This section is from the book "Materia Medica And Therapeutics: An Introduction to the National Treatment of Disease", by John Mitchell Bruce. Also available from Amazon: The pharmacology and therapeutics of the materia medica.
The leaflets of Cassia elongata. From plants cultivated in Southern India.
Characters. - About two inches long, lanceolate, acute, unequally oblique at the base, flexible, entire, green, without any admixture; odour and taste those of Alexandrian Senna.
Composition. - Senna contains an active principle, cathartic acid; a colouring matter closely allied to chrysophanic acid; peculiar unfermentable sugar, catharto mannite; other obscure glucosides, sennapicrin and sennacrol; and various vegetable salts. Cathartic acid, a highly important body, is an amorphous glucoside, C180H192N2SO82, which forms salts with bases, and can be broken up in into glucose and cathartogenic acid.
Dose. - 10 to 30 gr. in powder.
Preparations of either kind of Senna:
Confectio Sennae. 1 in 11 with Coriander, Figs, Tamarinds,
Infusum Sennae. 1 in 10. Dose, 1 to 2 fl.oz.
From Infusum Senna is prepared: a. Mistura Sennae Composita, - Infusion of Senna, 14; Tincture of Senna, 2 1/2; Sulphate of Magnesia, 4; Extract of Liquorice, 1/2; Compound Tincture of Cardamoms, 1 1/4. Dose, 1 to 1 1/2 fl.oz.
Svrupus Sennae. 1 in 2. Dose, 1 to 4 fl.dr.
Tinctura Sennae. 1 in 8. Dose, 1 to 4 fl.dr.
Senna is also the most important ingredient in Pulvis Glycyr-rhizie Compositum. 2 in 10. See Glycyrrhizae Radix, page 224.
Given internally, senna stimulates the muscular coat of the intestine, apparently by local reflex action, originating in the mucous surface of the bowel itself; and produces brisk peristaltic movements and purgation within four or five hours. The colon is chiefly stimulated, hurrying downwards the fluid contents received from the ileum, which appear as very thin copious yellow stools, with excess of soda salts and digestive products, but no special increase of bile. Full doses cause repeated evacuation and griping, but no inflammation of the mucous surface. The pelvic structures may, however, become hypersemic, leading to haemorrhoids and the appearance of the menses. Constipation does not follow the use of senna.
Senna is never given alone, but always with a carminative to prevent griping, and frequently with other purgatives, as in the compound mixture. It is one of the most useful of purgatives. It is very extensively prescribed to complete the effect of mercurial and other duodenal purgatives, given several hours before. It affords at once a rapid and a safe purge at the commencement of febrile attacks in children, in local inflammations, and in cerebral congestion. As an habitual laxative in the form of Pulvis Glycyrrhizae Compositus, senna is most valuable as a simple stimulant of the muscular coat, which neither loses its effect by use, nor produces subsequent constipation. Combined with bitter and other stomachics, it is useful in atonic dyspepsia, its laxative effect being increased by acids but diminished by alkalies.