarlet-red coloration makes its appearance, isobutyric acid, but not sulphurous acid, being formed as a by-product. On diluting the red solution with water, purple-red amorphous flakes are precipitated. These vary in composition from C22H21O10 to C23H22O10. Flückiger and Buri assign to Merck's koussin the composition C31H38O10 (Pharmacognosie, 1891). This principle has been variously termed kousin, kosin, koosein, brayerin, and taeniin. It is notable that the pure kousin is not so active an anthelmintic as the amorphous product obtained by Pavesi's method.
Action, Medical Uses, and Dosage.—Purgative and anthelmintic. Used by the Abyssinians for tapeworm, to which they are very subject, and it is said they will not travel without having some of the kousso with them. The dose of the flowers in powder is a small handful, or about 4 1/2 drachms, which is to be macerated in about 3 gills of lukewarm water for 15 minutes. The infusion, with the powder suspended in it, is taken either in 1, 2, or 3 doses, quickly following each other. It is recommended that lemon-juice, or tamarind water, should be taken freely before and after the kousso. The patient must be prepared by a low diet for 1 or 2 days previously, and by a dose of castor oil, or other purgative, and the kousso is to be taken on an empty stomach early in the day. The clear infusion has the color, and a somewhat similar taste, of very weak senna tea. Its operation is safe, speedy and most effectual, rarely causing any annoyance or uneasiness, except a slight nausea, and this but seldom; occasionally emesis takes place, or diuresis. A gentle cathartic after its operation is also advisable. As far as it has been used, when fresh, it has not failed to kill and expel the worm.