This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
Senna. - The leaflets of Cassia acutifolia Delile (Alexandria Senna), and of Cassia angustifolia Vahn (India Senna); (nat. ord. Leguminosae).
Alexandria Senna consists of leaflets about 25 mm. long and 10 mm. broad, lanceolate, or lance-oval, subcoriaceous, brittle, rather pointed, equally oblique at the base, entire, grayish-green, somewhat pubescent, of a peculiar odor, and a nauseous, bitter taste.
Eastern and Central Africa.
Resembling Senna. - Argel leaves (the leaves of Solenostemma Argel Hayne, (nat. ord. Asclepiadeae), which are frequently present; these leaves are thicker, one-veined, wrinkled, glaucous and are equal at the base, as also are the leaves of Uva Ursi and Buchu.
India Senna. - Synonym. - Tinnivelly Senna. Consists of leaflets from 3 to 5 cm. long and 10 to 15 mm. broad; lanceolate, acute, unequally oblique at the base, entire, thin, yellowish green or dull green, nearly smooth; odor peculiar, somewhat tea-like; taste mucilaginous, bitter and nauseous.
Eastern Africa to India; cultivated.
Stalks, discolored leaves, and other admixtures. Composition of Both Kinds. - The chief constituents are - (1) Cathartic Acid, C180H192N82So2, an amorphous sulphurated Glucoside. It exists as salts of earthy bases, such as Calcium and Magnesium, which are soluble in water. Cathartic Acid is capable of decomposition into Glucose and Cathar-togenic Acid. It is the chief purgative principle in Senna and other purgatives.
(2) Sennacrol and Sennapicrin, C34H58O17, glucosides, which do not, in most preparations, contribute to their action, as they are insoluble in water.
Dose, 1 to 3 dr.; 4. to 12. gm.
1. Confectio Sennae. - Confection of Senna. Senna, 100; Oil of Coriander, 5; Fig, 120; Tamarind, 100; Cassia Fistula, 160; Prune, 70; Sugar, 555; Water to make 1000. By sifting, digestion and evaporation.
Dose, 1 to 2 dr.; 4. to 8. gm.
Fluid Extract of Senna is used to prepare Syrupus Sarsaparillae Compositus.
Dose, 1 to 3 fl. dr.; 4. to 12. c.c.
Dose, 1 to 2 fl. oz.; 30. to 60. c.c.
Dose, 1/2 to 2 dr.; 2. to 8. gm.
5. Syrupus Sennae. - Syrup of Senna. Alexandria Senna, 25; Oil of Coriander, 5; Sugar, 700; Alcohol, 150; Water to 1000. By digestion, straining, evaporation and filtration.
Dose, 1/4 to 1 fl. oz.; 8. to 30. c.c.
Senna, because of the cathartic acid in it, stimulates the muscular coat of the intestine, especially the colon, and produces some hyperaemia. Consequently the fluid contents of the small intestine are hurried through the colon, and pale yellow watery stools, containing some undigested food, are the result. Senna acts very feebly or not at all on the biliary secretion. Large doses open the bowels several times and produce griping, but not much hyperaemia. Probably there are other substances in senna, besides cathartic acid, having a purgative property, but it is by far the most important. Purgation by senna does not subsequently cause constipation. Some constituents of it are absorbed, and may cause the urine to be red. It will purge, if injected into the veins, and will impart its purgative properties to the milk of nursing women.
Senna is a safe, useful purgative for cases of simple constipation. It is, because of its tendency to gripe and its nauseous taste, rarely given alone. The compound liquorice powder is to be preferred to the compound infusion of senna ("black draught "), as this is a disagreeable mixture. Senna is largely used to complete the effect of duodenal purgatives, as we see in the old prescription of a blue pill at night and a black draught in the morning. Acting on the colon, it is valuable in slight cases of faecal collection. Compound liquorice powder is much used in habitual constipation and the constipation of pregnancy. Confection of senna, coated with chocolate, forms the well-known purgative, Tamar Indien, and in this form can be taken by children. It is said that an infusion contains more of the active principles than the other preparations; it soon decomposes, but nitre 1 to 480 will prevent this.